SC300 Unit 6: Natural Selection• Unit 6 Assignment

• The dreaded letter ‘e’

• What is evolution?

• What is the genetic material?

• What role does genetic material play in evolution?

• How do populations evolve (undergo genetic change)?

• What is natural selection?

• The Beetle Experiment

• What is reproductive isolation?

• Selective pressures on squirrels

Unit 6 Assignment: A Borderless Society• For this assignment, think about the impact that two (2) of your meals have on our

world from an ecological and economic perspective. You can pick breakfast, lunch or dinner, and then answer the following questions. in 1,000-words, using APA style formatting, including all appropriate citations:

• List all of the components of two of your meals. Then, o Where did each component of your meal originate? List the country that each

part of your meal came from. (i.e., Did that glass of red wine come from Australia? Is the cheese from France?)

o List where you purchased the products from. o Consider the chain of events that took the product to get from the farm/laboratory

to your table. • What are some of the benefits of a global market and why? List at least 2 benefits,

weighing any short-term and long-term impacts.• What are some of the impacts of this global market and why? Considering both

short-term and long-term impacts, provide at least 2 negative impacts.• Consider the phrase Think Globally, Act Locally. What does it mean to you?• Has your research on the global market changed the way you will choose goods in

the future? Why or why not?

Wathr (Weather without E)

For this seminar, you will simulate an example of natural selection with the words you use. When your instructor announces "START," you should have a chat about the weather in your area. The only hitch is that you may not use the letter 'e' in anything that you type. Any words that contain the letter 'e' will be ignored. You and your classmates will talk about the weather in your area for five minutes total, after which your instructor will announce "STOP," and you will be allowed to use the letter 'e' again.

Your instructor will act as the predator. If you use the letter ‘e’ and your instructor notices, you will be tossed out of the game! So do your best to avoid the letter ‘e’.

What is evolution

Evolution is the change in groups of organisms over the course of generations. The changes in populations that are considered evolutionary are those that are passed via the genetic material from one generation to the next (Futuyma, 2009)

Futuyma, Douglas J. (2009). Evolution. Sinauer Associates Inc., Sunderland, MA.

What is the Genetic Material?

Ribonucleic Acid (RNA)Temporary copy of a gene

Normal Hemoglobin Protein

Sickle Cell Hemoglobin Protein

Hemoglobin Gene

What role does genetic material play in evolution?• Let Hb = Normal Hemoglobin Allele; HbS = Sickle Hemoglobin Allele

• Each person has two alleles (one from mom, the other from dad):

• Hb/Hb = Normal Red Blood Cells

• Hb/HbS = Some normal/some abnormal Red Blood Cells

• HbS/HbS = Sickle-shaped Red Blood Cells

• At age 10, about 92-94% probability of survival to age 20 (compared with 98-99% probability for Hb/Hb individuals)

• At age 20, females have about 86% probability of survival to age 30; males have about 82% probability of survival to age 30 (compared to 97% (females) and 96% (males) probability for Hb/Hb individuals).

Data from Platt, O.S., Brambilla, D.J., Rosse, W.F., Milner, P.F., Castro, O., Steinberg, M.H., and Klug, P.P. 1994. Mortality in sickle cell disease--life expecatncy and risk factros for early death. New England Journal of Medicine 330: 1639-1644

• Hb/HbS individuals appear to have increased resistance to malaria compared to Hb/Hb individuals.

http://sickle.bwh.harvard.edu/malaria_sickle.html

How do populations evolve (undergo genetic change)?

• Mutation: Random errors in DNA replication or DNA repair

• Gene Flow: Immigration into or emigration out of a population

• Nonrandom Mating: Selection for short, weak, big-nosed males!

• Random Genetic Drift: Effects of random events (important in small populations)

• Natural Selection

What is Natural Selection?Changes in the genetic structure of populations due to differential survival and reproduction.

1. More are born than can survive and/or reproduce.

2. There is genetic variation for phenotypes (characteristics) that affect survival and/or reproduction.

3. Those individuals with phenotypes that are best suited to the environment will be most likely to survive and reproduce.

4. The next generation will have a higher percentage of the best-fit individuals and a lower percentage of less-fit individuals.

The Beetle ExperimentGo to the Unit 6 Seminar information and click on: http://www.wiley.com/college/test/0471787159/biology_basics/animations/evolution.html

1. Next, click on the Natural Selection tab.

2. Then, click on the Experiment tab.

3. Play the Green Beetle-Brown Beetle game.

The Beetle Experiment

What is Reproductive Isolation?

For the beetles, how would reproductive isolation come about?

Give other examples of reproductive isolation?

Squirrels?

Think about this experiment as a way to show how changes in environment force creatures (like you) to adapt and change.

Now, think about squirrels. What might happen to them if all the oak trees (and therefore acorns) died out? What adaptations might they have to make to adjust to the acorn-free world? How might these changes affect their body structures? After 50,000 years of living in an acorn- free world, how might squirrels look? Why does this kind of evolutionary change take so long?