The origin and evolution of eukaryotes

Question 1

What evidence proves that there is a consensus that eukaryotes descended from prokaryotes

Answer 1

Evidence includes the observation that both eukaryotes and prokaryotes use the same genetic code and share many metabolic pathways

Question 2

When did eukaryotes originate

Answer 2

Prokaryotes had the earth to themselves for many years since the origin of life (dated to 3.5 billion years ago). The first eukaryotic fossil is approximately 2 billion years old. The discovery in datable oil deposits of biochemicals produced only by eukaryotes suggests an earlier origin, almost 3 billion years ago.

Question 3

Provide a brief overview of the evolution of eukaryotes

Answer 3

The first eukaryotes began as unicellular organisms. Multicellularity began with the formation of colonies, followed by cell specialization, perhaps first by simple symbiosis. Developmental programmes allowed specialization within clonal clusters. There followed exploration of a great variety of body plans, based on a variety of tissue types. Major landmarks that we know about, in the development of higher organisms, include the division between animals and plants. Some animals adopted body structures with bilateral symmetry, some of these became vertebrates and eventually, some became humans.