Amphibians |
|
Amphibians were the first vertebrates to leave the water to live on land. This occurred about 360 million years ago. Over the next 125 million years, amphibians faced little competition from other vertebrates and evolved into as many as 15 major groups. With the coming of reptiles, and then birds and mammals, the amphibian groups declined to the three of today - 1) frogs and toads, 2) salamanders, and 3) caecilians (a group of worm-like creatures that live in the tropics). Amphibians had to adapt to a life on land as compared to living in the water. Without the buoyancy of the water, their legs had to adapt to not just move the body but also to support it. The gills used for breathing underwater were replaced by lungs and moist skin. The skin had to change to be able to minimize the loss of water through evaporation. Their adaptations have not been entirely successful as most amphibians must return to water to breed. Those that don't still need at least a moist environment in which to lay their eggs. As its name implies, an amphibian is amphibious living both ("amphi") modes of life ("bios"), -- part of the time on land and part of the time in the water. Since their mucous-covered skin still loses a lot of water, most amphibians must live in either a moist habitat (in a wetland or underground) or have a nocturnal lifestyle. Amphibians are uncommon in deserts and in marine environments (due to the dessicating effects of the water's high salt concentrations). Amphibians are "cold-blooded" which means their body heat is obtained from their environment. This adaptation makes them not well-adapted for any activity in cold environments such as the tundra, alpine areas, and even the winter months in temperate regions. In northern New England, most amphibians are dormant during the winter. Basking in a warm spot can help amphibians to remain active even at quite low temperatures. Many predatory fish, birds, mammals, reptiles, and even some insects include amphibians in their diets. In general, amphibians are eaten in large numbers even though some produce a skin toxin to discourage predators and others can move away from a predator quickly (frogs jumping). Amphibians are also predators with a diet consisting of a wide array of invertebrates and even some small vertebrates. Algae and other plants are part of the diet of some species of amphibians in their larval stage. The large number of eggs produced by many species of amphibians is an adaptation to offset the numbers eaten by predators. The probability is high that at least a few will survive to reach the adult stage and carry on the survival of the species. The following species could possibly be found in this area: |
Frogs and Toads
|
Salamanders and Newts
|