1. More Natural Selection Info
Describe Natural Selection including the 3 things needed for it to occur
Define adaptation
List and describe five examples of natural and artificial selection

2. Natural Selection 1. There is competition for limited resources
2. There is natural variation (behavior, traits)
3. The variation is inherited
The outcome of variation in heritable traits that affect survival and reproduction

3. Adaptation The consequence of natural selection is adaptation
Adaptation: some heritable aspect of form, function, behavior or development that improves the odds for surviving or reproducing in a given environment.

4. Artificial Selection

5. Artificial Selection

6. Natural Selection http://www.museums.org.za/bio/insects/cockroaches/

7. Natural Selection
Staphylococcus aureus: antibiotic resistance

8. Population Information
Define population
Describe the basis and source of heritable variation within a population
If there are heritable variations within a population, when does evolution not occur?

9. How would you define POPULATION?
all organisms that constitute a specific group (species) in a specific habitat/environment

10. Review of Genetics Cells are the basic unit of life Cells have DNA
DNA contains genes
Genes code for proteins, usually enzymes
Genes that differ slightly are called alleles
Different alleles make different forms of the same enzyme
These enzymes determine an organisms phenotype
Alleles can be inherited

11. Population Genetics
Gene pool: all the alleles of all the genes in all the individuals in a population
Each organism will have a unique combination of alleles and, therefore, a unique phenotype
Unique combination of alleles
Mutation
Crossing-over
Independent assortment
Fertilization
Change in chromosome number or structure

12. Population Genetics
Allele frequency: relative proportion of one allele for one gene
Evolution: change in the allele frequency within a population

13. How does Evolution Occur?
Describe how evolution can occur
Mutation
No gene flow
Small population size
Non-random mating
Natural selection
Disruptive
Directional
Stabilizing

14. Violation of equilibrium: mutation
Mutations are rare (1/100,000 gametes)
Mutations can be:
Helpful
Depends on
environment
Neutral
Harmful
Lethal mutation

15. Gene Flow
Individuals, and their alleles, move into and out of populations
The physical flow counters the effects of:
mutation
natural selection
genetic drift

16. Small Population Size Hypothesis: how often will you get tails?
Flip a coin ten times:
# heads
# tails
Everyone flip a coin ten times:
Discuss the difference between 10 and 200 events: sampling error

17. Small Population
Random events can have drastic effects on the allele frequencies in a small population: Genetic Drift
Two examples:
Founder effect
Bottleneck

18. Founder Effect phenotypes of original population
A seabird carries a few seeds, stuck to its feathers, from the mainland to a remote oceanic island.
phenotype of island population

19. Bottleneck Effect: Elephant seal
Reduction of a population’s gene pool produced when a few members survive the widespread elimination of a species.
Figure: 14-03b
Title:
Population bottlenecks reduce variation.
Caption:
(b) The northern elephant seal passed through a population bottleneck in the recent past, resulting in an almost total loss of genetic diversity.
Año Nuevo State Park

20. Non-random mating
Do humans mate randomly?
How do people pick a mate?

21. Non-random mating: 3 types
Assortive – shifts genotype frequency
Organisms choose a mate with the same genotype as themselves.
Organisms choose a mate with a different genotype from themselves.
Self-fertilization – shifts genotype frequency
Organism mates with itself
Sexual selection –shifts allele frequency
Some genotypes mate more successfully than others

22. Assortive Mating

23. Self-fertilization

24. Sexual selection

25. Natural Selection
Evolution due to natural selection results from unequal reproduction of various alleles
Natural selection acts on phenotypes but affects genotypes
Adaptations help an individual survive and reproduce

26. Agents of Natural Selection
Abiotic factors
Climate
Geology
Other non-living factors
Biotic factors
Competition
Food, Shelter, Mating
Interspecies Interactions
Predation
Sexual Selection

27. 3 Modes of Natural Selection:
Range of values at time 1
Number of individuals
3 Modes of Natural Selection:
Directional Selection
Range of values at time 2
Number of individuals
Range of values at time 3
Number of individuals

28. 3 Modes of Natural Selection:
Number of individuals
3 Modes of Natural Selection:
Stabilizing Selection
Range of values at time 1
Range of values at time 2
Number of individuals
Range of values at time 3
Number of individuals

29. 3 Modes of Natural Selection:
Disruptive Selection
Number of individuals
Range of values at time 1
Range of values at time 2
Number of individuals
Range of values at time 3
Number of individuals