1

Evolution Part I

BIO 2215Oklahoma City Community CollegeDennis Anderson

2

Evolution

• Changes in a population over time

3

Does the idea of evolution contradict a belief in God?

• Many scientists of all religious faiths believe in both.

• Some people feel evolution contradicts the literal interpretation of the Bible.

4

Earths Position in the Universe

• 400 years ago the general public thought that the earth was the center of the universe– Sun revolves around

the earth

– The earth does not move

5

Galileo and Corpernicus

• Demonstrated scientific evidence that the sun is at the center of our solar system and the earth moves around the sun

6

Galileo and the Church

• Religious leaders felt the heliocentric theory (sun at the center) was a direct contradiction to the literal interpretation of the Bible

• Galileo found guilty of heresy

7

Copernican System (Heliocentral Theory)

• Did not destroy peoples belief in God

• Public now accepts the overwhelming evidence for the heliocentric theory

8

Theory of Evolution

• Science has overwhelming evidence that all life is constantly evolving

9

Charles Darwin 1809-1882

10

HMS Beagle 1831-1836

11

Ostrich in Africa Rhea in South America

12

13

14

15

Adaptive Radiation

16

Land Iquana

17

Marine Iquana

18

Different Tortoises on Each Island

19

Origin of Species 1859

20

Natural Selection

• One mechanism of evolution

• Main concepts of natural selection– Overproduction of offspring– Inherited variation in offspring– Competition – Best adapted in a given environment survive

and reproduce to increase their kind• They are naturally selected

21

Overproduction of Offspring

• Elephants (very slow reproductive rate)– If all the offspring of one elephant pair survive and all

their offspring survive then:• 750 years = 19,000,000 elephants• 1200 years = Enough elephants to cover the earth!

• Beetles– A handful that weighs 10 mg each– 82 weeks

• 61,000,000,000,000,000,000,000 ton– The weight of the earth!

22

Variation of Offspring

• Offspring of the same parents are different from each other

23

Competition

• Since more individuals are born than can survive for an extended period of time, they compete for resources– Food– Living space– Mates

24

Best adapted to a given environment are selected to survive

• Brown bears– Adapted to survive in

Oklahoma

• Polar bears– Adapted to survive in

Alaska

25

Artificial Selection

Collie Sheltie

26

Evolution is Change• Changing alleles in a population can

produce new species

• Dogs have evolved from wolves

• Man has artificially selected traits to produce the various dog breeds

• Nature uses natural selection and other mechanisms for evolution

27

Natural Selection of

Flies

28

• Natural Selection

29

Scientific Disciplines That Give Evidence for Evolution

• Paleontology

• Comparative anatomy

• Biogeography

• Molecular biology

• Others

30

Paleontology

• Study of fossils – Allows us to see

anatomical similarities between living species and organisms that lived in the past

– Allows us to see how life has changed over time

31

Life Has Changed

• Millions of species have been found that are different from life today

32

Horse Evolution

33

50 Million Years of Change

50 MYA 30 MYA 15 MYA Modern

34

Florida Museum of Natural History

35

• Whale evolultion

36

Comparative Anatomy

37

Homologous Structures• Same structures used for different purposes

38

Homologous Structures

39

HomoplasyAnalogous Structures

Similar structures due to convergent evolution,

40

Biogeography

41

Why No Polar Bears in Antarctica or No Penguins in Arctic?

42

Why marsupials in Australia?

43

44

Molecular Biology

• The study of the molecules of life including DNA and proteins

45

DNA Similarity

46

Homeobox or HOX

• First discovered in fruit flies in 1983

• Later found in mice, man and other organisms

• Controls embryonic development of different body regions

47

Evolution of New Body Plan

• Hox gene Ubx of crustacean mutated in lab

• Caused suppression of leg development

• Mechanism for evolution of insect body plan 400 MYA

48

• Homeobox genes

49

Comparing DNA

• Human DNA compared to:– Chimpanzee 99% same

– Gorilla 97.7% same

– Orangutan 96.3% same

– Another human 99.9% same

50

Comparing Protein Sequences

• Many proteins in all of man are identical

• Organ transplants require similar proteins in the donor and the recipient– A sibling or parent is often the best source for

an organ transplant

51

Which would be the closest protein match for an organ transplant?

Assuming all are alive and healthy.

• A persons father

• A persons great grandfather

• A persons 10th great grandfather

52

Molecular Clock

• The further you go back in time, the more proteins (and DNA) are different.

• Differences in protein sequences and DNA can be used to estimate time when two species shared a common ancestor

53

Related Organisms

• Close similarity of protein sequences indicates close relationship

54

Cytochrome C

• Protein used to release energy from food

• 104 amino acids• 20 of the amino acids

occupy the same position in all eukaryotes

55

Comparison of Human Cytochrome C

• 100 amino acids different in tuna fish

• 12 amino acids different in a horse

• 8 amino acids different in a kangaroo

• 1 amino acid different in a monkey

• Identical to chimpanzee

56

Pattern of Evolution Originally Based on Fossil Record

• DNA comparisons confirm the same pattern

• Protein sequences confirm the same pattern

• 150 years of research by thousands of scientists demonstrate beyond doubt that life evolves.

57

The End