Closure of the AV valves produces the first heart sound (S1).

TLS Online TPP Program

#Id: 2152

#Unit 9. Diversity of Life Forms

Use different parts of the genome to estimate different parts of a phylogeny.

TLS Online TPP Program

#Id: 2153

#Unit 9. Diversity of Life Forms

Rates of molecular evolution vary among DNA sites, among genes, and among lineages of organisms.

TLS Online TPP Program

#Id: 2154

#Unit 9. Diversity of Life Forms

Second positions most slowly evolve.

TLS Online TPP Program

#Id: 2155

#Unit 9. Diversity of Life Forms

Use more rapidly evolving parts of the genome to estimate phylogenies in the recent past. More slowly evolving parts for deeper evolutionary time.

TLS Online TPP Program

#Id: 2156

#Unit 9. Diversity of Life Forms

Radiation- Several species arise from a common ancestor over a short time

TLS Online TPP Program

#Id: 2157

#Unit 9. Diversity of Life Forms

Phylogenetic relationships among species in a radiation are difficult to determine for two related reasons.                                                                 

a. During the short time between two successive speciation events, few new mutations are fixed.                                                                               

b. Incomplete lineage sorting may occur during rapid diversification.