1. Place these events in history of life on earth in the order that they occurred..
g. origin of prokaryotes
d. origin of eukaryotes
f. origin of multicellular organisms
c. diversification of animals (Cambrian explosion)
b. colonization of land by plants and fungi
a. colonization of land by animals.
e. origin of humans
Place the following steps in the origin of life in the order that they are hypothesized to have occurred.
d. abiotic synthesis of organic monomers
c. abiotic joining of organic monomers into polymers
a. integration of abiotically produced molecules into membrane-enclosed pre-cells
b. origin of the first molecules capable of self-replication
e. natural selection among pre-cells
DNA replication relies on the enzyme DNA polymerase. Why does this suggest that the earliest genes were made from RNA?
DNA polymerase is a protein, which must be transcribed from a gene. But a DNA gene requires DNA polymerase to be replicated. This creates a paradox about which came first - DNA or protein. But RNA can act as both an information storage molecule and an enzyme, suggesting that a dual-role RNA may have preceded both DNA and proteins.
