1. How did life begin? Miller and Urey’s Experiment
Passed sparks through a mixture of hydrogen methane ammonia and water
This produced amino acids – the building blocks of life

2. E N D O S Y M
B T
I H
O E
T O
I R
C Y

3. Theory of Life cont. Endosymbiotic theory
eukaryotic cells arose from living communities formed by prokaryotic organisms
Ancient prokaryotes entered primitive eukaryotic cells and remained there as organelles

5. Lamark Theory of acquired characteristics
Lamark said organisms acquired traits by using their bodies in new ways
These new characteristics were passed to offspring
Lamark was totally wrong!

6. Geologists: Hutton and Lyell
Fundamentalists said that the earth was around 6000 years old
Hutton and Lyell argued that the earth is many millions of years old b/c
layers of rock take time to form
processes such as volcanoes and earthquakes shaped the earth and still occur today

7. Malthus
Reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone

9. Charles Darwin (1809-1882) Sailed around the world 1831-1836

10. 2. What did Darwin’s Travels reveal
The diversity of living species was far greater than anyone had previously known!!
These observations led him to develop the theory of evolution!!

11. 3.How did tortoises and birds differ among the islands of the Galapagos?
Warbler finch
Woodpecker finch
Small insectivorous
tree finch
Large
insectivorous
Vegetarian
Cactus finch
Sharp-beaked finch
Small ground
finch
Medium
ground finch
Large ground
Insect eaters
Bud eater
Seed eaters
Cactus
eater
Warbler
Tree finches
Ground finches

12. Galapagos Tortoises

13. Evolution is when organisms change over time
Evolution is when organisms change over time. So, modern organisms descended from ancient ones

14. Evolution is a Theory – Just like Gravity!
Evolution is a well supported explanation of phenomena that have occurred in the natural world
A theory in science must be supported by facts, it can’t be based on supposition.

15. Darwin finally published his ideas in 1859
Only when other naturalists were developing the same theory that he had did Darwin finally publish his findings.

16. Artificial Selection
nature provides variation, humans select variations that are useful.
Example - a farmer breeds only his best livestock

17. Natural Selection
The traits that help an organism survive in a particular environment are “selected” in natural selection

18. What color genes are in the beetle gene pool?

19. What’s happening to the color genes in the
beetle gene pool?
Why is this happening?

20. Explain why we say green beetles have been
selected against while brown beetles have
been selected for?

21. Natural Selection and Species Fitness
Overtime, natural selection results in changes in the inherited characteristics of a population.
These changes increase a species fitness (survival rate)
Bottom line:
Those that are best adapted to their environment survive to reproduce.

22. Evidence of Evolution Fossil Record
Geographic Distribution of Living Species
Homologous Body structures
Similarities in Embryology
Vestigial organs

23. Evidence of Evolution
Fossil Record provides evidence that living things have evolved
Fossils show the history of life on earth and how different groups of organisms have changed over time

24. Primate Fossils
Australopithecus Homo erectus Homo sapien

25. Remember PANGEA?

26. Evidence of Evolution Geographic Distribution of Living Species
Similar animals in different locations were the product of different lines of descent

27. Evidence of Evolution Analogous Structures are the result of
Geographic Distribution of Living Species
Analogous Structures
are the result of
convergent evolution
Similar animals in different locations exhibit analogous structures due to similar environmental pressures.
Eg. North American flying squirrel and the Australian sugar glider

28. This means they are analogous structures.

29. Convergent evolution Fish: aquatic vertebrates
Dolphins: aquatic mammals
similar adaptations to life in the sea
not closely related
Those fins & tails
& sleek bodies are analogous structures!

30. Evidence of Evolution Adaptive radiation leads to
Homologous Body Structures thru divergent evolution
Structures that have different mature forms but develop from the same embryonic tissues
e.g. Wing of bat, leg of turtle & human arm, are similar by de- scent not function.
Turtle
Alligator
Bird

31. Convergent evolution Fish: aquatic vertebrates
Dolphins: aquatic mammals
similar adaptations to life in the sea
not closely related
Those fins & tails
& sleek bodies are analogous structures!

32. Homologous Body Structures…………
…………are the result of divergent evolution

33. 13. Evidence of Evolution Similarities in Embryology
In their early stages of development, chickens, turtles and rats look similar, providing evidence that they shared a common ancestry.

34. Embryological development

35. Vestigial organs
Modern animals may have structures that serve little or no function
remnants of structures that were functional in ancestral species
evidence of change over time
some snakes & whales show remains of the pelvis & leg bones of walking ancestors
eyes on blind cave fish
human tail bone
This is not LaMarck’s loss from “disuse”!

36. Vestigial Structures
in snakes

37. Vestigial Structures
in whales

38. Molecular record Comparing DNA & protein structure
universal genetic code!
DNA & RNA
compare common genes
cytochrome C (respiration)
hemoglobin (gas exchange)
Why compare these genes? 25 50 75
100
125
Millions of years ago
Horse/
donkey
Sheep/
goat
Goat/cow
Llama/
cow
Pig/
Rabbit/
rodent
Horse/cow
Human/rodent
Dog/
Human/
Human/kangaroo
Nucleotide substitutions
Closely related species have sequences that are more similar than distantly related species
DNA & proteins are a molecular record of evolutionary relationships

39. Comparative hemoglobin structure
Human
Macaque
Dog
Bird
Frog
Lamprey
Why does comparing amino acid sequence measure evolutionary relationships? 8 32 45 67
125 10 20 30 40 50 60 70 80 90
100
110
120
Number of amino acid differences between
hemoglobin (146 aa) of vertebrate species and that of humans

40. Descent with Modification
Each living species has descended with changes from other species over time

42. Summary of Darwin’s Theory
1. Organisms differ; variation is inherited
2. Organisms produce more offspring than survive
3. Organisms compete for resources
4. Organisms with advantages survive to pass those advantages to their children
5. Species alive today are descended with modifications from common ancestors

43. Variation in Populations
2 processes can
lead to this:
Mutations -
change in DNA
sequence
Gene Shuffling –
from sexual
reproduction

44. Gene Pool Combined genetic info. of all members
Allele frequency is # of times alleles occur

45. Genetic Drift changes populations…
Random change in allele frequency causes an allele to become common

46. Founder Effect: a cause of genetic drift attributable to colonization by a limited number of individuals from a parent population

47. Evolution of Populations
Occurs when there is a change in relative frequency of alleles……….
in other words – a change in the contents of the gene pool

48. Gene Flow: genetic exchange due to the migration of fertile individuals or gametes between populations (reduces differences between populations)

49. Nonrandom mating aka artificial selection: inbreeding and assortive mating (both shift frequencies of different genotypes)

50. Natural Selection: differential success in reproduction; only form of microevolution that adapts a population to its environment

51. Single-Gene vs. Polygenic Traits
2 Distinct Phenotypes
Polygenic:
Many Phenotypes
(EG: tongue rolling)

52. Natural Selection on Polygenic Traits
Shifts to
middle range
2 extremes
1 extreme

53. Are you more closely related to a turtle or a frog?

54. Natural selection in action
Insecticide & drug resistance
insecticide didn’t kill all individuals
resistant survivors reproduce
resistance is inherited
insecticide becomes less & less effective
The evolution of resistance to insecticides in hundreds of insect species is a classic example of natural selection in action.
The results of application of new insecticide are typically encouraging, killing 99% of the insects.
However, the effectiveness of the insecticide becomes less effective in subsequent applications. The few survivors from the early applications of the insecticide are those insects with genes that enable them to resist the chemical attack. Only these resistant individuals reproduce, passing on their resistance to their offspring. In each generation the % of insecticide-resistant individuals increases.