The challenges to survival in the marine environment are different from those on land. The ways by which marine organisms meet these challenges are often unique. Their body functions are designed to work well in their environment. To become more aware of the problems and solutions of living in the sea, you can identify potential challenges to life and investigate the ways in which a particular species overcomes them.

One of the greatest challenges faced by organisms is the creation of offspring. Marine organisms have evolved a variety of ways to produce the next generation. Some marine organisms reproduce entirely asexually while others reproduce entirely sexually. Still others are capable of both asexual and sexual reproduction. This sometimes leads to a reproductive strategy that utilizes the advantages of both types of processes.

To master the competencies, you should be able to:

1. Describe how the marine environment is unique physically and chemically.
2. Relate the constancy of sea temperatures to the heat capacity of water.
3. Relate the buoyancy of an object in the ocean to its density relative to the density of seawater.
4. Associate the depth in the ocean with the amount of pressure exerted by the water and the amount of ambient light.
5. Explain the way in which the concentration of gasses and salts in a marine creature's body is like that of the surrounding seawater.
6. Compare and contrast asexual and sexual forms of reproduction.