1. Speciation
Chapter 15

3. Vocabulary Ch 15 Adaptive radiation Vestigial Structure
Homologous structure
Gene pool
Mimicry
Camouflage
Natural Selection
8. Stabilizing Selection
9. Disruptive Selection
10. Directional Selection
11. Artificial Selection
12. Polyploid
13. Punctuated Equilibrium
14. Allelic Frequency
15. Genetic drift

4. The two populations no longer interbreed since the two populations can’t get together.
They evolve different traits due to natural selection.

5. Reproductive Isolation
Two populations cease interbreeding due to behavior changes or differences in genes.
Different mating seasons.
Genes become so different that an embryo fails to form.

6. Reproductive Isolation
Happens between two polyploids, except for wheat, cotton, apples, and bananas.
Two species will not breed anymore because their genes are too different.

7. Genetic Drift
A change in allele frequency in a population.

8. Stabilizing Selection
Average trait species are favored to survive
Trait types (beak type)
Population

9. Average-size spiders survive predators Birds catch the big spiders
Average-size spiders survive predators Birds catch the big spiders. Small spiders die from competition.

13. Directional Selection
Species with extreme traits are favored to survive.
Woodpecker with long beak gets the worm in the tree, those with short beaks die off.

14. Directional Selection
One extreme of the trait is favored to survive in a population
Due to environment and predator pressure.

15. Long beaked birds get food from a deep lake, while short beaked birds can’t reach the bottom of the lake and perish.

17. Disruptive Selection
Two Extreme traits (either short or long) favored for survival over the average trait
Light and Dark limpets (type of snail) survive because they can camouflage themselves on light and dark rocks.

18. limpets

22. Geotaxis
Preference of flies to fly up straight, or down to get to food.

23. Founder Effect

24. Sexual Selection
Peacocks have long feathers to show peafowl they can produce healthy offspring.
Longest feathered males will be chosen to mate.
Short feathered males will die off.

25. Adaptive Radiation
A common ancestor develops into different species. Different species fill different niches.
Galapagos finches change beak size depending on food types.
Different types of honeycreeper birds in Hawaii

27. Divergent Evolution
Species that once were similar to an ancestral species diverge and become distinct in appearance

29. Divergent Evolution
Hummingbird species beaks have shown an increase in size, depending on the flowers they get nectar from.
Larger beak hummingbirds no longer mate with short beak birds

30. Convergent Evolution
Different organisms living in different places on earth, but in similar environments, evolve similar traits due to similar natural selection pressures.
They fill similar niches but are different species

32. Pika and groundhog

33. Similar Plant on different continents Organ Pipe Cactus and the Euphorbia African Cactus

34. Sharp Teeth/ Predators
Shark in oceans & tiger in Asia

35. Browsers, Long Ears
Deer from North America and kangaroos from Australia

36. Scavengers
Coyote & Golden Eagle

37. Speciation

38. Sympatric speciation
Evolves into new species without barriers to reproduce

39. Allopatric speciation
A barrier separates two populations and they don’t interbreed.

40. Gradualism
Hypothesis that species gradually evolve over time.

41. Punctuated Equilibrium
Hypothesis that species change when a disaster strikes, like Dinosaur Extinction at the Mesozoic Era.