Bell-Ringer 2/13: Phones away! Turn in Critical Reading for 100 bonus You have 10 mins to finish and turn in the Types of Selection Worksheets from Friday!

Mechanisms of Evolution - Gene Flow & Genetic Drift https://www.youtube.com/watch?v=11iYk0Yrx3g

2/13-Phones Away People. Have your stamp sheet out along with #12-Rock Pocket mouse #13-Natural selection Evidence of Evolution Quiz Re-Takes today-Thurs.

Gene Flow Activity You need 3 sets of 10 fish (3 colors total) Divide students up into 3 groups (populations) Give each group of students the same color fish A “dam” is placed around one group – they can’t move Let all students not in the dammed population “swim” for 10 seconds. They can only go from one population to the next. Once they stop ask – how is your new population different from the other? How does the population trapped by the dam differ? Remove the dam and allow the populations to mix again for 10 seconds How do the groups differ now? These fish can also be used to model the bottleneck effect and the founder effect

Today’s objective We will: explain how gene flow and genetic drift affect the gene pool of a population. I can: compare and contrast between genetic drift and gene flow.

What is a Gene Pool? Gene pool: All of the genes in a population

What is Allele Frequencies? Allelic Frequency: The frequency of a specific allele Ex: A or a

Q: What are some factors that could cause a population’s gene to change? How can we change the gene pool of a population?

With your partner, describe what is happening to the population in the picture. Population A Population B

Predict what would happen to population A over time? Population A Population B

Gene Flow “Go with the Flow” Definition: When alleles travel from one population to another population of the same species. Also known as Migration. *This is another way to introduce new alleles in to a population.

Gene Flow

Gene Flow

Examples of Gene Flow 1. Brown beetles enter into a community consisting solely of green beetles, creating offspring with greater color diversity. 2. A population of flowers on one side of a river transports pollen to the flowers on the other side of the river, producing offspring.

**Gene Flow Increases Genetic Variation!

With your partner, describe what is happening in the picture.

Is this random or non random?

Predict what would happen to the gene pool of the population over time.

Genetic Drift “Drift is RanDom” Definition: When the allele frequencies of a population is changed due to randomness or chance. Genetic Drift reduces genetic diversity

Two types of Genetic Drift: Bottle Neck effect and Founders effect https://www.youtube.com/watch?v=Q6JEA2olNts

Bottle Neck Effect Caused by: when an environmental event effects a large population and only a few individuals survive.

Example of Bottle Neck Effect Northern Elephant seals- reduced population and generic variation due to hunting An example of a bottleneck: Northern elephant seals have reduced genetic variation probably because of a population bottleneck humans inflicted on them in the 1890s. Hunting reduced their population size to as few as 20 individuals at the end of the 19th century. Their population has since rebounded to over 30,000—but their genes still carry the marks of this bottleneck: they have much less genetic variation than a population of southern elephant seals that was not so intensely hunted.

Founders Effect Caused by: when only a few individuals start a new colony

Examples of Founders Effect Example: Polydactyl (6 fingers) in Amish communities For example, the Afrikaner population of Dutch settlers in South Africa is descended mainly from a few colonists. Today, the Afrikaner population has an unusually high frequency of the gene that causes Huntington’s disease, because those original Dutch colonists just happened to carry that gene with unusually high frequency. This effect is easy to recognize in genetic diseases, but of course, the frequencies of all sorts of genes are affected by founder events. Examples of this showing up in human populations is polydactyl among Amish communities or the Blue people of Kentucky. Unlike bottlenecks, which persist as long as the effective population size remains low, a founder effect is an instant event. 

Examples of Founders Effect Examples: Blue people of Kentucky http://www.travelchannel.com/s hows/mysteries-at-the- museum/video/blue-people- roaming-the-hills

2/13-Phones Away People. Evolution Crossword: Galapagos Stamp # 14-crossword puzzle

Its your turn to practice! Read each scenario and Identify the forces of evolution