1. 19.3 Evolution of Life I. __________ first vertebrates
A. Small __________ fishes 1st to appear
1. ex – __________ & ______________
B. _________ evolve
1. allow fish to _______ & _________ food instead of ____________ up
2. earliest kinds had __________, ____________ bodies
a. replace by __________, ________ bodies – _________ & bony fishes

2. C. ____________
1. Very efficient _____________
2. Skeletons not ________ but flexible
_____________
a. makes them __________ & more __________
3. ____________ of species evolved about _______ species survive today
D. _________ fishes
1. Replaced _________ as dominate species in _________
2. Evolved ______ filled bladder called
_______ ___________
a. enables fish to change ________ with little effort

3. II. ____________ onto land
A. Structural _______________
1. ___________
a. could absorb oxygen through skin, lungs are far more _____________
2. ___________
a. evolved from the ________ in fishes fins
B. Amphibians were very successful group
1. they have survived _________ million yrs outlasting the ____________
C. Not ___________ for land living
1. must return to water to ____________ and _______________ skin

4. III. ______________
A. Two key adaptations
1. ___________ skin – they would _____________ away from water
2. ___________ egg – can lay eggs on _______ land
B. For _____ million yrs there was _________ reptiles better suited to survive
C. ______________ Drift
1. movement of Earth’s land masses to ____________ positions

5. IV. __________ & ________________
A. After last extinction ____ mya any reptile bigger than _____ went extinct
B. The climate ____________ and was no longer ________
1. ________ & ___________ dominate landscape
C. Humans are the _____ species to do major ___________ to the Earth
1. Earth’s ______ lies in our hands