Amphibian Diversity Amphibians Term amphibian means double life

Amphibian Diversity

Amphibians • Term “amphibian” means “double life. ” • During their life cycle, they live both in the water and on the land – When immature, they are fishlike and breathe through gills – As adults, they live on land breathe through lungs and moist skin

Main Characteristics • 3 main groups: – Frogs and toads - Anurans – Salamanders and newts – Urodeles – Legless amphibians - Caecilians • Ectothermic – Cold-blooded vertebrates whose body temperatures adjust with the outside environment

Vs. Frogs have: smooth or slimy skin strong, long legs and webbed hind feet two bulging eyes Toads have: warty and dry skin stubby bodies with short hind legs parotid glands behind eyes lay eggs in clusters small teeth in upper jaw lay eggs in long chains no teeth

Salamanders & Newts • Have long bodies, tails, and short legs • Only 440 species in the world • Seven species reside in Wisconsin, but most go entirely undetected by humans • Generally, the adults live on land return to the water only for breeding

Metamorphosis

Main Characteristics, cont. Adult amphibians live in moist areas. Why? – In addition to breathing through lungs, they also breathe through their skin – They have thin, semi-permeable skin that needs to remain moist – Their eggs lack hard outer shells and must be deposited or laid in water

Habitats for frogs and toads forests grasslands lakes, ponds, marshes rivers and streams

Where do they go in winter? • Most frogs bury themselves in the muddy floor of a lake or pond during the winter; whereas toads tend to dig down into the ground below the frost line. • Hibernation: a winter sleep during which time the animal can live on food stored in its body. The oxygen it needs can pass through its skin. • A few species in Wisconsin actually freeze solid during the winter. – Their body creates an “anti-freeze” that saturates their cells so they don’t freeze, although their breathing and heart stops

Amphibians’ Defenses • Hiding - best defense is to remain undetected by blending in or by hiding under rocks, logs, or underground

glass Frog Red-eyed Treefrog poison dart frog White’s African. Treefrog Dwarf Frog Horned Toad Fire-bellied Toad

Amphibians’ Defenses • Hiding - best defense is to remain undetected by blending in or by hiding under rocks, logs, or underground • Fleeing • Some frogs and toads emit a fluid that creates a burning sensation in the mouths of some predators, and can even be poisonous to humans

Where have all the frogs gone? Global Population Decline • • • a significant concern during the past decade frog declines widespread and well-documented (Puerto Rico, Ecuador, Venezuela, Brazil, U. S. Rocky Mountains, Cascade Mountain Range in Washington, Oregon, and California) possible causes include habitat destruction, increased UV radiation, acid rain, pollution and introduction of non-native species

Amphibian Malformations • 1995 – large number found in a pond in Minnesota • Significant and widespread similar reports over the last 10 years • 46 of Wisconsin‘s 72 counties have reported

Malformed Frogs & Toads

Dr. David Hoppe, University of Minnesota-Morris

Why Should We Care? • Play a very important role in the Earth’s ecosystem. – Major predators of insects – As high quality food/prey for birds, mammals, fish and reptiles

Why Should We Care? • Indicator of local environment – because they can absorb both oxygen and water through their skin, amphibians are particularly vulnerable to pollutants in the air or water and suffer from pollution even when they don't eat or drink it through their mouths.

Why Should We Care? • Direct benefit to mankind: – Many have skin secretions that can be used for pharmaceutical purposes, including cancer fighting drugs and drugs used to prevent heart attacks. • For their aesthetic “beauty”