Do now activity What is speciation? Give an example of behavioral reproductive isolation. Explain. Give an example of geographic reproductive isolation. Explain. Give an example of temporal reproductive isolation. Explain.

Section 7-3: Gene frequency Essential Question: How do environmental factors impact gene (relative) frequency? Learning Target Justify why an advantageous trait will increase in proportion from one generation to another when provided statistical evidence. Use data to explain how change in gene frequency caused by natural selection is related to environmental factors such as seasonal temperature, climate change, acidity, light, geographic barriers, & evolution of other organisms. Section 7-3: Gene frequency

announcements Biology Tutoring this week: Lunch B (Tuesday & Thursday) 7:00AM (Monday – Friday) After school Biology Tutoring: Tuesday Section 6 Quiz Retakes are available until 2/17/17.

announcements Available Extra Credit: Tissue Box = 2 Points Starburst Original Jellybeans = 5 Points Stauffer’s Original Animal Crackers = 10 Points

Don’t forget to chunk your notes!

____ _____ is the number of times an allele occurs in a gene pool. overview ____ _____ is the number of times an allele occurs in a gene pool. Gene/Relative Frequency Evolution (genetic terms): any change in the relative frequency of alleles in a population

overview Relative (gene) frequency is the number of times an allele occurs in a gene pool. Gene/Relative Frequency Evolution (genetic terms): any change in the relative frequency of alleles in a population

overview Genetic drift is a random change in relative frequency because of chance.

In small populations, there can be more or less of an allele just by chance. Examples: Natural disasters Alleles passed on are random overview Remember, the smaller the group the less likely it will reflect the laws of probability Ex: coin toss

In small populations, there can be more or less of an allele just by chance. Examples: Natural disasters Alleles passed on are random overview Remember, the smaller the group the less likely it will reflect the laws of probability Ex: coin toss

In small populations, there can be more or less of an allele just by chance. Examples: Natural disasters Alleles passed on are random overview Remember, the smaller the group the less likely it will reflect the laws of probability Ex: coin toss

Natural selection ICE AGE Directional Selection can be caused when nature is against one end of variation. ICE AGE

Natural selection DROUGHT Stabilizing Selection can be caused when nature is against both ends of variation. DROUGHT

Disruptive Selection can be caused when nature is against the most common variation. Natural selection FUR COAT INDUSTRY

Founder effect Founder effect is when relative frequencies change because a small group of the population moves away. cyclins

Founder effect Founder effect is when relative frequencies change because a small group of the population moves away. cyclins

Founder effect If, by chance, an individual with a specific allele can reproduce a lot, then there will be more of the allele in the population. cyclins

Sample of Original Population examples Sample of Original Population

Sample of Original Population examples Founding Population A Sample of Original Population Founding Population B

Sample of Original Population examples Founding Population A Sample of Original Population Descendants Founding Population B

Do now activity How is the picture an example of genetic drift? How is the picture an example of Founders Effect? Genetic drift because the relative frequency changed from mutation at 4.5% to 20% to 41% (Total is 22) because of earthquake/death/etc. Founders because Small group moved away so relative frequency of original population went from 4.5% to 0% mutation