Bellwork: 1/7/16 Explain why this does NOT show evolution You will also need a pen/pencil and your journal/paper today Have your homework out for me to collect

Science Fact of the Day: There's enough gold in the Earth's crust to cover the entire land surface knee-deep.

Essential Question: How does evolution happen? (you may continue your notes from Tuesday)

I. Mechanisms of Evolution

A gene pool is the total number of genes of every individual in an interbreeding population.

Evolution can be defined as a change in the gene pool over time.

Genetic Drift is a random change in the frequency of alleles in a population due to random sampling.

There are 5 factors that can affect the frequency of a gene in the gene pool. 1.Genetic Mutation 2.Non-random mating 3.Natural Selection 4.Small Population 5.Gene Flow

4. Small Population 1.Bottleneck effect- when a large portion of a population dies (REDUCES gene pool). 2.Founder effect- when a few individuals from a group leave and start another population in a different place (REDUCES gene pool)

A decrease in the size of a gene pool increases the speed of evolution and visa versa.

5. Gene Flow 1. Gene flow is the movement of genes into or out of a population. a.Emigration- when individuals leave (EXIT) a population decreasing the size of the gene pool. b.Immigration- when individuals from a different population enter (INTO) a new population and begin breeding. This increases the size of the gene pool.

Speciation: creation of 2 different species from 1 original species Macroevolution: total of many changes that transform organisms over a long period of time. Microevolution: small change over a period of time Changes in the frequency of a gene in a gene pool leads to

Scenarios

1.Amish people are required by their religion to only marry and have children with other Amish people.

2. The DNA sequence in a bird is changed from ATT CCG TTG to TTA CCG TTG which changes the beak shape from long and thin to short and fat.

3.Peppered moths are eaten by birds. The moth color varies from light to dark. Light colored moths can blend in with a nearby species of tree. In the 1800s factories released large amounts of soot, which changed the tree color, so the birds were able to more easily find the lighter moths instead of the darker moths.

4. Northern elephant seals were hunted almost to extinction by people in the 1890s. The remaining population has reduced genetic variation.

5. A lioness joins a new pride and has cubs with the male lion.

6. A small group of birds flies from the mainland to an island and starts a new colony. (The birds never return to the mainland.)

On a separate sheet of paper… answer the questions around the room. Please, write the number of the question and your answer.

Mix-Freeze-Group I am going to survive! Because I have the best genes for my environment. I am HUGELY affected by genetic drift. I am VERY picky. I will only choose you, because your traits are most attractive to me. I am a mistake in the DNA sequence Natural Selection Small Population Genetic Mutation Non-Random Mating

Changes in the frequency of a gene in the gene pool initially leads to microevolution. Microevolution refers to a small change in a population over a short amount of time. Many small changes eventually lead to macroevolution. Macroevolution refers to the sum total of many changes that transform organisms over a long period of time. Macroevolution leads to speciation or the creation of a new species. When an evolving population can no longer interbreed with the original population, a new species is formed.