You DO NOT need to write this Bellwork!

Two species of mice live in a field in the middle of East Texas. One mouse species is white with black spotting. The other is brown with white spotting.

After a year, the population of white mice has dramatically decreased, while the population of the brown mice has slightly increased.

Why would this be happening?

Bellwork: January 9Copy the questions and write your answers!

Mrs. PigglyWiggly is a carrier of the sex-linked hemophilia allele, and Mr. PigglyWiggly is normal, as far as blood chemistry goes. Use the letter “H” to represent the hemophilia allele.

1. What would be Mrs. PigglyWiggly’s genotype?

2. Draw a Punnet square that shows the theoretical genotypes among their children (cross Mr & Mrs).

3. What percent chance would their sons have hemophilia?

Science Fact of the Day:Mosquitoes like the scent of estrogen, hence, women

get bitten by mosquitoes more often than men do.

CO: I will analyze how evolution occurs in a population. I will

examine evidence for evolution.

LO: I will talk about evolution with the class. I will write notes about

evolution.

Let’s chat about our potato farms!

Evolution: What is it?

Evolution: change in heritable traits of a population across generations (over time).

Charles Darwin: contributed more to our understanding of evolution than anyone else.

• Darwin traveled, made observations and collected evidence that led him to propose his revolutionary process in a book called Origin of the Species.

Population size is limited by environmental resources

Fitness: the ability of an organism to survive and reproduce.

• Fitness is the result of adaptations.

Adaptation: any inherited characteristic that increases an organism’s chance of survival.

Successful adaptations: - enable organisms to become better suited to their

environment - increase an individual’s ability to survive and

reproduce.

Humans have thousands of adaptations: large brain, opposable thumbs, excellent sensory organs, light, strong skeleton, etc.

The Primary Mechanism of Evolution:

Natural Selection

Natural selection: the process by which individuals with characteristics that are not well suited to their environment either die or leave few offspring.

1. Also referred to as survival of the fittest.

2. It is not seen directly, but only observed as changes in a population over a long time.

Bunny Simulation

If only one species is considered the "fittest", why do we still have so many variations among species. Why do some birds have very long pointy beaks, while other birds have short flat beaks?

Evidence for the Theory of Evolution

Evidence for evolution can be found in:1. the fossil record2. the geographical distribution of living species3. homologous structures of living organisms4. similarities in early development, or embryology.5. molecular (DNA) homologies

1. Fossil record

By comparing fossils from older rock layers to fossils from younger layers, researchers have discovered many hundreds of transitional fossils that document various intermediate stages in the evolution of modern species from organisms that are now extinct.

2. Biogeography: study of the geographical distribution of plants and animalsDarwin observed this with finches and tortoises in the Galapagos Islands. He noticed that there were several different species of birds/tortoises on the islands that were similar to each other, but had different adaptations. He thought that they evolved from a common ancestor to best fit the environment of the island they were on.

We can see this in other species around the world too.

3. Homologous structures: bones and muscles that have similar structures but perform different functions

4. Embryonic Homologies: Different organisms develop from similar starting forms (embryos)

5. Molecular Homologies: similarities in DNA sequences among different organisms

Because organisms evolved from a common ancestor, we find similarities in the DNA sequence of all living organisms. The more of a DNA match we see, the closer of a relationship the organisms have.

Homework:

• Watch the video “Evidence of Evolution” from Bozeman Science. http://www.youtube.com/watch?v=cC8k2Sb1oQ8

• Write down 5 different examples of evidence for evolution

**There are two videos by Bozeman on this topic. Watch the 9 minute video!