Extinction is forever!

Kristen Strimel

kstrimel@lhup.edu

November 6, 2003

Psychology Major

Extinction

"Extinction is known as the process in which groups of organisms die out" (enchanted learning software, p. 1). Practically all of the species that have ever lived on earth have gone extinct at some point in time. One example of extinction is seen with the dinosaurs who disappeared from the earth approximately sixty-five million years ago. Although much of life as we knew it then had been wiped off the face of the earth at this time, many species had died due to a series of background extinctions that had occurred. These background extinctions were the result of several factors some of which include the gradual changes in the environment, the decrease of resources, competition with other animals, as well as other factors in which adaptation would be needed. Although many species inhabiting the earth died due to these background extinctions, the dinosaurs were part of a mass extinction. "A mass extinction is a relatively sudden, global decrease in the diversity of life forms. For a situation to be considered a mass extinction, extinctions must occur all over the world, a large number of species must go extinct, many types of species must go extinct, and the extinctions must be within a short amount of geological time" (Enchanted Learning Software, p. 2).

This graph depicts the periods in which the five largest mass extinctions in Earth's history have occurred. The first mass extinction occurred in the late Ordovician period which occurred around 438 million years ago. It constituted the extinction of one-hundred families including more than half of the Brachiopods and Bryozoan species. The second extinction occurred in the late Devonian period. This period occurred 360 million years ago and approximately thirty percent of animal species became extinct. The third mass extinction to occur was in the Permian period which occurred 245 million years ago. This period consisted of the extinction of fifty percent of all animal families, ninety-five percent of all marine species, and the dieing out of many trees. The fourth mass extinction occurred in the late Triassic period around 208 million years ago. Thirty-five percent of all animal families died out along with most of the early dinosaurs. Many of the synapsids died out except for the mammals. The last mass extinction occurred at the Cretaceaous-Tertiary boundary about 65 million years ago. This extinction is where half of all life forms on Earth died out including the dinosaurs.

Ordovician Period

The Ordovician period was known as the first mass extinction and occurred 438 million years ago. This period in time is best known for its diverse marine life. During this period, large glaciers began forming which caused shallow seas to drain, which in turn, caused sea levels to drop. These glaciers are thought to be the cause of the mass extinction that had occurred. Brachiopods are one of the marine animals that had suffered in this period. Brachiopods are marine animals that look similar to clams but are different in their anatomy. They belong to a group called Bilateria because they are bilaterally symmetrical. There are approximately 300 living species of Brachipods today and they are thought to be fairly common. Although this species is common, they live in cold water in the depths of the ocean making them hard to come in contact with.

Bryozoan were another species that was greatly affected in this time period. Bryozoan are also known as moss animals and are aquatic species living in colonies of interconnected individuals. These colonies can be made up of  millions of Bryozoan or only a few. These colonies can range from millimeters in size to meters, however these Bryozoan are usually no bigger than a millimeter themselves. There are currently 125 species of Bryozoan which can usually be found on the bottom of ships. Although these species play a role in reducing the efficiency of ships and clogging public and industrial water tanks, they are being put to good use. Because Bryozoans produce a variety of chemical compounds, a compound called bryostatin 1 has been produced because of the possible effects it may have on being used as an anti-cancer drug. A compound from Bugula Neritina, which is a form of Byrozoan, is being used to develop new cancer treatments to help treat leukemia as well as certain melanomas. When this drug is combined with chemotherapy, they block signaling pathways that are essential to cells survival, and enhance the ability of chemotherapy to fight off the cancer cells. Because scientists are still researching how effective this bryostatin 1 is, they need many of these organisms to experiment with, which is causing a problem because they are depleting the population of these organisms. To solve this problem, some researchers have turned to harvesting these organisms in aquaculture tanks so that they can investigate their use while maintaining this particular ecosystem.

Devonian Period

The Devonian period was known as the second greatest mass extinction and occurred 360 million years ago. This period was nicknamed the Age of Fishes because all of the major fish groups were present at this time. This era consisted of high sea levels and warm climate. One example of a species of fish that was present at this time was the Ostracoderms. These fish have bony skin and have no jaws. One many think that this type of fish lacks protection but this fish had a head shield used for defense.

Another species of fish that existed during this time was Placoderms. Placoderm literally means plate skin. This skin covers the entire skeleton and serves as an armor. Placoderms are thought to be the most diverse group of early jawed fish. Although these fish have no teeth, the crushing structures on their jaw serve as a substitute for teeth. A more specific example of a Placoderm was Dunkleosteus. This species was a spiny shark thought to be thirty feet long. This particular picture illustrates the crushing structures used as teeth.

Another species of fish found in this era was Acanthodians. These fish were known for their bony spines and diamond shaped scales. They typically have large set eyes near the front of their heads. They were the first to have vertebrate and a jaw. Although they were mainly found in salt water, freshwater forms began to dominate in this era. These fish were thought to be small but some of them could grow up to a meter long. The preyed on small vertebrate and jawless fish. This group of fish showed little diversity, most coming from four to nine families belonging to three main groups. The first group was the Climatius which had a short, deep body and had five pairs of fins below its stomach. The next group was the Ischnacanthus. This fish was thought to be more advanced with fewer but larger spines. These spines were longer and thinner. The last group were known as acanthodes and was scale-less in some places. This fish had fewer fins and spines and had no teeth. It averaged one foot long.

Cartilaginous fish also existed in this particular time period. The skeleton of these fish are made up of cartilage. Only their teeth and some vertebrate are calcified. Some of this species feed on plankton while others feed on meat. There are five types of feeding methods which include "specialized teeth for grasping and chewing for predators, small bites for nibblers, use of gill rakers to strain the food floating in the currents for the food strainers, bottom feeders who draw food through the mouth like a vacuum cleaner who are known as food suckers, and parasites who attach themselves to other fish and live off its juices" (fish, p. 2).This particular species is very diverse, consisting of sharks and  manta rays to mollusks. There are approximately 800 species which are typically found in saltwater although some can be found in freshwater. Although many of these species seem dangerous, only a few truly are. Those species who are dangerous, play a very important role in that they keep the food chain balanced and keep the ecosystem in check. Their fins play a major role because it keeps them from sinking due to the fact that they do not possess an air bladder.

              

Another species that existed during the Devonian period were the bony fish which were made up of two groups. One group was ray-finned fish and the other group was lobe-finned fish. Ray-finned fish started in the lakes and streams and then eventually migrated to the ocean. These fish have webs of skin supported by bony spines. This species is the most dominant today and can be found in every aquatic environment. Some of these fish can even crawl on land for a short time but must then return to the water. These types of fish serve as a very abundant food source. The lobe-finned fish have muscular fines with articulating bones. 360 million years ago, the young fish of the species spent most of its time in the deeper waters while the adult fish tended to swim in the shallows. These fish were related to the ancestors of amphibians and possessed both lungs and gills. When these fish experienced overcrowding in the lakes they used their fins to move onto dry land. As a result, their fins had turned into feet. Lungfish and crossopterygians are the two groups in which the lobe-finned fish are divided into. Lungfish can be found living in our freshwater today. Their lungs are not well developed so most of the time they breath through their gills. Lungfish have only one lung and although capable of surviving on land for a few days it must return to the water. The crossopterygians are important because they gave rise to amphibians. The crossopterygians are know as Rhipidistians which are a freshwater family. A group of these fish became deep sea dwellers and because of this there is no fossil record of them after 65 million years ago. Although their is no fossil record of them, a living specimen was caught in 1939 from a deep sea trench off the coast of Africa. One of the most unique characteristics that these animals are said to possess is a skull bone pattern that is similar to amphibians. "There are two bones at the roof of the skull which correspond to the parietal bones in terrestrial vertebrates, and between them is an opening for the pineal gland or "third eye", which in terrestrial animals serves as a light indicator to calibrate the internal clock" (ichtyostega, p. 1).

                       

Permian Period

The Permian period occurred around 245 million years ago and was known as the third mass extinction. This period in time not only affected animals and many trees but it devastated the marine population killing ninety-five percent of all marine species. Although some groups had survived the devastation, they never again were as dominant as they had been. Because most of the forests back in this time period were composed of fern-like plants, this devastation caused many trees to shift to gymnosperms. These gymnosperms produced offspring that were enclosed within a seed for protection. The modern conifers that we have today, first appeared here in the Permian period. During this time the earth consisted of massive portions of both land and water and because the formation of the glaciers seemed to be decreasing, the interior of the land became drier. The climate at this time was said to fluctuate greatly. No one knows for sure what caused this massive extinction but many theories are being proposed to explain this phenomena. One theory is that the increase in glaciers caused the environment to cool and caused sea levels to drop. Another theory is the reduction of shallow continental shelves. This reduction in shelves would cause organisms to have to compete with one another. Another theory for this extinction is the rapid warming and severe climatic fluctuations. The last theory proposed has to due with volcanic eruptions. Some paleontologists believe that lava eruptions in Siberia sent sulphates into the air and may have been explosive. This could have sent large ash clouds around the world lowering climate conditions. Although this period brought devastation to many species of living things, this period also brought extinction to one species known as the Trilobites.

Trilobites

Trilobites are hard shelled, segmented animals and are said to be the single most diverse group of extinct organisms. This species was found world wide in a variety of aquatic environments including  tropical shallows and reefs to polar depths but never freshwater.  These organisms range in size from one millimeter all the way up to two feet. Growth for these organisms involved a process of molting. This process is where the body within becomes to big for the exoskeleton and therefore must be shed. After this molting takes place, this organism is covered only by a flexible shell which will eventually harden. There are three major periods of growth recognized with this species. The first period of growth is known as the protaspid period. The period is from the time of hatching to the definition of the cephalon. The next growth period is known as the meraspid period. The overall size of the trilobite increases up to ten times the size of when it was in the previous period. This period comes to an end when the trilobite develops the number of thoracic segments needed to be an adult. The last period is known as the holaspid period. This period is characterized by the moltings that the trilobite goes through. The body of this organism also contains segmented appendages some of which were used as claws. To help these organisms navigate their environment, they had antennulae and single or compound eyes used a sensory organs. They were thought of as predators-scavengers and most tended to stay on the bottom of the ocean in search of food. They also used the bottom of the ocean as a source of protection because they were able to dig into the sediment and hide from animals that were searching for them. Another source of protection that these organisms possessed was the ability to enroll themselves so that their hard exoskeleton was exposed.

                                           

Triassic Period

The Triassic period was the fourth mass extinction which occurred 208 million years ago. The organisms of this period can be broken down into three groups. Holdovers from the Permo-Triassic extinction, new groups which flourished briefly, and new groups who dominated. The holdovers from the other era consisted of lycophytes, glossopterids, and dicynodonts. The lycophytes are a small group of plants found today, but back in this era, they could grow more than thirty-five meters tall. The mosses are usually evergreen and can form on the ground of wet tropical forests. The most significant feature of this plant is the microphyll. This is a leaf with a single un-branched strand of vein. The glossopterids are an extinct group of seed plants. Because this group of seed plants appeared and then became extinct so rapidly they have become very important to try to understand. This group was thought to be deciduous meaning they lost their leaves in the autumn and growing new leaves in the spring. Mature leaves were ten centimeters long and could be found in size over a meter in length. The dicynodonts were a family of mammal-like reptiles from which true mammals descended. These animals were all sizes ranging from the size of a rat to the size of a cow. Although most of these animals were herbivores some of these animals were burrowers. This first true mammal was known as an Eozostrodon. This was a small, egg-laying animal who fed her young with milk. This animal had four legs, a pointed nose, a long hairy tail, and five toes with sharp claws. This animal was only 42 inches long and had teeth that were only replaced once. The earliest known turtle also appeared during this era. Frogs, salamanders, and lizards appeared as well. Peterosaurs first appeared in this period and they were characterized as winged lizards. They were as small as a few inches or as big as forty feet long. They had bony crests on the top of their head that were thought to act as a ruder or could have been a sexual characteristic. These reptiles were carnivores and flew very long distances in search of fish.

                       

        

Cretaceous-Tertiary Period

The Cretaceous-Tertiary period occurred around 65 million years ago and this is when half of all life forms on earth died out including the dinosaurs. This boundary separated the age of reptiles with the age of mammals. The Cretaceous period lasted from 135 to 65 million years ago while the Tertiary period occurred from 65 million years ago until the present. Because some many of our species on the planet became extinct and not just the dinosaurs many people wanted to know the cause of such an extinction.

 

                               

The Asteroid Theory

This theory was proposed by Luis and Walter Alvarez in the late 1970's and seem to be the most supported today. They discovered that the thin layer of clay they were examining around the K-T boundary in Italy contained large amounts of iridium which is an element common in meteorites. Because of the high concentrations of iridium, they proposed that the earth was struck by a large asteroid. It was calculated that an asteroid approximately ten kilometers in diameter would contain enough iridium to account for the element found in the clay. Analysis of this clay layer has revealed the presence of soot which comes from very large global fires that would have been the result of temperatures caused by an impact (Dinosaur Extinction, p. 3). Another element that was found in the clay was quartz crystals which had been altered. This alteration only occurs in extreme temperatures and pressure.

                                   

In 1990, a scientist named Alan Hildebrand found evidence of what could have been an impact site located in the Yucatan region of Mexico. He located a ring structure 180 kilometers in diameter which was called Chicxulub. This crater has been dated as being 65 million years old.

 

"At the velocity in which this crater impacted, there would have been an initial blast which would have destroyed everything within a radius of 400 to 500 kilometers. At the same time large fires would have been started by the intense shock wave. Trillions of tons of debris would have been thrown into the atmosphere. Tidal waves would occur causing even more damage. The blast would also have started a chain reaction of earthquakes and volcanic activity along with high winds. Because of these winds, this debris would have been carried for long distances. This debris would cause months of darkness and a decrease in temperature. After this there would be an increase in temperature caused by large amounts of CO₂ which was caused by the global fires. This would cause chemical reactions which would result in acid rain" (Dinosaur Extinction, p. 6). These global fires destroyed large amounts of vegetation needed for the larger animals to survive. Because these herbivores were dying because of lack of food, this would effect the food chain and the carnivores would have died off. Only active scavengers and birds would have been able to survive this because of their ability to go long distances for food. The sea would have been affected just as dramatically because of the decrease of oxygen in the water. There also could have been an increase in the acidity of the water due to the amounts of acid rain.

What is a Threatened Species?	"According to the U.S. Fish and Wildlife Service, a threatened species is a plant or animal in danger of extinction in the foreseeable future" (Paragraph 1).
"According to the U.S. Fish and Wildlife Service, an endangered species is any plant or animal in danger of extinction throughout all or a significant portion of their range" (Paragraph1).	What is an Endangered Species?

How to Get a Species Listed As Threatened or Endangered

The U.S. Fish and Wildlife Service recognize three major steps in getting a species listed as threatened or endangered. These three steps include listing, consultation, and recovery. The first major step, listing, can be broken down further into five sub-steps. The first sub-step of the listing process is candidate lists. These candidate lists include any species "that are , or have been, under consideration for listings, which are referred to as candidate species" (Brenner, Majumdar, and Rhoads, p. 77). Candidate species listed in the notice can also be divided into three groups. "Category 1 species are those for which there is enough information to warrant listing and anticipates the publication of a rule proposing to list them as threatened or endangered. Category 2 species are those for which listing may be appropriate but existing status information is not sufficient enough to support listing. Category 3 is reserved for those species that are no longer under consideration for listing" (Brenner, Majumdar, and Rhoads, p.77). This picture of a sheath-tailed bat is an example of a candidate species.

The second sub-step in the listing process is status surveys. These status surveys are given to biologists or other organizations who have extensive knowledge of a particular group. "These surveys will assess the group's presence, viability and threats it faces at historical sites and other suitable habitat throughout its range" (Brenner, Mujumdar, and Rhoads, p.78). These reports should provide enough information so that the US Fish and Wildlife Service can decide whether the species should be listed as threatened or endangered. This determination of whether an animal or plant should be listed as threatened or endangered is based only on scientific and commercial data.

The third sub-step of the listing process is obtaining listed status. One the service has determined that a plant or animal should be listed as threatened or endangered, the next step is to prepare a proposal for publication in the Federal Register. "The listing proposal summarizes the threats facing the species under the following categories:

• the present or threatened destruction or modification or curtailment of its habitat or range

• over utilization for commercial, recreational, scientific, or educational purposed

• disease or predation

• the inadequacy of existing regulatory mechanisms

• other natural or manmade factors affecting its continued existence

If critical habitat is proposed then all of the documents must be sent to the central Office of Endangered Species in Arlington, Virginia, for review and clearance" (Brenner, Mujumdar, and Rhoads, p. 78). If the document is approved, then it will be published in the Federal Register. At the time of publication, everyone that could be affected by this publication is notified. Not only is everyone that will be affected notified but this announcement must be published in newspapers in the affected area. After it is published in the newspaper, "there follows a sixty day period in which written comments on the proposal are accepted. Also from the date of publication there is a forty-five day period during which any interested party may request a public hearing concerning the listing" (Brenner, Mujumdar, and Rhoades, p. 78). Within one year of the original publication the proposal can be withdrawn or a final rule implementing the proposal must be published. These final rules must include any comments made during the sixty day period and summarize the content of any hearings that had occurred. Final rules are also subjected to comments within the service prior to publication. Final rules typically become effective thirty days after the date of publication.

The fourth sub-step of the listing process is the petitioning process. This petitioning process is where any person interested in having a species listed must petition the service to do so. Although anyone can petition the service for a particular species, there must be biological data to support the need of the species to be listed. After the service receives this petition, they have ninety days to publish whether they have received sufficient evidence as to whether that species will be listed. If the service finds sufficient information, the listing proposal must be published as soon as possible.

The last sub-step of the listing process is emergency listing. The emergency listing is "for the extreme case in which a previously unprotected species is suddenly faced with imminent danger, posing significant risk to its well-being" (Brenner, Mujumdar, and Rhoads, p. 79). When this emergency listing is needed, the service is able to publish an emergency regulation which becomes effective immediately providing listed status for that particular species. This listing is effective for 240 days, and during this time a regulation must be published through the proper way of getting a species listed permanently.

The second major step is consultation. The consultation step "requires all Federal agencies to ensure that any action they authorize, fund or carry out is not likely to jeopardize the continued existence of any endangered or threatened species" (Brenner, Mujumdar, and Rhoades, p. 80). Consulting with the Federal agencies is very important because these agencies play a major role in destroying the habitat of so many important species. Usually this whole process begins with an informal consultation in which an employee from the Federal agency reviews a list of endangered and threatened species that occur in a project area. If any species is known or found to be in this particular area, the service works with the agency so that no harm is done to that particular species. For very important Federal projects, a biological assessment must be done which reviews any impact from the project that listed and proposed species may endure. Usually this assessment will be completed within 180 days and will determine whether or not there will be any affect on a specific species. There are also instances in which a certain project may affect a certain species and when this occurs, the Federal agency must submit to have a formal consultation. During this formal consultation, a biologist from the service works with the agency to find other alternatives so that species are not harmed in the process. This process is usually completed within ninety days and a document is developed as to whether or not the project will affect the continued existence of a species. If an affect is determined, then the service must list any alternatives that they find applicable. Although this formal consultation is very well outlined, the use of it is decreasing because conflicts are being resolved through careful project planning.

 

The third step is the recovery process and the aim of this step is to "restore listed species to the point where they no longer need the protection of the Act" (Brenner, Mujumdar, and Rhoades, p. 81). To execute this goal, the service develops recovery plans for each species. "The recovery plan outlines the tasks necessary for recovery and describes these tasks, including the responsible agency or agencies and the estimated costs" (Brenner, Mujumdar, and Rhoades, p. 81). The recovery plans may be developed by several different people including the service biologist, a private individual or institution, or a recovery team appointed by the service. These recovery plans are subjected to review just like everything else before they can be signed by the director. All of the plans are approved and reviewed every year and may be updated if needed. "Recovery plans specify such techniques as periodic monitoring, studies of ecological requirements and aspects of life history, habitat acquisition, and habitat manipulation" (Brenner, Mujumdar, and Rhoades, p. 81). This process also assures that the most critical of species receives recovery plans first.

One example of trying to reintroduce a species back into its environment so that it no longer needs the protection of the Endangered Species Act is seen with the California Condor. Historically these birds have ranged throughout the southern United States, but by the 1940's they were only found on the West Coast and by 1967 they were listed as endangered under the Endangered Species Act. As of January 2000, the total population of these birds was 158 and of those only fifty-three were in the wild. California Condors are the largest North American land birds and among the largest flying birds in the world. These birds usually weigh around twenty-two pounds with a wing span of up to nine and a half feet. "Condors will breed once every other year, with an elaborate courtship flight and dance leading up to mating" (Ventana Wilderness Society, paragraph 5). This could possibly be one of the reasons why it is so hard to increase the number of these creatures. Raising a chick of this species is a lot of work so a pair will only lay one egg per season. Parents will look after their young for up to two years after hatching. These birds feed on the carcasses of other animals and will go as far as 150 miles a day in search of food. Because of the ever changing availability of food, condors have been documented not feeding for up to fourteen days at a time. There is evidence to suggest that the condors mortality is due to two factors. These factors are lead poisoning and shooting. These two factors have contributed to the decline of the species in recent years. The lead poisoning is due to the ingestion of fragments of lead bullets in mammal carcasses. And regardless of whether this species is endangered, there are still instances where these animals are being shot. In July of 1992 a person was arrested for shooting at a condor that was part of a reintroduction program.

Although the United States has developed a clear system in getting species listed as threatened and endangered, there are ways to do this on an international scale as well. "The World Conservation Union, through its Species Survival Commission has for four decades been assessing the conservation status of species, subspecies, varieties and even selected subpopulations on a global scale in order to highlight taxa threatened with extinction, and therefore promote their conservation" (The IUCN Red List of Threatened Species, paragraph 1). This Red List includes information on groups of animals that are thought to be extinct or extinct in the wild, animals that cannot be evaluated because of insufficient information, and animals that would be threatened were it not for the conservation programs. The groups that have been fully assessed against the new criteria are the mammals and birds. The plants species have not yet been assessed against the revised criteria so this group will not be included in the international information listed here. All of the information gathered for this Red List was compiled by members of the Species Survival Commission and the birds were assessed by Birdlife International. "In order to produce Red Lists of all threatened species worldwide, the Species Survival Commission has to draw on and mobilize a network of scientists and partner organizations working in almost every country in the world, who collectively hold what is likely the most complete scientific knowledge base on the biology and conservation status of species" (The IUCN Red List of Threatened Species, paragraph 5). Also included in this process is the ability to appeal against any current listings and the ability to review the Red List categories and criteria.

Causes For Species Becoming Threatened or Endangered

 The reasons that mammals have become threatened or endangered can be divided into four categories. The first three reasons are related to man's activities while the last reason is due to natural causes. The first reason that a  mammal may become threatened or endangered is due to control. "Control means the active destruction of a species of mammal by man because the species is believed to be a direct threat to man or his enterprises" (Brenner, Mujumdar, Rhoades, p. 243). Some examples of this can be seen in the gray wolf or mountain lion. Because man is so fearful of these animals, there are control programs in which state hunters and trappers are hired. Another control method used is the bounty system in which people receive money for proof that they have killed an undesirable animal. The bounty system has been around for a very long time, starting as early as 1683 in Pennsylvania when they began a bounty on wolves. "Pennsylvania alone paid $1,880,290 in bounties between 1915 and 1935" (Brenner, Mujumdar, and Rhoades, p. 243). Regardless of whether a control program was in effect or not, there are some species that were simply killed on sight because they were such a tremendous threat. There are several reasons for which man was threatened by these particular animals. One reason that man was threatened by these animals has to due with their livestock. Livestock to these animals were a new and plentiful food source. Mountain lions have been known to kill animals such as cattle, horses, goats, sheep, as well as pigs. Another reason for the control of these large mammals is because they are predators on game species. "Many people believe that the competition between hunter and predator can be confirmed by simple observations in which these predators are seen killing species which man hunts for food and sport" (Brenner, Mujumdar, and Rhoades, p. 244). Just because a predator is killing an animal that could be used for food or sport does not necessarily mean that the hunter would have been able to catch or kill that animal anyway. Another reason for control is due to the fear that an animal would attack and kill humans. Although this type of situation can happen they do not happen on enough of a regular basis so that people can justify the killing of these animals through control measures.

The second reason that animals have become threatened or endangered is due to exploitation. Exploitation is when an animal is used for financial or some other gain by man. One form of exploitation is the trapping of furbearing mammals. An example of the exploitation of animal for its fur was seen in the beaver in the late 1800's. The river otter was also another example of exploitation of animal for fur. This was due partly because of its fur and partly because it shared a habitat with the beaver. Another reason for the exploitation of animals was for food and hides. "This was particularly important during colonization and the spread of settlements" (Brenner, Mujumdar, and Rhoades, p. 245). The one species that extremely felt the effects of this was the black bear. Bear meat was a favorite because it was very tender and could be used in the winter time. Bear was also used because their oils could be used for cooking and for light.

The third reason that animals become threatened or endangered is due to changes in the environment. Usually these changes are brought about by man as he changes his environment to benefit himself. The first changes to occur in Pennsylvania were due to colonization. "Patches of the forest were opened for farming purposes, and homes were built from logs. Towns and cities were established, which led to the large metropolitan areas of today" (Brenner, Mujumdar, and Rhoades, p. 245). The lumbering of the forests is what had a major impact on many species especially in Pennsylvania. From 1896 to 1910, 225,000 acres were logged in the Upper Allegheny River Basin alone. Many rivers and streams became polluted because of the industrial development and many aquatic species disappeared from these areas as a result.

The last reason that animals have become threatened or endangered is due to biological factors. "Generally, as species approach the peripheries of their ranges, they become rarer because the habitat and environmental requirements of the species are not being fully met" (Brenner, Mujumdar, and Rhoades, p. 246). In some cases, their conditions become so extreme that the species become extinct. The bison was one example of an animal who reached the limits of its range in several states. Species that usually invade new areas due so in small numbers and then increase in size what they find that there is sufficient resources there for them to survive.

Pesticides

A pesticide is defined as "any chemical which is used by man to control pests" (Pesticides, paragraph 1) and each year over two billion pounds of pesticides are used, mostly for agricultural purposes. Although these pesticides improve the quality and quantity of the agricultural products that they are used for, if not used properly they can cause serious damage to livestock, pets, people, and especially wildlife and their habitats. After World War II, pesticide use skyrocketed and the number of deaths in the wild began to emerge. It took people over thirty years to realize how damaging these pesticides truly were and this was only because an author by the name of Rachel Carson wrote a book called Silent Spring which shed some light on this situation. Pesticides not only kill the things that they are supposed to but also kill innocent species as well. "Pesticides that harm or kill animals or plants not considered pest species are termed non-targets" (Contaminant Issues, paragraph 1).Animals can be affected by pesticides through many ways, some of which include acute poisoning, chronic poisoning, and secondary poisoning. Acute poisoning "takes place over a relatively short period of time, impacts a very localized geographical area, and is linked to a single pesticide" (Pesticides and Wildlife, paragraph 10). An example of an acute wildlife poisoning would include fish kills that are caused by pesticide residues that are carried into ponds, streams, and lakes due to surface runoff. "Chronic poisoning occurs over an extended period of time when there are pesticide levels not immediately lethal" (Pesticides and Wildlife, paragraph 11). Another type of poisoning is secondary poisoning which is when "an animal consumes prey species that contain pesticide residues" (Pesticides and Wildlife, paragraph 12).

Not all pesticides have negative effects on all wildlife. "The potential impact must be evaluated by simultaneously considering the availability of the pesticide or its degradation products, the toxicological properties of the pesticide, and the ecological characteristics of the exposure. The degree of direct impact a pesticide has on wildlife is determined by the sensitivity of a species to the chemical and the degree to which the species are exposed" (Pesticides and Wildlife, pg. 6). The are several questions that are used to evaluate the effects on wildlife including:

• What level of a pesticide residue or its breakdown product is introduced into a wildlife habitat through direct application or via the transportation of residues in air, water, food, or soil?

• How long does the pesticide remain in the environment?

• Is the animal or plant exposed to the pesticide by mechanisms including dermal contact, inhalation, or consumption of contaminated food or water?

• Is the pesticide capable of producing biochemical effects, illness, or death through either single or multiple exposures?

Although pesticides have the ability to cause negative effects on both plants and animals, there are some benefits to using these substances. Some of these benefits include the "reduction of insect-vectored and waterborne diseases, production of an abundant food supply, a positive impact on our balance of trade, nourishment for the world, and the reduction of soil erosion" (Pesticides and Wildlife, pg. 7). Because pesticides do have the ability to devastate plants and wildlife, there is a process in which pesticides must be registered. There are four steps to the registration process which include:

• research conducted by the manufacturer prior to its decision to pursue registration

• data submission report by the manufacturer to EPA

• EPA review

• a decision by the EPA either to register the pesticide or to deny registration

During the1950's and 1960's, there were several pesticides being used but the main pesticide that was being used during this time was DDT. DDT stands for dichloro-tricholoro-ethane and is an insecticide used to control insect-borne diseases. During World War II, DDT was used to prevent diseases such as typhus which was associated with the flea and malaria which was associated with the mosquito. "Because DDT remains in its toxic state for years, farmers enjoyed many seasons of protection from just a single spraying" (Facts about DDT, paragraph 2). Immediately following World War II, there was an increase of its use because farming became more specialized and the farmers needed it to keep their crops safe from the insects. This pesticide's popularity was due to the fact that is was cheap, available, safe, and thought to be very potent. "Between 1945 and 1955 alone, DDT production increased from 125 million pounds to 600 million pounds" (Facts about DDT, paragraph 3). In 1946, two scientists named Elmer Higgens and Clarence Cottam, published an article about the hazardous affects of DDT on animal species. They found that DDT had a tendency to accumulate in the fatty tissue of certain animals which was a major health risk. Although the effects of this pesticide could be seen in certain animals the use of DDT continued. It was not until two decades after the introduction of this pesticide that there were claims that DDT was responsible for declines in populations of birds. "Studies have revealed that eagles and other birds exposed to DDT had serious reproduction problems. Birds that had ingested DDT were found to lay eggs that were susceptible to shell thinning and those eggs rarely survived long enough to hatch. Because of this the eagle population plummeted" (Facts about DDT, paragraph 7). Because of these findings, the Environmental Protection Agency placed a ban on all domestic uses of the pesticide on June 14, 1972.

Although the use of DDT is now banned, there are many pesticides that are still being used today. The three main groups of pesticides that I will be discussing in the webpage will be insecticides, fungicides, and herbicides. "Insecticides are chemicals used to control insects" (Pesticides, p. 1). An insecticide may be able to kill an insect by just touching it or the chemical may have to be ingested to be the most effective. Insecticides vary in how long they can last. While some break down right away, others remain active for a fairly long amount of time. Insecticides called systemics are able to be absorbed, injected, or fed to a plant or an animal to provide protection against insects. Insecticides can be separated into two main categories. The first category is broad spectrum insecticides. These insecticides are used when there are multiple insects that are posing a problem. These insecticides work by attacking a system that is common to all of the insects such as the nervous system. The second category is the narrow spectrum and these insecticides are much more selective. There are three types of these narrow spectrum insecticides and they include chitin synthesis inhibitors, insect growth regulators, and pheromones.

The first narrow spectrum insecticide are the chitin synthesis inhibitors. They "interfere with the development and molting of immature insects causing their death" (Pesticides, p. 1). Chitin is the primary chemical in an insects body wall. The insect does not die right away, but the next time it tries to molt the result will be death.

The next narrow spectrum insecticide are the insect growth regulators also known as IGR's. These regulators "mimic the action of an insect's naturally occurring juvenile hormone. They interfere with certain normal processes and prevent immature insects from completing development into normal reproductive adults" (Pesticides, p. 1). The results due to these regulators include abnormal molting, twisted wings, loss of mating behavior, and sometimes death to embryos in eggs. The only disadvantage of these regulators is that they act slowly since they do not kill the insect until the next molting.

The next narrow spectrum insecticide are pheromones. Pheromones are "naturally produced chemicals used by animals to communicate to each other. These pheromones can be broken down into several categories. The first category is aggregation pheromones which attract many individuals together in one areas perhaps for food. The next category is sex pheromones and these are used by one sex to attract individuals from the other sex. The last category is trail pheromones which are deposited by insects that walk so that other animals are able to follow their path.

The second group of pesticides that I will discuss are fungicides. "Fungicides are chemicals used to control the fungi which cause molds, rots, and plant diseases" (Pesticides, p. 2). These fungicides work by coming into contact with the fungus. Because of this these fungicides are applied over a very large area in the hopes that it will come in contact with all fungus. Some fungicides can be systemic in that the plant can be injected or fed the chemical so that it moves throughout the plant killing the fungi. There are two approaches to the use of fungicides. One approach is developed to prevent the plant from getting a disease. These fungicides are used to protect the plants and prevent or inhibit fungal growth. The other approach kills the disease after it appears on the plant and is known as an eradicant. "Eradicants are less common than protectants because once the fungus is established in a plant, it is often difficult to destroy" (Pesticides, p. 3). These eradicants are most often used when protectants are not available, are not applied in enough time, or are too expensive.

The third group of pesticides that I will discuss are herbicides. "Herbicides are chemicals used to control unwanted plants. These chemicals are used to kill or slow the growth of some plants, rather than to protect them" (Pesticides,  p. 3). While some herbicides kill every plant they come in contact with, others kill only certain plants. There are two types of herbicides. The first type is nonselective herbicides which are toxic to all plants. "These herbicides are often used when no plants are wanted in an area. The second type is selective herbicides which kill some plants without causing damage to others. "Usually selective types will kill either broadleaved plants or grassy plants" (Pesticides, p. 3).

History of Whaling

Whaling began in the in the first few centuries A.D. by the Japanese. It is thought that by the end of the 17th century, the Japanese began to use nets to capture whales. This netting process involved the use of ten to twelve boats which positioned themselves in a semi-circle around the whale so that they could push the whale closer to shore. Once the whale was close enough to the shore, they would precede to kill the whale using harpoons. Over time, the Japanese developed their whaling technique and by the 20th century, whaling had evolved. Because of the technology the Japanese have received from Norway, they have been able to devastate one species of whale after another. The Japanese began "with chartering Norwegian vessels and crews to catch whales in Japanese waters, it then progressed to purchase of vessels from Norway and culminated in the building of Norwegian style whaling vessels in Japanese shipyards.

By the mid 20's the average catch was around 1,500 per year and many species of whale were being caught including the blue, gray, and humpback whales. This industrial whaling led to the exploitation of many species and because the populations of whales were decreasing very steadily, the Japanese just moved on to the next species in line when they found it hard to find a previous species they had been hunting.

Here are the catch records for every tenth years from 1920 to 1960

The Japanese used the whale mainly for oil which was sold to provide foreign currency. Although the Japanese were mainly interested in the oil, they did use the meat for food but most of the time is was discarded. During the course of this whaling, three major categories came to be known. The three categories are large-type whaling, pelagic whaling, and small-type coastal whaling.

The small-type coastal whaling is simply the whaling of smaller species of whale such as the minke whale and pilot whale which was regulated by the Japanese government. This type of whaling requires a license and provides the person with a boat so that they can capture various species of whales. Many of the species have quotas which are instituted by the International Whaling Commission but those species that do not fall under this protection receive quotas from the country itself. At the beginning of the small-type coastal whaling the Japanese used the nets to trap the whales in the bays but the development of the harpoon method changed all of this. By the 1920's they were using powered boats and harpoon guns which played a major role in the increased cruelty to these mammals.

Large-type coastal whaling is simply the whaling of the larger species of whales such as the the humpback whale and the blue whale. Over the years this type of whaling has made many changes including "new land stations, new whaling grounds opened further to the north and south, new whaling stations so the whalers could work winters in the south and summers in the north, the distribution of the species being taken, and the consolidation of the whaling companies into three large companies in the 1930's" (The Evolution of Japanese Whaling, p. 3).

Pelagic whaling is the process of whaling in the open seas. This type of whaling dates back to medieval times but it was the Norwegians who sent the their modern vessels to the Antarctic at the turn of the century. The Japanese did not partake in this venture until thirty years later because the oil market had collapsed and there were new regulations of whaling that were being instituted. But by 1941, Japan became one of the world's leading pelagic whaling nations. This type of whaling became so successful that it was producing more than all of the other whaling techniques combined.

Although the Japanese were the first to move in on this type of industry, American and British whalers discovered rich whaling grounds in 1820. By this time hundreds of whaling ships from the United States and other Western countries were whaling in the ocean off Japan. Because the United States and others were cutting into the Japanese profit from whaling they realized that if they were going to have to compete with the U.S. then they would have to modernize their way of doing things. They attempted to modernize to the American method but failed every time. It was not until they were introduced to the Russian method and later to the Norwegian method that their efforts showed some promise.

Although whaling has been around for a long time it has been regulated by the International Whaling Commission (IWC) since 1946. "The IWC gave its member nations quotas on the whales they wanted to hunt, based on negotiations and guesswork" (Whaling and Fishing, p.4). Because the IWC had placed these quotas too high, the populations of whale began to decline rapidly. It started with the blue whale and continued on down the line from the fin whale all the way to the sei whale. Although the IWC is made up of whaling nations, non-whaling nations have joined and now this organization has turned into a conservation-minded organization instead of a whalers' club. Because of this, in 1982, the IWC adopted an indefinite moratorium on commercial whaling which became effective in 1986. Becaue the IWC wanted to put a stop to commercial whaling many species seem to recovering from the years of damage that has been done. Because some of these species are beginning to prosper there is now some controversy within the organization because the whaling nations are trying to say that the species that are recovered need to be hunted to allow for the recovery of other species. Due to this recommendation by the whaling nations, in 1994, the IWC approved a Revised Management Procedure to reintroduce commercial whaling as stocks increase to certain threshold levels which are fifty-four percent of pre-exploitation levels. But because both sides of the organization could not come to an agreement the meeting ended in a stalemate. Although the IWC is here to provide protection for these animals, there are many loopholes in the moratorium which many countries are using to continue whaling. The first problem is that compliance with this moratorium is voluntary. If any member of the IWC does not agree with something they can protest and not abide by that rule. The second problem is that there are exceptions for aboriginal whaling which is whaling done by the American Eskimos. The third problem is that whaling is allowed if it is done for scientific research which some countries are using as just an excuse so they can keep making a profit. Another problem in protecting these mammals has to due with the issue of illegal whaling. Many countries report taking an average amount of species but instead are taking twice as many as the IWC had thought. Some countries are also building ships with false bottoms so they can carry more cargo than inspectors can see. Another problem with the IWC is that it really does not have any enforcement power. The only thing that can help is if the individual nation involved in the organization take action. Because whaling is such a major problem still, in 1994 the IWC set aside a huge area around Antarctica which would protect ninety percent of the whales feeding areas. Japan was the only nation to oppose this and continues to hunt whales on the basis of research.

"In 1972, the United States enacted the Marine Mammal Protection Act which prohibited commercial whaling by U.S. citizens" (Commerical Whaling and Whaling Conservation Policy, p.1). This act established a moratorium, with certain exceptions, of the taking of animals by United States citizens in U.S. waters and the importing of marine mammals and their products into the United States. This act defines the term take to mean "to harass, hunt, capture, or kill, or to attempt to harass, hunt, capture, or kill any marine mammal" (Office of Protected Resources,p.1). There are two levels of harassment that this act recognizes which include level A harassment and level B harassment. Level A harassment is "the potential to disturb a marine mammal or marine mammal stock in the wild" (Office of Protected Resources, p.2). The second type of harassment is level B harassment which is "the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption or behavioral problems, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering" (Office of Protected Resources, p.2). For more specific information please click on the link provided above.

Blue Whale

The blue whale belongs to the family Balaenopteridae of the suborder Mysticeti, order Cetacea. This type of whale is the largest living creature on Earth with a life expectancy of thirty-five to forty years and can be found in all the oceans of the world. They usually travel from the Tropics in the winter and to the northern and southern hemispheres in the summer. These whales are able to produce loud, low frequency moans that can travel over thousands of kilometers underwater. These moans enable the members of the group to communicate with one another over a very large distance. Blue whales can grow to be eighty feet in length with the females usually being larger than the male. Their skin has a gray and white mottled pattern which is unique to each mammal and has been used by researchers to identify individual whales. The hearts of these mammals weigh approximately one-thousand pounds and is the size of a Volkswagen bug car. Not only are these creatures the largest animal on earth, they are also the loudest, reaching 188 decibels which is louder than a jet. These animals feed by lunging into a group of krill or fish with their mouth wide open. As the water and fish run into the mouth, more than sixty throat pleats expand so that the whale's throat called the, gular pouch, forms a huge bag that extends from the snout to the navel. The whale then closes its mouth and forces the water past 270 to 390 pairs of baleen plates. These plates capture the food while letting the water go by. These whales will eat 2,000 to 9,000 pounds of plankton each day during the summer feeding season. Although these mammals live individually, they do swim in pairs to catch their food, by lunging from side to side using each other to block the escape of the prey. These mammals can dive for up to an hour going to depths of 350 feet. Not only can these animals dive very deep but they can also swim very fast going up to twenty miles per hour. Mating for these mammals occurs during the summer season and the female will give birth once every two or three years. The usual gestation period is around eleven months. The young nurses for seven to eight months and can gain up to 200 pounds a day. Although these animals are very large in size they do have predators such as the killer whales also known as orcas. These killer whales have been known to attack and kill the young of blue whales. But these killer whales are not the only threat of the blue whale. Although this whale was once thought to be too big and too fast too hunt, the introduction of factory ships and harpoon guns made the hunting of these animals more practical. Between the 1930's to 1960's this mammal almost became extinct because they were heavily hunted by man for their oil, baleen, and meat which had many uses ranging from soaps and cooking fat all the way to their liver being a source of vitamin A. By 1966, the International Whaling Commission declared the blue whale a protected species. Although they were protected by the IWC, it still took until June 2, 1970, four years later, to list them as endangered under the Endangered Species Conservation Act. Today there are approximately 500 true blue whales and there are no signs of recovery for reasons that seem to be unknown.

Although commercial whaling no longer poses a threat to these mammals, there are many other threats that these creatures have to face everyday. Some of these threats include "loss of habitat and other human activities, collisions with vessels, oil spills, changes in water quality, coastal development, as well as increasing noise created from the use of oceanic resources" (International Year of the Ocean, p.2). Fisheries may also affect these creatures. These nets are sometimes hazardous because the whales can get caught up in them and die. Fisheries can also affect these whales because both the fisheries and the whales are competing for the same food source. Another factor affecting the whales is the increased noise due to boat traffic. This noise is causing the whales to alter their behavior in that they no longer come close to shore to raise their calves. Another big factor is pollution. Not only are these pollutants staying in the whale's blubber for long periods of time but its also affecting the food that they need to survive.

Bald Eagle

"Two hundred and twenty years ago, on June 20, 1782, the bald eagle became an American icon when the Second Continental Congress decided to use its image on The Great Seal" (Bald Eagle Bounces Back After Decades of Persecution, p.1). Although Benjamin Franklin was less than pleased about using the Bald Eagle, Charles Thomson, the secretary of the Congress, substituted the bald eagle for the wild turkey because he thought that the "United States of America ought to rely on their own virtue" (Bald Eagle Bounces Back After Decades of Persecution, p.1) and the bald eagle was the best representation of this. Because this eagle is the symbol of our country, it is thought to be the most extensively studied North American bird. Although this bird is an amazing creature, Benjamin Franklin was not the only one who saw this animal in a negative light.

"To settlers, the eagle's seven-foot wingspan, fierce gaze, and crushing talons symbolized a competitor bent on depriving them of fish and game, and on depleting their livestock. They also killed the eagle for sport. Meanwhile Native Americans trapped and killed eagles to obtain ceremonial feathers" (Bald Eagle Bounces Back After Decades of Persecution, p.2). Not only did these things contribute to the decline of this animal, but human population growth and land clearing destroyed the prime habitat for these animals. Before European settlement, it was thought that there were between 250,000 to 500,000 bald eagles ranged across North America as late as the mid-1800's but by 1940, the rarity of this bird compelled Congress to pass the Bald Eagle Protection Act. This act outlawed the killing and disturbing of eagles, as well as the possession of eagle parts, including feathers, eggs, and nests. "The criminal penalty for disobeying this law is a maximum $5,000 fine or a one year imprisonment, or both, doubled for subsequent convictions" (Bald Eagle Protection Act, p.1). One place that played a major role in the depletion of this animal was Alaska. "After studies showed that salmon populations were not harmed by eagle predation, this law ended a bounty system in Alaska that claimed 128,000 eagles between 1917 and 1952" (Bald Eagle Bounces Back After Decades of Persecution, p. 3).

Just when the eagles were finally beginning to benefit from the Bald Eagle Protection Act, they became severely affected by the use of DDT. Although this pesticide was banned in 1972 it still caused much damage and by 1963 there were only 417 pairs of bald eagles found in forty-eight states. These eagles ingested large doses of the pesticide through their prey which became concentrated in the fatty tissues of these animals. This chemical caused the eggshells to thin and because of this, the egg was not able to support the weight of the mother and the eggs began to break causing a major decrease in this bird. Another negative effect of DDT was the fact that is was causing bald eagles to be infertile. Although they had protection under the Bald Eagle Act, that was not enough so in 1967, the bald eagle was listed as endangered in all areas of the United States. Today the bald eagle population is estimated to be around 100,000. Although these animals still face threats everyday, they are recovering. One problem still facing these creatures is a disease known as avian vacuolar myelinopathy which is a fatal neurological disease that showed up in eagles and other animals in 1994. Researches still have not determined the cause of the disease although they do suspect that it is some chemical of unknown origin. They do however believe that the eagles obtain the disease from eating prey that is infected. Although these birds have had to overcome devastation, they are recovering and on August 11, 1995, the U.S. Fish and Wildlife Service upgraded the status of the bald eagle in the lower forty-eight states to threatened.

These birds are magnificent creatures and can grow between thirty-five to thirty-seven inches long with a wingspan of seventy-nine to ninety inches. When these birds are young, they are brown and white but when they become an adult, between the ages of four and six, their feathers turn a blackish brown color and their head, neck, and tail stay white. These eagles can be found over most of the continent but more than half of this species live in Alaska. Although most of them live in Alaska they can also be found in Wisconsin where their nesting habitat is located. These nests are located in large trees near rivers or coasts because this makes food easily obtainable. A typical nest can be five feet in diameter and can grow to nine feet weighing as much as two tons. Although these animals are recovering there are still many causes of death some of which include:

• "fatal gun shot wounds by careless and ignorant recreational hunters, malevolent people, and those hunting them for their feathers and talons to sell on the black market.

• electrocution from taking off and landing on power poles when their large wings bridge two wires, resulting in fatal burns or heart attacks.

• lead poisoning from eating wounded deer, ducks, and other game which got away from the hunter and later died.

• young eagles ingesting poisoned meat that are used to bait wolves and coyotes.

• collisions with vehicles.

• starvation where food is scarce.

• eagles dieing of exposure because they have misjudged the altitude when snagging a fish and have ended up in the water" (History of Bald Eagles, p.2).

"In establishing a recovery program for the species in the mid-1970's, the Service divided the bald eagles of the lower forty-eight states into five recovery regions, based on geographic location" (Final Rule to Reclassify the Bald Eagle from Endangered to Threatened, p.3). These recovery plans were prepared by teams assigned to each of these specific regions and were composed of special experts. Each team came up with a set of goals and a list of way to achieve each of these goals. "The five recovery regions of their approved recovery plans are as follows: Chesapeake Bay, Pacific, Southeastern, Northern States, and Southwestern" (Final Rule to Reclassify the Bald Eagle from Endangered to Threatened, p.3). Many of these recovery plans have been funded by the Service and other Federal, State, and private organizations. The cost of these recovery plans for private and public organizations alone has been more than one million dollars each year for the past decade.

Leon Springs Pupfish

The Leon Springs Pupfish was first discovered in 1851 at Leon Springs which is a spring system near Fort Stockton, Texas. By 1938 the fish could no longer be found where it was first discovered and in 1958 Leon Springs went dry. These fish were thought to be extinct until they were collected in another spring around the same area in 1965. This fish was listed as endangered by the U.S. Fish and Wildlife Service on August 15, 1980. "The Leon Springs Pupfish declined because of habitat loss due to groundwater pumping, pollution, and competition and predation by introduced exotic species" (Pupfish,  p.1). The size of the Leon Springs Pupfish is about two inches in length. It is a small, robust, species that has a wider head and body than most other species of this fish. Breeding males are powdery blue-gray with fins of various shades of  yellow. Females are grayish-yellow or grayish-brown. It lives in natural spring fed marshes, pools, and slow-flowing waters where there is mud and aquatic plant roots. It usually feeds on algae and small invertebrates. These fish spawn throughout the year with females laying ten eggs per day. This spawning takes place at the bottom of their habitat and males are known to aggressively defend their territories. These fish have been observed doing "pit digging which is where the fish rests on the bottom of the pool and undulates their bodies to churn up the substrate to locate buried food" (Leon Springs Pupfish, p. 2).

It greatest problem was thought to be the sheeps-head minnow which was introduced through the carelessness of some passing bait salesman or fisherman. This particular minnow was a problem because it hybridized the species out of existence in the wild and now the only pure remaining Leon Springs Pupfish are located at the Dexter National Fish Hatchery and Technology Center in Dexter, New Mexico.

Small Whorled Pogonia

The small whorled pogonia (Isotria Medeoloides) is a member of the orchid family and was first described by Frederick Pursh in 1814 as Arethusa Medeoloides. In 1838 this orchid was placed in its own genus and recognized as Isotria Medeoloides. This plant is a herbaceous perennial which means that it is present all year long. It has slender, hairy, fibrous roots that radiate from a crown or rootstock. The five or six milky-green or grayish-green pointed leaves are seen in a whorl at the uppermost point of a smooth, green stem. A single yellowish-green flower stands in the center of the whorl of leaves. "An individual plant is usually single-stemmed, although two or more stems may occur; however, closely grouped double stems may in fact be two single plants. Because of the difficulty in differentiating double stemmed plants from closely neighboring plants, population estimates are often based on the number of stems, as opposed to the number of plants" (EPA: Federal Register, p.2).

This plant can be found in fairly young forests as well as in maturing stands of mixed-deciduous or mixed-deciduous/coniferous forests. The places where the small whorl pogonia is found share several common attributes. These common attributes include "sparse to moderate ground cover, a relatively open under-story canopy, and proximity to old logging roads, streams, or other features that create long-persisting breaks in the forest canopy" (EPA: Federal Register, p.2). This plant flowers from mid-May in the south to mid-June in the northern parts of its range. The soil in which this plant grows is usually composed of leaf litter and decaying material. Although this plant has a widely distributed range, there are three main population centers. The northern most concentration is centered in the foothills of the Appalachian Mountains. A second grouping is at the southern extreme in the Blue Ridge Mountains where North Carolina, South Carolina, Georgia, and Tennessee meet. The third grouping is concentrated in the coastal plain of Virginia.

The small whorled pogonia was listed as endangered on September 10, 1982. The first small whorled pogonia recovery plan was completed in 1985 and the goal was to locate and  protect thirty populations of at least twenty individuals each. Although this was a good start, the goal changed when new life history and site information was being reviewed. The first revision of this recovery plan came in 1992 and the new goal was developed by using the most current information that could be found. "The current recovery strategy is based on a multi-faceted approach of habitat protection and management, threat reduction, and environmental education" (EPA: Federal Register, p.4). This plan also detailed when this plant could be listed as a threatened status instead of an endangered one. This  plan states that "reclassification would be pursued when a minimum of twenty-five percent of the known, viable sites is permanently protected" (EPA: Federal Register, p.4). On October 19, 1993 all interested parties were asked to submit factual reports or information that might help to contribute a final rule regarding this plant. After review and consideration of all the information that was given, the Service stated that this plant should be reclassified as a threatened species. A species may be listed or reclassified as threatened or endangered due to on or more of the five factors which include:

• "The present or threatened destruction, modification, or curtailment of its habitat or range

• Over-utilization for commercial, recreational, scientific, or educational purposes.

• Disease or predation.

• The inadequacy of existing regulatory mechanisms" (EPA: Federal Register, pgs. 7-8).

The small whorled pogonia and its habitat continue to be vulnerable to development pressures throughout its range. The upland habitat in which this plant is found receives little protection when it is found on private land. Another factor responsible for the destruction of its habitat is residential and commercial development. "Housing developments, though not necessarily directly destroying habitat, may cause the alteration of habitat parameters by creating large, permanent openings in the canopy that in turn encourage denser under-story growth. Disturbance to populations through increased visitation from people and pets might also cause direct damage to plants, and eventually lead to a decline in affected populations" (EPA: Federal Register, pgs. 7-8).

Another factor contributing to the decline of this species is the potential collecting by wildflower garden enthusiasts who transplant these flowers to their gardens. Also a danger is the vandalism that occurs when a persons plant population is publicized and people take advantage and steal.

Another factor for this plant is the threat of white-tailed deer and invertebrates, including slugs and carmel crickets. "Increasing development pressure near small whorled pogonia populations results in the concentration of deer onto smaller parcels of woodland and may decrease local hunting pressure on suburban deer populations. As the local deer herd increases and is forced onto less land, there is a greater likelihood that these plants will get destroyed" (EPA: Federal Register, p.8).

Houston Toad

The Houston toad was discovered in 1953 and was labeled as an endangered specie in 1970. The Houston toad is two to three and a half inches long and has a life span of only two to three years. They vary in color from light brown to gray or purplish gray. Males have a dark throat which appears bluish when distended. The Houston toad is a terrestrial amphibian associated with deep sandy soils. Because this toad is not very proficient as a burrower, loose soils are required so that they can dig. They borrow into the sand as a way to protect themselves against the cold weather in the winter time and hot dry conditions in the summer time. Another source of protection that these toads use is the enlarged glands that they have on the side of their neck and behind there eye. These glands secrete a poison that gets smeared in the mouth of a predator. This poison inflames the mouth and throat causing nausea, irregular heartbeat, and even death. The vegetation that is located in their habitat can be described as pine or oak woodland or savannah. To breed, this toad requires still or slow-flowing bodies of water that persist for at least thirty days. The water source should be located within one half to three quarter miles of a toads foraging habitat. The males call the females to the breeding pond with a high, clear trill that lasts an average of fourteen seconds. Most breeding activity takes place in February and March and is stimulated by warm evenings and high humidity. The female lays her eggs as long strings in the water, where they are fertilized by the male as they are laid. The eggs hatch within seven days and turn into tadpoles between fifteen and one hundred days depending on the water temperature. These young toads are only one-half inch long when they turn into a tadpole. Males generally breed when they are only one year but females wait until they are two. The Houston toad is a year round resident where found in parts of Texas. The toad's presence is most notably noticed when it is heard calling for the female during the breeding period. Their diet consists mainly of insects and other invertebrates. There are two methods that they use to capture their food. One method is sit and wait and the other is active search. "For the sit and wait method, they first dig a small depression in the soil with its powerful hind legs. The toad then rests in the depression and scans the surrounding area for movement. When prey is detected it leaps forward and takes the prey into its mouth" (Houston Toad, p. 1).

Although the Houston toad is recognized as being endangered, there are still many threats facing this amphibian today. Habitat loss and alteration are the most serious threats facing the Houston toad. The alteration of their natural wetlands for urban and agricultural uses are eliminating the breeding sites which is making it hard for the numbers of these frogs to increase. Another danger is the conversion of a wetland into a permanent pond. This not only "makes them more vulnerable to predation by snakes, fish and other predators; but also increases competition and hybridization with closely related species" (Houston Toad, p.3). Drought also plays a role in the decline of this species because it may result in the loss or reduction of breeding sites. Even if they are able to produce offspring the chance that they will survive decreases because of this dry environment. The clearing of native vegetation also plays a role in the decline because this reduces the quality of breeding, foraging, and resting habitat, and increases the chances of predation and hybridization. When they remove the native grassland they replace it with sod-forming grasses which makes it hard for them to move around freely and also inhibits them burrowing for protection. Another big factor in reducing the numbers of these frogs are the red fire ant. These fire ants kill young toads moving out of the breeding pond and onto land. They also have a great impact in the food that these frogs eat causing even more of an impact on their recovery. Although people may not want to help in the recovery for this frog because it is of little economic value it does have a function which is the fact they limit insect populations so that they do not become too overabundant. To combat the problem of habitat loss, which seems to be the biggest threat at this moment, organizations have been purchasing land for these creatures to be able to recover.

American Crocodile

"Crocodiles are often referred to as living fossils because they have the same basic appearance and lifestyle that they had nearly 200 million years ago during the age of dinosaurs" (AMNH-Expedition, p. 1). The American crocodile is the second most widely distributed of the New World crocodiles. Its range includes "the tip of Florida, both the Atlantic and Pacific coasts of southern Mexico, Central America, and northern South America, as well as the Caribbean islands of Cuba and Jamaica" (Species Accounts, p. 1). Although these crocodiles can be found in many places of the world, in North America they are only found at the southern most tip of Florida where their population is estimated to be around 500. The American crocodile's habitat mainly consists of freshwater or the saltwater sections of rivers, coastal lagoons, and mangrove swamps. This crocodile is a very large species where males can have a maximum length of fifteen feet. These animals feed when there is opportunity and most of this feeding is done at night. They can feed on anything from fish and crabs to birds and small animals. This crocodile is thought to be the most adaptive when it comes to nesting although they do prefer secluded areas. Although these reptiles prefer hole-nesting, they will form mound-type nests if the other form is not practical. They typically nest during the annual dry season so that their eggs will hatch during the rainy season. The young crocodiles need to survive at least two years for them to be able to fight off predators. However, some of these animals are not that lucky and can be eaten by a number of other animals including raccoons, birds, crabs, and even other crocodiles.

 On September 25, 1975 the American crocodile was designated as endangered throughout its entire range. The listing is due to the fact that "this species produces a commercially valuable hide and the principal reason for past declines in population size can be attributed to the extensive commercial overexploitation that occurred from the 1930's into the 1960's" (Species Accounts, p.2). Some of the current threats facing this reptile are habitat destruction and in some areas continued hunting. "Dams built to supply water for homes, cities, and farms greatly reduce the flow of fresh water from Lake Okeechobee into Florida Bay and as a result the salt content of the bay is rising dramatically" (AMNH-Expedition, p.1). Although the adult crocodiles can tolerate such an environment, the babies cannot. They need fresh water to survive. Because of these threats a private program to maintain a captive breeding stock for conservation purposes is underway.

I would also like to discuss the difference between crocodiles and alligators since many people have a tendency to mix the two up. On both sides of the lower jaw of crocodiles, the fourth tooth from the front of the snout is visible when the animals mouth is closed. When an alligators mouth is closed, you cannot see any of its teeth. Alligators also have a broad snout whereas crocodiles have a narrow one. Alligators have a darker coloring than crocodiles. Alligators also have a tendency to bellow whereas the crocodile is far less vocal but can be heard at times.

Captive Breeding and the Reintroduction of Endangered Species

As extinction increases, biologists are seeking methods for preserving endangered species. Captive breeding is one method used to preserve some important species. "Captive breeding focuses on the reproduction of rare animals in captivity" (Captive Breeding, p.1). This method enables species to reproduce without having the normal threats that they would have in the wild. If wild populations of species reach critically low numbers then it is sometimes necessary to reintroduce captive species into the wild. Once a species in captivity reaches a self-sustaining population level then they are reintroduced back into the wild in an area that was part of its range. If the species cannot be released in its range than a more suitable habitat will be found.

Although the idea of saving populations of animals is nice, it is not always practical or feasible. Several problems arise when a species reaches a very small population size. One problem is the loss of genetic variability. "When a population gets below about 500 breeding individuals, the amount of genetic variation is reduced, and this can eventually diminish the species capacity to adapt to environmental changes" (Captive Breeding and Reintroduction, p.2). One example of the loss of genetic variability is the cheetah.

Another problem that species face is inbreeding. "Populations that fall below about fifty breeding individuals are forced to breed with close relatives which can lead to depression of fitness which includes problems such as decreased fertility, high juvenile mortality, and birth defects" (Captive Breeding and Reintroduction, p.3). An example of this is seen in the California condor which was down to less than thirty individuals.

Another problem seems to be hybridization. "This can be a significant problem because species hybrids cannot be protected under the Endangered Species Act. An example of this hybridization occurs between the red wovles and gray wolves which have turned out to be wolf/coyote hybrids.

Another problem is selective breeding which can become a danger when animals are in captivity for long periods of time and when there is an establishment of traits that are desirable in captivity but not in the wild. There is also a danger of animals becoming domesticated because they are so dependent on human caretakers. An example of this can be seen in the golden lion tamarin who was released into the wild and failed to respond to danger or to predators.

One program aimed at preserving the lives of endangered and threatened species is the Species Survival Plan Program. This program is run by the American Zoo and Aquarium Association (AZA) and their goal is to help ensure the survival of selected wildlife species. This mission will be implemented using a combination of the following strategies:

• "Organize scientifically-controlled managed breeding  programs for selected wildlife as a hedge against extinction

• Cooperate with other institutions and agencies to ensure integrated conservation strategies

• Increase public awareness of wildlife conservation issues, including development and implementation of education strategies at AZA-member institutions and in the field

• Conduct basic and applied research to contribute to our knowledge of various species

• Train wildlife and zoo professionals

• Develop and test various technologies relevant to field conservation

• Reintroduce captive-bred wildlife into restored or secure habitat as appropriate and necessary" (AZA, p.1).

"This program began in 1981 and each plan manages the breeding of a species in order to maintain a healthy and self-sustaining  population that is genetically diverse and demographically stable" (AZA, p.2). There are currently 106 plans covering 161 individual species. For a species to get selected for this program it must meet certain criteria. Most of these species are considered endangered or threatened in the wild and have the interest of professionals who want to dedicate their time to preserve the species. Examples of these type of animals would be the giant panda or the lowland gorilla. New species must be approved by the appropriate AZA Taxon Advisory Group (TAG) or by the AZA Wildlife Conservation and Management Committee. Each of these species has a designated coordinator who is responsible for managing their everyday activities. Management committees are also composed so that they can assist the coordinator in their conservation efforts. Each committee is composed of elected experts who help with population management, research, education, and reintroduction. Each specie has a master plan that outlines the goals for the population. "Breeding and other management recommendations are made for each animal with consideration given to logistics and feasibility of transfers between institutions as well as maintenance of natural social groupings" (AZA, p.3). These master plans often include recommendations not to breed animals because they do not want to have to many of one population in a small facility. Although reintroduction is not always practical for all animals, several species have been brought back such as the red wolves and black-footed ferret.

Zoos are another resource used to help preserve the number of very important species. "There are roughly 500,000 mammals, birds, reptiles, and amphibians in captivity in zoos throughout the world" (Captive Breeding, p.5). The role of zoos for species conservation is limited by space and expense. "It is estimated that if existing zoos were used exclusively for captive propagation of threatened species, a maximum of about 900 species of vertebrates could be kept alive in captivity" (Captive Breeding, p. 5). Although many zoos are attempting to increase the numbers of these animals only 26 of 274 species of rare mammals in captivity are self-sustaining. This number does not seem very promising but the "improved management of the genetics of small captive populations is beginning to make propagation more successful by eliminating some of the problems associated with inbreeding. The International Species Inventory System now keeps genealogical information on individual animals of 2,500 species of mammals and birds kept in 326 zoos in Europe and North American. This makes it possible to arrange mating by computer in order to minimize problems caused by inbreeding" (Captive Breeding and Reintroduction, p.5).

Shogren, J.F. & Tschirhart, J. (2001). Protecting Endangered Species in the United States. Cambridge University Press.

Beatty, R.G. (1973). The DDT Myth. New York: The John Day Company

Raup, D.M. (1991). Extinction: Bad Genes or Bad Luck? New York: W.W. Norton & Company

Brenner, F.J., Majumdar, S.K. & Rhoads, A.F. (1986). Typehouse of Easton

The IUNC Red List of Threatened Species. (n.d.). Retrieved October 22, 2003 from http://www.redlist.org/info/introduction.html

Ventana Wilderness Society California Condor Life History. (2003). Retrieved October 22, 2003 from http://www.ventanaws.org/condhist.htm

Dinosaur Extinction Page. (1997). Retrieved October 15, 2003 from http://web.ukonline.co.uk/a.buckley/dino.htm

National Museum of Natural History. (n.d.). Retrieved October 15, 2003 from http://www.nmnh.si.edu/paleo/blast/k_t_boundary.htm

Fish. (n.d.). Retrieved October 20, 2003 from http://darter.ocps.net/classroom/klenk/fish.htm

Dinosaur Extinction-Enchanted Learning Software. (2003). Retrieved October 15, 2003 from http://www.enchantedlearning.com/subjects/dinosaurs/extinction/

IUNC. (2003). Retrieved October 22, 2003 from http://www.iunc.org/themes/ssc/index.htm

Pesticides-About Pesticides. (2003). Retrieved September 21, 2003 from http://www.epa.gov/pesticides/about/

The Devonian Period of the Paleozoic Era. (2003). Retrieved October 20, 2003 from http://www.science501.com/PTDevonian.html

Devonian Sea Monsters and Creatures. (n.d.). Retrieved October 20, 2003 from http://www.museum.siu.edu/Lincoln_Middle/Devonian%20Sea%20MonstersCreatures

Cartilaginous Fish. (n.d.). Retrieved October 20, 2003 from http://www.amnh.org/exhibitions/hall_tour/spectrum/17.html

The Evolution of Mammals. (1998). Retrieved October 19, 2003 from http://www.enchantedlearning.com/subjects/mammals/Evolution/shtml

Pesticides Endangered and Threatened Species. (2003). Retrieved September 21, 2003 from http://www.epa.gov/espp/coloring/especies.htm

Environmental Quality Program. (2001). Retrieved Ocober 21, 2003 from http://contaminants.fws.gov/Issues/Pesticides.cfm

General Statistics for Endangered Species. (2003). Retrieved October 21, 2003 from http://ecos.fws.gov/tess_public/TessStatReport

The Whaling Controversy. (n.d.). Retrieved October 29, 2003 from http://www.geocities.com/Athens/Styx/9189/whaligcon.html

The Evolution of Japanese Whaling. (2001). Retrieved October 29, 2003 from http://www.whalesci.org/human/japan-history.html

Hampton Life. (1999). Retrieved October 29, 2003 from http://www.hamptonlife.com/history_whaling.html

Oceans Campaign-Whaling. (n.d.). Retrieved September 21, 2003 from http://archive.greenpeace.org/oceans/whaling/whalingjapan.htm

Pesticides-Benefits and Risks. (2003). Retrieved October 22, 2003 from http://msucares.com/pubs/publications/pub1962.htm

Natural Pesticides from Plants. (1997). Retrieved October 22, 2003 from http://www.hort.purdue.edu/newcrop/preceedings1990/v1-511.html

Pesticides and Wildlife. (n.d.). Retrieved October 22, 2003 from http://www.r6.fws.gov/feature/pesticid.html

Pesticides. (n.d.). Retrieved October 22, 2003 from http://www.pestcontrolcanada.com/pesticides.htm

Pesticides and Wildlife. (n.d.). Retrieved October 22, 2003 from http://www.btny.purdue.edu/Pubs/PPP/PPP30.html

The Triassic Period. (n.d.). Retrieved October 22, 2003 from http://www.ucmp.berkeley.edu/mesozoic/triassic.html

Chicxulub an the Cretaceous Tertiary Boundary. (n.d.). Retrieved October 20, 2003 from http://www.lpl.arizona.edu/SIC/impact_cratering/Chicxulub/Chicx_title.html

Blue Whale. (n.d.) Retrieved October 29, 2003 from http://www.kidsplanet.org/factsheets/blue_whale.html

Blue Whale. (1999). Retrieved October 29, 2003 from http://www.state.ak.us/local/akpags/FISH.GAME/wildlife/geninfo/game/blue.htm

Blue Whale. (2003). Retrieved October 29, 2003 from http://www.enchantedlearning.com/subjects/whales/species/Bluewhale.shtml

Blue Whale. (n.d.). Retrieved October 29, 2003 from http://encarta.msn.com/encyclopedia_761579739/Blue_Whale.html

Bald Eagle Protection Act. (n.d.). Retrieved October 30, 2003 from http://ipl.unm.edu/cwl/fedbook/eagleact.html

History of Bald Eagle. (2003). Retrieved October 30, 2003 from http://www.baldeagleinfo.com/eagle/eagle11.html

Bald Eagle Q&A. (n.d.). Retrieved October 30, 2003 from http://www.we-energies.com/environment/bald_eagle_qa.htm

Bald Eagle Bounces Back. (2003). Retrieved October 30, 2003 from http://news.nationalgeographic.com/news/2002/06/0620_020620_baldeagle.html

Final Rule to Reclassify the Bald Eagle. (1995). Retrieved October 30, 2003 from http://endangered.fws.gov/fr95580.html

The Leons Springs Pupfish. (n.d.). Retrieved October 30, 2003 from http://www.nativefish.org/Articles/leons.htm

Leon Spring Pupfish. (n.d.). Retrieved October 30, 2003 from http://www.tpwd.state.tx.us/nature/endang.animals/leonspf.htm

EPA: Federal Register. (2003). Retrieved November 1, 2003 from http://www.epa.gov/docs/fedrgstr/EPA-SPECIES/1994/October/Day-06/pr-7.html

Endangered-Houston Toad. (n.d.). Retrieved October 31, 2003 from http://ndngrd.com/endangered/houstontoad.html

Houston Toad. (n.d.). Retrieved October 31, 2003 from http://www.enature.com/fieldguide/showSpeciesRecNum.asp?recnum=AR0645

About Condors. (2002). Retrieved October 22, 2003 from http://www.terrafocus.org/pages.cfm?pageID=27

Captive Breeding and Reintroduction. (n.d.). Retrieved November 1, 2003 from http://darwin.bio.uci.edu/~sustain/bio65/lec15/b65lec15.htm

American Zoo and Aquarium Association. (2003). Retrieved November 1, 2003 from http://www.aza.org/ConScience/ConScienceSSPFact/

American Crocodile. (n.d.). Retrieved November 2, 2003 from http://www.kidsplanet.org/factsheets/american_crocodile.html

Species Accounts. (n.d.). Retrieved November 2, 2003 from http://www.flmnh.ufl.edu/natsci/herpetology/act-plan/cacut.htm

AMNH-Expedition. (1996). Retrieved November 2, 2003 from http://www.amnh.org/nationalcenter/Endangered/croc/croc.html