1. Darwin & Determination
Evolution
Darwin & Determination

2. Theories before Darwin:
Spontaneous Generation
the idea that life arises from nonlife.
Theory of Biogenesis-
the idea that only living organisms can produe other living organisms.

3. Oparin – Haldane: primordial Soup and the Miller – Urey experiment

4. Endosybiotic theory

5. Theories before Darwin:
James Hutton – Geologic Change
stated that the earth is millions or billions of years old.
Jean-Baptiste Lamarck - Use or Disuse (use it or lose it)
stated that organisms either use characteristics or lose those characteristics.

6. Charles Darwin:
Born 1809
Born to a wealthy family (father was a doctor and member of aristocratic class).
Mother died when Charles was young.
Charles was a Naturalist and Entomologist.
Sent to Medical School at 18 and failed out at 19.
Went to Seminary school and received a degree in Divinity from Cambridge University.

7. Beagle set sail around the world in 1831 (Charles was 22 years old).
While there he became friends with John S. Henslow (botany professor) who set him up as Ship’s Naturalist on the H.M.S. Beagle.
Beagle set sail around the world in (Charles was 22 years old).
Stayed in the Galapagos Islands for a couple of weeks, then headed towards Asia.
Charles had been sending everything he collected back to Henslow in England.

8. The HMS Beagle’s Voyage Darwin returned 5 years later in 1836
Darwin Left England in 1831
The HMS Beagle’s Voyage
Darwin returned 5 years later in 1836

9. Blue-footed booby, photo courtesy of stirwise, flickr creative commons
Marine Iguana, photo courtesy of mtchm, flickr creative commons
Blue-footed booby, photo courtesy of stirwise, flickr creative commons

10. Finch, photo courtesy of stirwise, flickr, creative commons
Giant tortoise, photo courtesy of Planetgordon, flickr creative commons

11. Each was adapted to eating a particular type of island food
He concluded that all came from one ancestral species
Cactus finch, photo courtesy of zrim, flickr creative commons

12. Upon returning home, he found that he had become
Upon returning home, he found that he had become quite noted as a collector and a scientist and became a fellow of the geological society.
Spent two years arranging notes and specimens from the trip and displaying them for other scientists. Got married (Wedgwood Family).
Charles began to get ideas of a “transmutation” theory to explain some of the differences that he saw in animals.

13. He was urged to write a book about it and his travels.
In 1844 he wrote the manuscript for a book but didn’t want to publish.
In 1859, when others were coming up with similar theories, he published On the Origin of Species by Means of Natural Selection.
Charles Darwin died at his home in from a heart attack and was buried in Westminster Abbey.

14. Evolution: is the slow , gradual change in a population of organisms over time to survive; decent with modification

15. 1. Darwin traveled to which islands? 2. What was the name of his ship?
Checkpoint
1. Darwin traveled to which islands?
2. What was the name of his ship?
3. Name 4 species he observed on the islands.
4. He developed what theory?
5. This theory explained how organisms
_______________ over _________

16. Darwin’s Theory
1. Variation exists among individuals in a species. These traits are inherited.
2. Individuals will compete for resources
3. Competition would lead to the death of some, while others would survive
4. Individuals that had advantageous variations are more likely to survive and reproduce. .

17. Darwin called this
- Natural Selection
Those organisms that are best “fit” to the environment will survive the environment and reproduce.
Adaptation – a characteristic that an organism has that allows it to survive.
Extinction – all members of a population dying out due to not having beneficial adaptations.

18. What’s the point? Survival of the fittest:
If you outcompete other organisms for few resources you will live to pass on your genes.
Ex: Camouflage & mimicry

19. Fitness is the measure of if a trait will be passed on.
Camouflage
Mimicry
morphological adaptations to allow them to blend in with their environments
morphological adaptation where one species evolves to resemble another species

20. Say in a species of blob…
Say in a species of blob….there exists blobs of all shapes and sizes (variation)
Blobs eat the little purple organisms that live underground and on the surface.

21. During a particularly hot year, food became less abundant (competition), blobs that had the ability to dig into the soil to get food had a better chance of survival.
Many blobs died that year…….

22. The ones that survived mated and passed their genes to the next generation. (reproduction)

23. The next generation had more blobs with the pointed noses
The next generation had more blobs with the pointed noses. That is NATURAL SELECTION.
Variation
Competition
Survival
Reproduction

24. Artificial Selection - humans selected variations they found useful and bred animals and plants for those traits.

25. Much of our agriculture (food, animals, clothing) is a result of artificial selection that has occurred over many generations.
We can influence the EVOLUTION of a species

26. 1. What was the name of Darwin’s book?
Checkpoint
1. What was the name of Darwin’s book?
2. The theory states that
a) individuals of a species have differences, called_________
b) these individuals ________________ for resources
c) some will die, others will ____________________
d) survivors will _________________________ and pass traits to offspring
3. Any trait that helps an organism survive is called an _______________________________
4. When humans influence evolution be breeding for desired traits, it is called _______________________________

27. Evidence for Evolution

28. 1. Biogeography and Fossil Evidence shows…..
similarities between extinct animals and animals that are alive
earth’s layers, and species that lived at each time
Fossils found at lower layers of rock are simpler than those found at upper layers.

30. Dinosaurs have always fascinated us, movies such as Jurassic Park capitalize on that fascination.
How do we know what dinosaurs looked like?
We create a picture based on the bones we find (fossils) and use modern reptiles to guess at their texture and skin color.

31. 2. Comparative Anatomy
Homologous structures – these are parts of the body that are similar, but have different functions
Suggests common ancestry
All forelimbs of vertebrates have the same pattern of bones.
ex. The flippers of whales, and the wings of birds

32. Comparative Anatomy
Analogous structures: are UNLIKE homologous structures in that the structures appear similar but do not imply common ancestry.
EX: wings of a bird and wings of an insect.

33. Comparative Anatomy Vestigial Organs
Organs that are found in you that have no purpose in the body, but are found and used in other organisms.
1. You have an appendix.
2. Snakes have hipbones. 
3. Whales have hipbones too.

34. 3. Molecular biology (Biochemistry)
Segments of our DNA called genes are much like that of other species and provide evidence for Evolution and a common ancestor.

35. 4. Embryonic Similarities
All vertebrate organisms look similar during formation. Also, the process follows the same steps.

36. Checkpoint: With your partner, find the answers in your notes.
1. ____________ evidence shows when organisms lived on the earth
2. Species that are closely related will have similar _______
3. A _______________ organ is one that has no function.
4. _________________ structures look the same but have different functions, like the arm of a human and the flipper of a whale.
5. ____________ structures of different animals develop in the same way but do not have common ancestry.

37. The Theory of Evolution: Darwinism
We have discussed the 4 supporting evidences of evolution.
Biogeography
Comparative anatomy
Molecular Biology
Embryology
Now we are going to discuss the 4 mechanisms of HOW Evolution occurs…

38. #1 Natural Selection:
Natural Selection – AKA “Survival of the Fittest” A gradual, non-random process by which biological traits become either more or less common in a population
As you can see there is a variation in the phenotype of these beetles: Green or brown  

39. Genetic Variations – differences within a population
Increases or decreases an organisms chance of survival
Inherited and controlled by alleles
Allelic frequencies in a populations gene pool will change due to natural selection

40. Genetics Determines Evolution:
Gene Pool – All the alleles in a populations genes. In other words every form of a trait
Allelic Frequency – the % of any specific allele w/in a gene pool

41. Genetic Equilibrium – allele frequency remains the same over generations
Populations in genetic equilibrium are not evolving
Factors that affects genes can affect equilibrium
Mutations [negative, positive]
Negative more than likely causes death
Positive may be beneficial and passed on to future generations

42. The genetic variation in this scenario are the genes that code for the color of the beetle.

43. 3 Types of Natural Selection that Act on Variation:
1. Stabilizing Selection – natural selection that favors average individuals

44. 3 Types of Natural Selection that Act on Variation:
2. Directional selection – natural selection that favors an extreme form of a trait

45. 3 Types of Natural Selection that Act on Variation:
3. Disruptive selection – individuals w/ either extreme form of a trait

46. #2 Mutation
Mutation: change in a gene; alteration of a nucleotide sequence.
EX: A mutation causes two green beetle parents to have a brown beetle

47. #3 Migration
Migration: Movement of some individuals to another population
Gene Flow – transfer of alleles from one population to another population through immigration of individuals. This disrupts allele frequency.

48. #4 Genetic Drift
Genetic Drift: some individuals may by chance, and not because of “fitness,” leave more descendants and therefore pass on their genes.

49. Change can be simply a random thing.
Bottleneck Effect
- having an event that kills off members of a species randomly by chance.
Founder Effect
- a new colony is formed by a few members of the original population

50. Checkpoint: With your partner, use your notes to find the answers.
1. ____________ ______________ is also known as survival of the fittest.
2. Three types of natural selection act on variation:
a. ______________
b. ______________
c. ______________
3. _________________ are changes in the amino acid sequence of gene and can have positive or negative outcomes.
4. ________ _________ occurs when individuals of genes move to another population.
5. Sometimes individuals pass on their genes due to chance rather than fitness resulting in ____________ _________.

51. So how do new species come about?

52. The Evolution of Species:
Species – organisms that look alike can interbreed to produce fertile offspring
Speciation – evolution of a new species.
*NOTE: Organisms within the same species have reproductive success ( ability to pass genes onto the next generation in a way that they too can pass on those genes.)
Mule
Donkey
Horse
He can not have offspring because his parents are two different species 
This is NOT a reproductive success + =

53. Physical Barriers Cause Speciation:
1. Geographic Isolation – a physical barrier divides a population

54. Genetic material becomes so different fertilization cannot occur
2. Reproductive Isolation – the inability of organisms to mate and breed fertile offspring
Genetic material becomes so different fertilization cannot occur
Behavior – mating seasons are different
These Bowerbirds have different mating seasons and rituals. These 2 factors contribute to Reproductive Isolation

55. Shifts from the Average Cause Speciation:
Directional Selection
Stabilizing Selection
Disruptive Selection

56. Does evolution happen fast or slow?

57. Speciation Rates - the time it takes for evolution to occur.
2 Theories:
#1 Gradualism: – idea that species originate through a gradual change of adaptations

58. # 2. Punctuated Equilibrium : things staying the same for a period of time then rapidly changing due to a catastrophic event.

59. Gradualism vs. Punctuated Equilibrium

60. There are TWO types of Evolution

61. #1 Divergent Evolution – accumulation of differences between groups which can lead to the formation of new species

62. Adaptive Radiation – ancestral species evolves into an array of species to fit a particular environment or niche.

63. #2 Convergent Evolution – organisms not closely relate, independently evolve similar traits (to adapt to similar environments.)

65. Macroevolution When one species is replaced by another species.
Australopithocene skull
Homo Sapien Skull

66. Microevolution Species giving rise to several different species.
All citrus came from an original species of citrus tree