Chapter 3 Section 3

Amphibians Amphibian: Amphibians spend their adulthood on land Ectothermic vertebrate that spends its early life in water Amphibians spend their adulthood on land They return to water to reproduce

Amphibians Reproduction: They lay eggs in the water Eggs hatch into larvae that swim Have gills to obtain oxygen Undergo metamorphosis As adults they have lungs Obtain oxygen and get rid of carbon dioxide through their thin, moist skin

Amphibians http://static.ddmcdn.com/gif/frog-life-cycle.gif

Circulation Tadpole circulatory system Adult circulatory system Single loop while they have gills Like fish Adult circulatory system Double loop when they have lungs 1st loop: Blood flows from heart to lungs and skin to pick up oxygen 2nd loop: Blood flows to the rest of the body to deliver oxygen-rich blood

Circulation http://universe-review.ca/I10-82-circulatory.jpg

Circulation Chambers of the heart: Atria: two upper chambers of the heart that receive blood 1 receives oxygen-rich blood from the lungs The other receives oxygen-poor blood from the body Ventricle: lower chamber of the heart that pumps blood out to the lungs and the body Oxygen-rich and oxygen-poor blood mix here

Circulation http://www.coolcompanions.com.au/wp-content/uploads/2010/06/The-three-chambered-frog-heart-mixes.jpg

Circulation http://www.biologycorner.com/resources/frog-heart.gif

Amphibians Reproduction: Male frogs or “peepers” using a call to attract mates Most frogs and toads use external reproduction Female releases eggs that are fertilized by sperm Salamanders use internal reproduction Eggs are fertilized before they are laid

Amphibians Reproduction: Eggs are coated with a clear jelly to remain moist Tiny embryo develops Few days later larvae wriggle out of the jelly

Amphibians

Amphibians Care: Most young are on their own right away Exceptions: South American River Toad Male presses the eggs into the female’s back

Metamorphosis Metamorphosis Hind legs appear Changes in the skeleton, circulatory system, and digestive system Front legs appear Loses its gills and starts to breathe with lungs Frogs and toad adults look different than larvae Salamander larvae resemble the adult

Metamorphosis http://dj003.k12.sd.us/SCHOOL%20NOTES/029%20Life%20cycle%20of%20a%20frog.jpg

Metamorphosis

Moving on Land Adaptations to life on land: Strong skeleton Muscular limbs 1st vertebrates to have legs Eyes Transparent membrane to keep them from drying out Eyelids

Moving on Land

Moving on Land

Frogs and Toads Adaptations Powerful hind-leg muscles Skeleton to absorb shock Webbed feet and long toes – Bullfrogs Adhesive suckers – Tree frogs

Frogs and Toads Distinguish a frog from a toad: Frog skin is smooth and moist Toad skin is dry and bumpy Toads have lumps behind their eyes Contain a poisonous liquid when attacked

Frog vs. Toad

Frogs and Toads What do they eat? Tadpoles Adult Frogs and Toads Herbivore Adult Frogs and Toads Predators that eat insects or small animals Camouflaged to blend into their environment Brownish green to blend into ponds

Salamanders Keep their tails as adults Legs are not adapted for jumping Some live in water their whole life while other live on land Some do not have lungs They obtain oxygen through their moist skin Do not return to water to reproduce Lay their eggs on land in moist places

Salamanders

Amphibians in Danger In danger due to habitat destruction Swamps are filled in Forest is cut Moist area becomes dry Environmental poisons Insecticides and other chemicals pollute water