Fundamental Concepts for

Essential Principle 4: The ocean makes Earth habitable.

4a. Most of the oxygen in the atmosphere originally came from the activities of photosynthetic organisms in the ocean.

K-12 Scope and Sequence: Grade band 3-5 mentions concepts; Grade bands 6-8 and 9-12 address concepts in depth.

4b. The first life is thought to have started in the ocean. The earliest evidence of life is found in the ocean.

K-12 Scope and Sequence: Grade band 3-5 mentions concepts; Grade bands 6-8 and 9-12 address concepts in depth.