evolution: part 1 the driver of the diversity and unity of life

Evolution: Part 1The driver of the diversity and unity of life

Lamarck vs. DarwinTheory of Use and Disuse• Acquired

Transmission• Increasing

Complexity• No Extinction• Heritability• Selective

Pressure

Lamarck vs. DarwinTheory of Use and Disuse• Acquired

Transmission• Increasing

Complexity• No Extinction• Heritability• Selective

Pressure

Theory of Natural Selection• Variations• Extinction (or

Species Creation)

• Heritability• Selective

Pressure

_______________ do not evolve,

________________ evolve.

Individuals

Populations

Evidence for EvolutionScientific observation and documentation

HomologyFossil RecordBiogeography

Homology

Homologous Structures

Analogous Structures

Homologous• Anatomical similarity, possibly

different function• Occurs because of evolution and

inheritance

Analogous• Little to no anatomical similarity,

similar function of structures• Occurs because of convergent

evolution

Vestigial Structures

Vestigial Structures

•Structures that were once useful to an ancestor but have lost their usefulness and have decreased in size over many generations

Biogeography https://youtu.be/cC8k2Sb1oQ8?t=2m53s

Can evolution occur if a population is operating under the Hardy-Weinberg principle?

Hardy-Weinberg Principle

The frequency of alleles and genotypes in a population will remain constant from generation to generation.

5 Conditions for Hardy-Weinberg

1. No mutations

2. Random mating

3. No natural selection

4. Extremely large population size

5. No gene flow

Evolution: Part 2Hardy Weinberg continued, changes in allele frequencies

Hardy Weinberg warm-up

A very large population of randomly-mating laboratory mice contains 35% white mice. White coloring is caused by the double recessive genotype, "aa". Calculate allelic and genotypic frequencies for this population.

Changes in Allelic Frequencies

Genetic Drift

Natural Selection

Gene Flow

Genetic Drift Activity

http://www.biology.arizona.edu/evolution/act/drift/frame.html

Why is having a large population beneficial in terms of allele fixation?

Why is allele fixation usually detrimental evolutionarily?

Changes in Allelic Frequencies

Genetic Drift• Founder effect• Bottleneck effect

Natural Selection

Gene Flow

Genetic Drift – Founder EffectSudden isolation of a small population

from a larger population in which the smaller population establishes a new population.

Would the smaller population look the same as the larger population 500 generations down the line?

Genetic Drift – Bottleneck EffectA severe drop in population size

due to a sudden change in the environment

Does natural selection play a role in this?

Changes in Allelic Frequencies

Genetic Drift

Natural Selection

Gene Flow

Natural Selection

https://www.youtube.com/watch?v=sjeSEngKGrg&feature=youtu.be

Changes in Allelic Frequencies

Genetic Drift

Natural Selection

Gene Flow

Directional Stabilizing

Disruptive

What type of selection occurred in the pocket mice?