2. Evolution is non-random changes in gene and allele frequencies within a population or species. Random changes can be caused by: 1) 2) 3)

3.  Change to allele _______________as a result of chance is called genetic drift. In a small populations, this change plays a _______________role for altering allele frequencies. Spinner

4.  Bottleneck Effect – When a drastic _____________in population occurs (often temporary) it usually results in significant genetic drift.

5.  When a few individuals from a _________ population leave to establish a ________ population, the resulting genetic drift is a ______________________. With self-pollinating plants  entire population can be established by one seed.

6.  When alleles ________ from one population to another population, they _________ the alleles frequency of both. This movement of allele is called a gene flow.  Unlike genetic drift, gene flow tends to ____________ differences between populations.

7.  Mutations are the result of _____________ changes in DNA sequence or chromosome breakage and rejoining.  They are the only source of __________________ genetic material and new alleles  Only the mutation that occurs in ________________ can pass on the new phenotype.

8. 1. 2. 3.

9.  Mostly ___________and has no immediate effect on an individual’s fitness. _____________ refers to the lifetime reproductive success of an individual.  Usually occurs when a cell loses the ability to ____________a properly functioning protein or when major chromosomal changes badly affect meiosis and mitosis, and it reduces an individual’s fitness.

10.  Occurs when cell gains the ability to produce a ______ or ______________ protein, which gives an individual a selective advantage of, increased reproductive success.