This topic contains a solution. Click here to go to the answer

Author Question: Briefly state the problems that animals faced in their adaptation to land. What will be an ideal ... (Read 71 times)

viki

  • Hero Member
  • *****
  • Posts: 525
Briefly state the problems that animals faced in their adaptation to land. What will be an ideal response?

Question 2

Describe the evolution of fish in the Paleozoic. What will be an ideal response?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

nixon_s

  • Sr. Member
  • ****
  • Posts: 359
Answer to Question 1

Because 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 2

The 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.






 

Did you know?

Increased intake of vitamin D has been shown to reduce fractures up to 25% in older people.

Did you know?

There are over 65,000 known species of protozoa. About 10,000 species are parasitic.

Did you know?

Eating carrots will improve your eyesight. Carrots are high in vitamin A (retinol), which is essential for good vision. It can also be found in milk, cheese, egg yolks, and liver.

Did you know?

The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.

Did you know?

In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.

For a complete list of videos, visit our video library