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