Evolutionary Adaptations and the Scientific Method

1. Chapter 10 Evolution Powerpoint #2 Pg278

2. Scientific Method: • Problem • Hypothesis- Statement that can be tested- what you think will happen… • Experiment- Testing a hypothesis using a series of steps with controlled conditions • Conclusion- Was the problem solved? • Theory- A hypothesis that has been tested again and again & received similar results each time

3. Lab #1: Problem How is color an adaptation? This lab we will be conducting at the end of class after we have learned some key evolutionary concepts. You need to understand all of the steps of the Scientific Method in order to be successful in your first lab!

4. pg 284How do scientists explain the fact that living things are well suited to where the live? Adaptations What is adaptation?

5. Adaptation: A trait that makes a living thing able to survive in its surrounding Example of an adaptation: Webbing bw the toes of a bird How does this help the bird? The bird can swim faster. The webbing creates more surface area, allowing the bird to apply more force against the surrounding water. 

6. How do adaptations help living things survive? Mice & Owls Key Vocab Word: Unfavorable trait

7. A group of mice live in an area that has dark soil. Owls that eat mice also live in this area. Because dark mice blend well with the dark soil, owls cannot see them easily. Thus the dark mice are better protected because they blend with the soil color. Their color is an adaptation, a trait that helps them survive. Being a white mouse in this area would be considered a unfavorable trait.

8. Lab Time!!!

9. Today’s Agenda:1. Finish Collecting Lab Data2. Discuss Post-Lab Questions Briefly3. Topic Natural Selection4. Discuss Peppered Moth Study

11. The Peppered Moth Study The peppered moth study is a perfect case study of natural selection in action. • In the early 1800s, a common moth species in England had light-colored peppered wings, which helped it blend in with the light bark on the trees in the area. • This camouflage trait helped the moth avoid being eaten by birds. • In 1848, a new dark form of the moth began appearing, and by the turn of the century, the dark variety made up the vast majority of the moth population.

12. So what happened? Why did the light moths die off, while the dark ones flourished? • Something must have changed that gave the dark moths a survival advantage. • Scientists recognized that moths were changing in response to a change in their environment. • Extensive air pollution from industrialization was causing the tree bark to darken with coal soot.

13. The Peppered Moth Study 1) Overproduction 2) Inherited Variation Traits for light or dark color are passed on genetically, and moth offspring tend to have traits similar to their parents. However, within a population, some are lighter and some are darker. Peppered moths lay many eggs, and out of those that hatch, the vast majority of them will be eaten and will not survive to lay eggs of their own. 3) Competition 4) Reproduction Since there are so many moths, some will survive, but most will die. The ones that survive tend to be the ones that have traits favorable for survival, in this case, camouflage. The moths that best blend in with their surroundings will be more likely to survive to adulthood and lay eggs, which will yield offspring with those same favorable camouflage traits.

14. Peppered Moth Can you spot the moth? • Keep in mind: • No individual moth ever changed its color. Some moths simply survived better than others, changing the allele frequency, therefore changing the appearance of the color traits among the entire population. • In other words, the light moths didn’t become darker. They just tended to die out, allowing the dark moths to take over!

15. Peppered Moth Can you spot the moth? • Keep in mind: • No individual moth ever changed its color. Some moths simply survived better than others, changing the allele frequency, therefore changing the appearance of the color traits among the entire population. • In other words, the light moths didn’t become darker. They just tended to die out, allowing the dark moths to take over!

16. Carrier Cc Dominant CC Recessive cc Allele When two carriers mate: Ratio of Offspring: Dominant: ¾ 75% Recessive: ¼ 25% Allele- Variant of a gene

17. Carrier Bb Dominant BB Recessive bb When a recessive & carrier mates: Ratio of Offspring: Dominant: ½ 50% Recessive:½ 50%