3.3Notes - MACCRAY Schools
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Transcript 3.3Notes - MACCRAY Schools
Chapter 3
Section 3
Amphibians
Amphibian:
– 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
– 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-threechambered-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
1. Hind legs appear
2. Changes in the skeleton, circulatory system, and
digestive system
3. Front legs appear
4. 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%2
0cycle%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
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