Amphibians are cold-blooded, smooth-skinned vertebrates, such as frogs
or salamanders. The belong to the class Amphibia. Amphibians characteristically hatch
in or near the water as aquatic larva with gills, and then
transform into adults having air-breathing lungs. The bodies of amphibians dry out
easily, so they are usually found near water or in damp areas throughout their lives.
Reptiles are cold-blooded vertebrates, such as snakes, lizards, crocodiles, turtles, or dinosaurs. They belong to the class
Reptilia. They have an external covering of scales or horny plates and breathe by means of lungs. Reptiles usually lay eggs and their
young have lungs when they hatch. Reptiles may live on land or in the water, but those that live in the water must come
to the surface to breathe air.
Herpetology is the scientific study of amphibians and reptiles. This
includes the life history, habitats, feeding and reproductive habits,
and diseases of amphibians and reptiles. The study of animals and their
interactions with their environments can have an effect on people far beyond
academic circles. Herpetologists observe, collect data and connect what they've
seen with what it means. For example, they observe that habitat degradation is a big problem for amphibians and reptiles. It disrupts
their life stages, makes it harder for them to find food, and makes them more likely to get sick.
For example, in 1995 some middle school students in Henderson, Minnesota collected frogs from their local ponds for a science
project. They found that half of the frogs they collects had major deformities, such as 5 or more back legs or no back legs at all.
Scientists from all over the country began to study the causes and found frog deformities in many other places as well.
There have been many explanations, from too much ultra-violet light, to chemical contamination in the water, to epidemics of
amphibian parasites. However, every one of the possible causes can be traced back to human alteration of the environment.
The amount of ultra-violet light reaching the surface of the Earth has increased because of the thinning of the
ozone layer in the upper atmosphere that usually blocks ultra-violet light. That thinning has been tentatively linked to the high
amounts of atmospheric pollution from factories, cars and other machines. The chemical contaminants in the water come from
industrial and agricultural waste water and run-off. Finally, the destruction or alteration of habitat causes changes in the number and
types of organisms that can live there. Loss of wetland habitat to human building and agricultural projects has created environments
that are very comfortable and friendly for some parasites, like the Ribeiroia ondatrae fluke. This has led to a population
explosion of Ribeiroia, which infect more frogs and raise the number of
deformed frogs.
Because amphibians are so sensitive to changes in their
environments, people have begun to use amphibian health as a way to measure the health of the environment.
What is happening to frogs today, could be happening to humans tomorrow. The
health of frogs serves as an early warning system to tell people to make changes
that will protect their own health before the damage becomes severe.
