The fishes established the basic design and functionality of all vertebrates. So, starting with the fishes:
1. Explain what changes had to occur for the amphibians to move from total dependency on the water environment to their new habitat.
2. Amphibians were only partly successful, but what morphological and physiological adaptations worked for them? Why were they not totally successful? (not true terrestials - bone structure, types of skin, lungs.. )
3. The reptiles were the first true terrestials. What adaptations made terrestrial life truly possible for the reptiles and their descendants?
4. Discuss what characteristics reptiles, birds, and mammals share in common? Why do they share these characteristics? (stem reptile theory) How do they differ?

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[QUOTE=littlenloud06
1. Explain what changes had to occur for the amphibians to move from total dependency on the water environment to their new habitat.
2. Amphibians were only partly succesful, but what morphological and physiological adaptations worked for them? Why were they not totally successful? (not true terrestials - bone structure, types of skin, lungs..)
3. The reptiles were the first true terrestials. What adaptations made terrestrial life truly possible for the reptiles and their descendants?
4. Discuss what characteristics reptiles, birds, and mammals share in common? Why do they share these characteristics? (stem reptile theory) How do they differ?[/QUOTE]

1-3) Think about the diferrences between fish and amphibians. How do they help them live on land? Then think about the difference between amphibians and reptiles- why can a lizard live in a desert but a salamander can't?

4) Make a table of similarities and think about what the question is asking! The clue is in stem reptile theory.