Amphibians Flashcards
What is an amphibian?
A creature with two lifestyles, one on land and one of water
What is a tetrapods?
A creature with four limbs
From what organism did amphibians evolve from?
Evolved from lobe finned fish, fish that possessed both lungs and gills and had four fleshy find supported by bones in hand like structure
What are lobe finned fish?
Lungfish, ability to breathe in and out of water, robust fleshy find that served as legs similar to bone structure disadvantage was no strengthening girdle connecting bones at extremities to rest of skeleton. Present developed from swimbladders. Could move from one water source to another
How do we know about lobe finned fish?
Fossil remains found in Devonian strata, live specimens can be found today, coelacanths, am fish that have remained virtually unchanged for millions of years
What similarities are seen between lobe-finned fish and early amphibians?
4 fins and four limbs Limbs in same position Lacked nails and claws Skull morphology similar, amphibians became smaller in size to become neck Teeth very complex Tail fin present Bony scales in their skin
How were early amphibians adapted to life on land?
Girdle connecting limbs to skeleton More robust skeleton for support on land Eyelids formed to keep eyes moist Double loop circulatory system Tongue formed in its mouth Ears adapted to detect sound
Why did early amphibians have to remain close to a water source?
Used skin for gas exchange so had to keep it moist
Lay eggs in water do didn’t dry out
Young hatch into aquatic larvae with gills, undergo metamorphosis to developing Adult
What allowed for evaluation of dinosaurs, eggs and mammals?
Amniotic eggs
