Answer to Question 1Because animals evolved in a moist environment, they had to adapt to the drying effects of the
atmosphere, so they had to develop an outer skin covering for protection. They also had to develop a
means to extract oxygen from the atmosphere rather than from water. Because animals need mobility
to find food, they also had to develop a means of locomotion, and a skeletal structure for support
against gravity. Finally, their reproductive system had to combat the problems of desiccation of
unprotected eggs
Answer to Question 2The most primitive vertebrates were the jawless fish, the ostracoderms. They had poorly developed
fins, an external covering of body armor, and were extinct by the end of the Devonian. Jawless fish
could only feed on detritus, but jawed fish, the acanthodians and placoderms, could chew food and
become active predators. Acanthodians appeared in the Lower Silurian with large spines, scales
covering much of the body, and reduced body armor. Placoderms evolved during the Late Silurian and
had considerable variety.
Land Plant Reproductive Terms
Comparing the extracellular environments of plants and animals
Animals and their offspring
Observed global land and ocean surface temperature anomalies since 1850
State the transformations on the function f(x)= 4sin(x-pi)-2 and then graph two cycles below.
Plot of Land (Modified Offset Method)