Chapter 6 Lec1

Question 1

Give the evidence that there is consensus that eukaryotes are descended from prokaryotes.

Answer 1

The evidence is that prokaryotes and eukaryotes use the same genetic code; also share many metabolic pathways.

Question 2

When did eukaryotes originate?

Answer 2

The 1st eukaryotic fossil is ~2 BYA; however, datable oil deposits of biochemical produced only by eukaryotes suggest an earlier origin, almost 3 BYA (thus,a billion years earlier than thought)
And prokaryotes had the world to themselves for many years before then.

Question 3

Discuss the evolution of eukaryote.

Answer 3

1) 1st eukaryotes began as unicellular organisms;then multicellular which began with formation of colonies,followed by cell specialization (via symbiosis).
2) developmental programmes allowed specialization within clonal clusters.
3) then exploration of various body plans based on a variety of tissue types.
4) major landmarks include evolution of animals and plants; some adopted body structures with bilateral symmetry and some became vertebrates.