From Student LF:

Does the extinction of animals affect the human race? If yes how?

Over time, ecosystems change and, with change, animal and plant extinctions occur as a natural consequence. However, ecosystem changes normally occur over long periods of time – hundreds to thousands to tens of thousands of years. Human activities, particularly since the time of the industrial revolution in the late 1800’s, have undeniably and rapidly altered natural ecosystems to the point where animals and plants within habitats across the globe face daunting survival challenges.

If you just look at the region in which we live, incredible changes have occurred. 500 years ago, Maryland was over 90% forested and boasted species like Passenger Pigeons, American chestnut, Red-cockaded woodpeckers, wolves, bison, wild turkey, elk, bald eagles, cougars and black bear. Earlier in this century, the woodlands had been cut to 20% and many of the predators were driven out of the state. Wild turkey and black bear were essentially gone from the state as well. Supposedly miracle pesticides, particularly DDT, infiltrated the ecosystem and destroy clutches of eagle and osprey eggs – bringing these birds to the brink of extinction. Eventually this chemical was banned and these birds have both made strong comebacks. A fungus spread by an introduced beetle, which traveled into the country through the trade of wood products, wiped out the dominant tree species in our forest, the American chestnut. In recent decades, as the forests have returned, black bear and turkey have repopulated or been restocked in the state but passenger pigeons are gone forever and most of the large animals that have disappeared are unlikely to return because the existing habitat probably cannot support them and, in general, most people aren’t comfortable with large predators in their backyards.

Today, the animals and plants within three of Maryland’s main habitat types are threatened by various human activities: wetlands – through drainage for development, exotic invasive species and pollution, forests – through fragmentation and exotic invasive species, and native meadows – through commercial, residential and agricultural development and exotic invasives. Development around the region has essentially created a monoculture of species that do well around humans – many of which are not even native – European starlings English sparrows, cabbage butterflies, pigeons, crows, robins, rats and gray squirrels. The native habitats and their representative species are funneled into small patches of forest, wetlands and natural fields.  The deer overpopulation problem is a direct result of eliminating large predators and building developments within the deer’s natural habitat – forcing deer to utilize lawns and other areas to feed. You can see how our determination to rid the area of predators has affected us today. People get injured and even killed in accidents with deer. The monetary damage created by deer collisions and depredation on landscape plants is substantial.

The things I describe that have happened in our area are happening in other areas of the world. In some cases, such as tropical forests or coral reefs, the number of plant and animal species affected by habitat loss and changes are far greater than those affected here. Certainly, these changes affect us. Many species of animals and, particularly, plants, have important medical and food values to humans. Each species plays a role within its environment and eliminating a species from or introducing a new species into that environment can have unforeseen consequences to the habitat as a whole. Plants perform multitudes of important functions like creating oxygen and food in the form of sugars. Their roots and leaf canopies help stabilize soils, capture nutrients and prevent flooding. Certain plants do each of these things in different ways and a species’ particular specialty may be unique within an ecosystem and, if lost, might negatively affect countless other species within that environment.

Cultures utilize animals as important symbols. Grizzly bears, which are pictured on the California State Seal, are no longer found in California. Panamanian golden frogs, the national animal of Panama, are functionally extinct in the wild – the victim of an imported fungus that destroys the frogs’ sensitive skin. As part of the Project Golden Frog, The Maryland Zoo maintains a population of captive golden frogs – which may be utilized to repopulate habitats if the Chytrid fungus can be controlled or eliminated from the region. Our own national symbol, the bald eagle almost died off. Other lesser-known animals like mussels, clams and oysters are disappearing around the world. These animals provide important water filtration functions and decline rapidly when water pollution overwhelms their capacity to clean the water. Who knows how many important insect pollinators; beneficial insect predators and other important invertebrates have been lost to science – in some cases, perhaps, before they have even been discovered!

Do the changes that are occurring in the world now, for example climate change, increase the rate of animal extinction?

This is definitely possible. Some scientists believe that even a small rise in the average yearly temperature of the earth could alter some ecosystems in such a way to put stress on at least some of their fauna and flora to adapt to the changes or be phased out. Of course, these changes might benefit other organisms, which might ultimately balance the equation even though the species composition would change. Scientists are very concerned about polar bears and other species dependent on the polar ice cap. As temperatures warm overall, the ice cap will likely shrink in size creating less feeding habitat for the bear and making in more difficult for young bears to get on and off the ice cap in fall and spring. While this is the obvious example, other scientists think that the chytrid fungus problem mentioned for frogs might, in part, be related to climate change. Desertification of areas, more intense storm activity and the flooding of coastal areas may also be potential environmental stressors that might result from climate change.

What animals should we be mostly concerned about losing? Why?

I think we tend to overlook the less noticeable animals and plants. Most of people’s focus tends to be on the characteristic mega-fauna like pandas, elephants and tigers. They are exciting, often cute or inspirational, serve important roles within their ecosystems and also serve as great ambassadors for environmental concern and conservation, but for each one of these animals there may be a multitude of lesser-known animals and plants that are also in trouble and may even serve a more vital purpose within the interrelationships of their ecosystem.

Keystone species are animals that serve a particularly important role within an ecosystem. In all healthy ecosystems, organisms that produce food, i.e. the plants, constitute the base of the food pyramid and make up the majority of the biomass (overall weight of the living things in an ecosystem) of the ecosystem. Primary consumers, plant eaters, make up the next tier in the pyramid and the next largest biomass constituent. In most ecosystems, small herbivores, including pollinators, like insects, small birds and rodents make up far more of the overall biomass than large herbivores like elephants and wildebeest. Therefore, the loss of important constituents in either the producer or small primary consumer segments of the ecosystem can be far more detrimental than the of the loss of one or more of the mega-fauna. Not to say the mega-fauna are not important. Elephants are often considered keystone species in the African Savannah because they are capable of knocking down trees, which allows other animals to browse on leaves that they normally could not reach and also allows more grasses to grow for the multitude of grazers to utilize. They are also good at getting to underground water in severe droughts. But people tend to overlook the less flamboyant cogs in the system.

What organizations today are fighting animal extinction and trying to preserve the species on the verge of extinction?

Zoos certainly play their part. The Association of Zoos and Aquariums (AZA) runs a program known and the Species Survival Plan. This program is described in detail in the conservation section of our website and on the AZA website ( There are many other organizations involved in this issue ranging from government agencies (MDDNR and US Fish and Wildlife,), legal organizations (Defenders of Wildlife), species or taxon (ie primates, big cats) specific organizations (Project Golden Frog, The Mountain Gorilla Veterinary Project, The International Rhino Foundation, Polar Bears International), habitat purchasing organizations (The Nature Conservancy) and International organizations (World Wildlife Fund, International Union for Conservation of Nature (IUCN), CITES (Convention on the International Trade of Endangered Species).

Why is it important to conserve rare breeds?

Do you mean rare species or rare breeds of say cattle etc? A breed is a distinct variation within a species that has characteristics that can be replicated but whose individuals can also breed with other breeds within the species. Rare breeds of livestock are important because they may contain characteristics that might make them more resistant to diseases than the highly-specialized breeds that we use to produce mass quantities of say milk or beef.

What can people do or change about their everyday lives to help slow down to rate of animal extinction?

Certainly conserving resources through reducing, re-using, recycling and carpooling helps lessen the human impacts on natural ecosystems. Using less energy reduces the need for natural resources and may save habitat. By being a careful consumer and not buying products from threatened or endangered species or ecosystems and by supporting organizations that effectively champion this cause. Volunteering at a local nature center or participating in local clean-up events also are extremely valuable contributions.

But, by being interested in this subject, you are probably in touch with a lot of these things. The hardest part is getting others that do not have this same interest to understand the value of wildlife and take steps towards changing their habits. This can be very difficult to do, but is worth pursuing. Starting or joining a school-related group championing this cause and staffing a booth at school functions may be a good way to inform your peers. Doing the same at community events steps it up a notch and informs members of your community of the issue. Attending local land use and community planning meetings to monitor the impacts of projects on local habitats is another big role that citizens can play.

  • kim

    very well worded. well done. i used this info for a reasurch project i must do