Paleontology, genetics, and molecular evidence all support evolution through fossils, DNA and protein comparisons. Genetic variation within populations increases the chances of survival and comes from mutation, recombination and hybridization. Natural selection can act on populations in three ways - directional selection favors one phenotype extreme, stabilizing selection favors intermediate phenotypes, and disruptive selection favors both extremes.

1. KEY CONCEPT New technology is furthering our understanding of evolution.

2. Fossils provide a record of evolution. Paleontology is the study of fossils or extinct organisms.

3. Paleontology provides evidence to support evolution.

4. Molecular and genetic evidence support fossil and anatomical evidence. Two closely-related organisms will have similar DNA sequences. What would you expect to find the differences code for?

5. Pseudogenes are sequences providing evidence of evolution.no longer function

6. carried along with functional DNA

7. can be clues to a common ancestorHox genes indicate a very distant common ancestor.control the development of specific structures

8. found in many organisms

9. Protein comparisons, or molecular fingerprinting reveals similarities among cell types of different organisms.Evolution unites all fields of biology. Scientists from many fields contribute to the understanding of evolution.

10. The basic principles of evolution are used in many scientific fields. Some for good purposes and some for less ethical – give an example of each.KEY CONCEPT A population shares a common gene pool.

11. Remember me?GenotypicPhenotypic

12. Genetic variation in a population increases the chance that some individuals will survive.Genetic variation leads to phenotypic variation. Why?Phenotypic variation is necessary for natural selection. Why?Genetic variation is stored in a population’s gene pool.made up of all alleles in a populationallele combinations form when organisms have offspring – How?

13. Allele frequencies measure genetic variation.measures how common an allele is in population

14. can be calculated for each allele in gene poolGenetic variation comes from several sources.Mutation is a random change in the DNA of a gene. can form new allele

15. can be passed on to offspring if in reproductive cells – why not from body cells?

16. Recombination forms new combinations of alleles.

17. usually occurs during meiosis

18. parents’ alleles arranged in new ways in gametesGenetic variation comes from several sources.Hybridization is the crossing of two different species.occurs when individuals can’t find mate of own speciestopic of current scientific research

19. KEY CONCEPT Populations, not individuals, evolve.

20. Natural selection acts on distributions of traits. A normal distribution graphs as a bell-shaped curve. highest frequency near mean value

21. frequencies decrease toward each extreme value

22. Traits not undergoing natural selection have a normal distribution.

23. Give an example of a trait that could have a normal distribution.Natural selection can change the distribution of a trait in one of three ways. Microevolution is evolution within a population.observable change in the allele frequencies can result from natural selection

24. Natural selection can take one of three paths. Directional selection favors phenotypes at one extreme. What’s happening in this graph?Natural selection can take one of three paths. Stabilizing selection favors the intermediate phenotype.