1. The Theory of Natural Selection
No. The white rabbits died. Since the green survived better they reproduced more.
Did the white rabbits turn green?
Which rabbits are best adapted (more likely to survive and reproduce)?

2. Artificial Selection
Humans have shown that breeding can cause changes over time
Dogs, Crops, Livestock
Dog traits have been selected by breeders for centuries to enhance certain traits.

3. Artificial Selection
Humans have shown that breeding can cause changes over time
Dogs, Crops, Livestock
Wild mustard has been bred by farmers into numerous other foods

4. Artificial Selection
Humans have shown that breeding can cause changes over time
Dogs, Crops, Livestock
Pigeons have been bred to enhance tail feathers….breast feathers…etc…

5. Artificial Selection video clip:
Humans have shown that breeding can cause changes over time
Dogs, Crops, Livestock
Defined: Humans (not nature) have selected desirable traits
Importance? Shows that breeding can lead to change over a period of time
Artificial Selection video clip:
Carl Sagan’s Cosmos

6. Pretend these are insects in a desert. Will they all survive?
Natural Selection
Pretend these are insects in a desert. Will they all survive?
Four factors:
1) Overpopulation: more offspring are born than can survive

7. Variations: Size, Color, Shape
Natural Selection
Variations: Size, Color, Shape
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences

8. Natural Selection Four factors:
Will some have advantages to help them survive hunting birds and spiders?
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival

9. Disadvantages: Dark color
Natural Selection
Disadvantages: Dark color
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

10. Disadvantages: Large size
Natural Selection
Disadvantages: Large size
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

11. Disadvantages: Contrasting color
Natural Selection
Disadvantages: Contrasting color
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

12. Disadvantages: Square shape
Natural Selection
Disadvantages: Square shape
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

13. Natural Selection Four factors:
Will all these individuals survive?
Those with advantages… reproduce with each other.
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

14. Natural Selection Four factors:
fatter
faster
Bigger antlers
Gets tired quicker
Will all these wildebeest survive the African plains?
shorter
No. There is a struggle to survive.
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

15. Natural Selection Four factors:
smaller
Poor eyesight
Brighter colors
Deformed fin
Will all these fish survive in the ocean?
Faster metabolism
No. There is a struggle to survive.
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

16. Natural Selection Four factors:
Grows faster
Softer wood
Produces less chlorophyll
Stores less water
taller
Will all these trees survive in this forest?
No. There is a struggle to survive.
Four factors:
1) Overpopulation: more offspring are born than can survive
2) Variation: individuals of a population have differences
3) Adaptation: Some variations allow a better chance of survival
4) Descent w/ modification: Over time, those with advantages make up most of the population

17. Struggle for Survival
Humans will not be able to continue this extreme amount of growth forever.
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

18. Struggle for Survival 30 Seconds: Discuss with your neighbor:
What are some examples of limiting factors?
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

19. Struggle for Survival
Limiting factor examples:
Predation
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

20. Struggle for Survival
Limiting factor examples:
Predation
Competition
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

21. Struggle for Survival
Limiting factor examples:
Predation
Competition
Clean water
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

22. Struggle for Survival
Limiting factor examples:
Predation
Competition
Clean water
Disease
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

23. Struggle for Survival
Limiting factor examples:
Predation
Competition
Clean water
Disease
Shelter
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

24. Struggle for Survival
Limiting factor examples:
Predation
Competition
Clean water
Disease
Shelter
Acts of Nature
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth

25. Struggle for Survival
Humans have high fitness.
That’s why our population is growing exponentially.
Limiting Factors prevent populations from growing forever
Limiting Factors: factors that slow or stop population growth
The more fit an organism, the more likely it is to survive
Fitness: measure of the ability to survive & produce more offspring
As environments change…
Those with adaptation: more likely to survive & reproduce
Those without adaptation: more likely to perish

26. Fitness & Natural Selection
This species of insect resembles a leaf.
What happened to the individuals that lacked this variation?
They died

27. Fitness & Natural Selection
This species of caterpillar resembles bird poop.
What happened to the individuals that lacked this variation?
They died

28. Fitness & Natural Selection
The bright colors of this frog species serves as a poisonous warning.
What happened to the individuals that lacked this variation?
They died

29. Fitness & Natural Selection
This cactus species has sharp thorns to ward off herbivores.
What happened to the individuals that lacked this variation?
They died

30. Fitness & Natural Selection
This giraffe has a long neck to better reach food.
What happened to the individuals that lacked this variation?
They died

31. The Myth
The Truth
Individuals don’t grow something because they need it.
Individuals don’t evolve.
Natural selection can act only on traits that already exist

32. Which rabbit is best adapted?
Do the dark rabbits turn white? No! They get eaten.

33. Evolution Video Part IV: How Does Evolution Really Work?

34. Sexual Selection Defined: a trait that increases mating success.
Ex: Bright coloring or large antlers
There are two types:
Intrasexual selection: competition among the same sexes (males vs. males)
Intersexual selection: males display certain traits to females
Mating can have an important effect on the evolution of a population
Occurs due to higher cost of reproduction for females.
Males produce many sperm continuously
Females are limited in the number of offspring they can produce

35. Constant creation of chemicals for human use is eliminating the “unfit” organisms
Ex: Antibiotics eliminating unfit bacteria
Resistant
Organisms
Alexander Fleming discovered the first antibiotic… penicillin

36. Constant creation of chemicals for human use is eliminating the “unfit” organisms
Ex: Antibiotics eliminating unfit bacteria
Resistant
Organisms
When infected with a bacteria, we take antibiotics.
The antibiotics are absorbed into the bacteria.
Bacteria A is more likely to survive and _________________.
REPRODUCE
Bacteria A
Bacteria B
antibiotic
antibiotic
Bacteria A
antibiotic
antibiotic
antibiotic
antibiotic
antibiotic
antibiotic
Bacteria A has genes to create enzymes that destroy the antibiotic
Bacteria B does not have the genes to make the enzymes to destroy the antibiotic

37. Constant creation of chemicals for human use is eliminating the “unfit” organisms
Ex: Antibiotics eliminating unfit bacteria
Resistant
Organisms
30 seconds: Discuss with your neighbor
If you were infected with this bacteria, which antibiotics could be used to treat your infection?
This Petri dish has bacteria growing on it. The bacteria appear as the brown smears on the background of the Petri dish.
The 5 white discs have been treated with 5 different antibiotics.
There’s no bacteria surrounding kanamycin and amoxycillin. This means that kanamycin and amoxycillin are killing the bacteria.
penicillin
kanamycin
ampicillin
tetracyclin
amoxycillin

38. Antibiotic Resistance
Most bacteria killed
Strong Survive
Antibiotic Resistance
Strong Reproduce

39. Constant creation of chemicals for human use is eliminating the “unfit” organisms
Ex: Antibiotics eliminating unfit bacteria
Ex: Pesticides eliminating unfit pests
Resistant
Organisms

40. Constant creation of chemicals for human use is eliminating the “unfit” organisms
Ex: Antibiotics eliminating unfit bacteria
Ex: Pesticides eliminating unfit pests
Resistant
Organisms

41. Constant creation of chemicals for human use is eliminating the “unfit” organisms
Ex: Antibiotics eliminating unfit bacteria
Ex: Pesticides eliminating unfit pests
Resistant
Organisms
Some pests are able to resist the pesticides and survive. They will reproduce with others who are resistant. Over time, the entire population is resistant.
Pesticides pesticides pesticides pesticides pesticides pesticides

42. Constant creation of chemicals for human use is eliminating the “unfit” organisms
Ex: Antibiotics eliminating unfit bacteria
Ex: Pesticides eliminating unfit pests
Ex: Antivirals…
Ex: Fungicides…
This is natural selection!
Allows resistant organism to survive and reproduce
Resistant
Organisms

43. Evolution Video Part VI: Why Does Evolution Matter Now?

44. Review What is artificial selection?
What is natural selection? (Describe the 4 factors)
How does natural selection lead to population changes?
Why don’t populations (such as deer) continue to grow unchecked?
Compare the two different types of sexual selection.
Explain how antibiotic and pesticide resistance show natural selection.