selection and evolution

Selection and Evolution

Jory Weintraub, Ph.D.National Evolutionary Synthesis Center (NESCent)

Where Do I Work?National Evolutionary Synthesis

Center (NESCent)

What is Evolution?

CHANGE OVER TIME…

It explains the diversity of life on Earth!

Evolution = Change Over Time

U.S. Department of Energy Human Genome Program, http://www.ornl.gov/hgmis

Mutations Affect Genes, Proteins, Traits

Genotype – The genetic makeup of an individual(i.e., the genes it has)

Phenotype – The physical manifestation of the genotype(i.e., what it looks like)

Animal Distributions

Closely related organisms found in geographical proximity

Evidence for Evolution

Homology

The spatial and developmental equivalence of traits that may look quite different

Evidence for Evolution

Vestigial Features

Speaks to imperfect “design”. Best explained by the persistence of shared

traits.

Evidence for Evolution

Individuals in a population that are better adapted for a

particular environment, survive and pass their traits on to their offspring

H.E. Hoekstra

How Does Evolution Work?Through a process called “Natural Selection”

Natural SelectionThe Pocket Mouse Example

Natural SelectionThe Pocket Mouse Example

What can we conclude?

The mice that blend in have an advantage over those that stand out.

They survive and reproduce.

What other types of selection are there besides

Natural Selection?

Sexual Selection (Sexual Dimorphism)

Sexual SelectionThe Birds of Paradise Example

Sexual SelectionThe Birds of Paradise Example

What can we conclude?

The birds that stand out have an advantage over those that blend in.

They have more chances to reproduce.

Natural Selection suggests it is

better to blend in…

Sexual Selection suggests it is

better to stand out…

Can you come up with a theory(or theories) to explain this?!?

Are there any other types of selection?

An Example of Evolution in Action…

BM vonHoldt et al. Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication Nature 000, 1-5 (2010) doi:10.1038/nature08837

A: It is artificial selection

Q: Is this natural selection?

Conclusion: Several forms of selection lead to

change over time

QUESTIONS???

Jory Weintraubjory@unc.edu