What problems were associated with colonizing land during the evolution of vertebrates?

1) Animals needed to withstand the effects of gravity.

2) Animals needed to reduce desiccation (the loss of water).

3) Animals needed to have a mode of transportation.

4) Animals needed protection against UV rays.

5) Animals needed to reproduce without water.

6) Animals needed to breathe air.

7) Animals needed to adjust their senses to life out of water.