In this chapter you will explore the beginnings of life on Earth. You will learn about early experiments that tested the theory of spontaneous generation. You will also examine our current understanding of the evolution of multicellularity, photosynthesis, aerobic metabolism, and sexual reproduction.

In this chapter, you will: define spontaneous generation describe conditions on ancient Earth discuss various hypotheses on the evolution of cells relate oxygen production in photosynthesis to the evolution of aerobic metabolism