“The field of macroevolution embraces the excitement of seeking an understanding of the breadth of life” -Levinton

Taxonomic-based definition “Evolution above the species level” Between species evolution (as opposed to within species, which is microevolution)

Splitting vs. Budding S B Change in both descendants Change in one

Bottleneck Effect Extreme form of Genetic Drift. Entire population goes through this. X Z B B B

Founders Effect Extreme form of Genetic Drift X Z X Z B X Z

Founders Effect

What is Macroevolution? Macroevolutionary Questions: Big Question 1: How do we establish evolutionary relationships among taxa? Specific: Who are humans’ closest relatives? www.bushorchimp.com

Why are there still chimps? Science does not say we descended from modern chimps Does say humans and modern chimps descended from a common ancestor The common ancestor probably had some characteristics of both species.

Macroevolutionary Questions Big Question 2. What processes/factors regulate the rates of evolutionary change? Specific: Do mice evolve faster than elephants?

Macroevolutionary Questions: Big Question 3: What environmental changes regulated the timing of evolutionary radiations and extinctions? Specific: Why did dinosaurs become extinct?

Macroevolutionary Questions Big Question 4. Do extinctions affect the evolution of other groups? Specific: Did the Extinction of dinosaurs allow the radiation of Mammals?

Macroevolutionary Questions Big Question 5 – What ecological processes regulate diversity? Specific: Did ecology contribute to the “Cambrian explosion”?

Phylogenetic systematics Based on number of homologies between groups Greater number of homologous characters between species the closer the relationship Cladistic Analysis Clade: An ancestral species and all its descendants (shared homologous characters). Should be monophyletic.