1. Chapter 3
Section 3

2. 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

3. 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

4. Amphibians

5. 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

6. Circulation

7. 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

8. Circulation

9. Circulation

10. 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

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

12. Amphibians

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

14. 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

15. Metamorphosis

16. Metamorphosis

17. 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

18. Moving on Land

19. Moving on Land

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

21. 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

22. Frog vs. Toad

23. 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

24. 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

25. Salamanders

26. 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