1. Evolution Chapters 21-25

2. Evolution (chapter 22)
Change over time in the genetic composition of a population
Descent with modification

3. Evolution history 1809 Lamarck publishes his hypothesis of evolution.
1798
Malthus publishes
“Essay on the Principle
of Population.”
Sketch of a flying
frog by Wallace
1812
Cuvier publishes his
extensive studies of
vertebrate fossils.
1858
While studying species in the
Malay Archipelago, Wallace
(shown above in 1848) sends
Darwin his hypothesis of
natural selection.
1795
Hutton proposes
his principle of
gradualism.
1830
Lyell publishes
Principles of Geology.
1790
1870
1809
Charles Darwin
is born.
1831–1836
Darwin travels
around the world
on HMS Beagle.
1859
On the Origin of
Species is published.
Figure 22.2 The intellectual context of Darwin’s ideas
1844
Darwin writes his
essay on descent
with modification.
Marine iguana
in the
Galápagos
Islands

4. Evolution History Aristotle “Scala naturae”
Organisms arranged in increasing complexity
Each form of life was permanent

5. Evolution History Linnaeus Taxonomy Naming & classifying organisms
Binomial system (Genus & species)
Grouping similar species in general categories

6. Evolution history Georges Cuvier Paleontology Study of fossils
Noted species in some layers of rocks
Each layer represented catastrophic events

7. Sedimentary rock layers (strata) Younger stratum with more recent
Figure 22.3 Formation of sedimentary strata with fossils
Younger stratum
with more recent
fossils
Older stratum
with older fossils

9. Evolution history Hutton
Change can take place through cumulative effect
Slow but continuous processes
Gradualism

10. Evolution history Lyell Geological processes are happening now
As they were in the past

11. Evolution history Lamacrk Two principles 1. Use and disuse
Parts of the body used became stronger
Those not used deteriorate

12. Lamacrk 2. Inheritance of acquired characteristics
Giraffes stretched necks to reach the leaves
Pass on the stretched neck

13. Figure 22.4 Acquired traits cannot be inherited

14. Charles Darwin

15. Darwin’s voyage

16. Darwin’s voyage

17. Darwin’s voyage

18. Darwin’s voyage

19. Darwin’s voyage Observed adaptations of many species Collected fossils
Resembled animals living in S. America
Collected different species of birds from Galapagos Islands
Species on the island were similar to the species only on SA mainland

20. Finches

21. Darwin’s voyage Conclusion Birds adapted to environment to survive
Adapted to food source that is available

22. Darwin Adaptation Accumulation of inherited characteristics
Enhance an organism’s ability
to survive & reproduce
in specific environment
Result of natural selection

23. Adaptation

24. Adaptation

25. Figure 22.1 How is this caterpillar protecting itself from predators?

26. Fig a
(a) A flower mantid
in Malaysia

27. Fig b
(b) A stick mantid
in Africa

28. Wallace Developed a theory of natural selection similar to Darwin’s
Forced Darwin to publish his writings

29. Charles Darwin November 24, 1859 Origin of Species
Focused on diversity of animals
Origins & relationships
Similarities & differences
Geographic distribution
Adaptations to surroundings

30. Darwin Descent with modification
“ through time species accumulate differences;
As a result:
When new species are formed
Descendent species differ from its ancestor”

31. Descent with Modification
All organisms are related
Descent from an ancestor that lived awhile ago
Descendants were in various habitats
Diverse modifications or adaptations
Specific ways of life

32. Descent with Modification
History of life as a tree
Trunk is the common ancestor
Branches represent an ancestor of all the lines that evolve from that point
Recent divergence--closely related species
Many branches dead end
Many species are extinct

33. Fig. 22-8 Millions of years ago Years ago Hyracoidea (Hyraxes) Sirenia
(Manatees
and relatives)
Moeritherium
Barytherium
Deinotherium
Mammut
Platybelodon
Stegodon
Mammuthus
Elephas maximus
(Asia)
Loxodonta
africana
(Africa)
Loxodonta cyclotis
(Africa) 34 24
5.5 2
104
Millions of years ago
Years ago

34. Artificial selection Modification of crops
Modification of animals for desired trait
Domesticated foxes
Choosing most docile in the offspring
Mating them
Over time produced a fox very similar to domesticated dogs

35. Variation Variation in the population
Leads to differences in individuals in survival & reproduction
Variation among individuals must be genetically transmitted

36. Fig

37. Natural Selection Mechanism for evolution
Organisms with specific heritable traits
Produce more offspring with the traits
Population grows with more offspring with advantageous traits

38. Natural selection Populations evolve not individuals
Affects inheritable traits
Environment greatly influences selection of traits
Trait favorable in one environment
Detrimental in another
Change in environment causes change in adaptation

39. Evolution Evidence 1. Direct Observations 2. Paleontology 3. Homology
Anatomy
Embryology
Molecular biology
4. Biogeography

40. 1. Direct Observations Industrial Melanism Peppered moth
Variation of traits
Increased industrial use caused blackened trees
Favored darker moth
1956 restrictions on pollution
Favored lighter colored moth

41. Industrial Melanism

42. Bacterial antibiotic resistance

43. Annual hospital admissions1
2,750,000
250,000 base pairs
400
2,500,000
350
Chromosome map
of S. aureus clone USA300
500,000
300
250
2,250,000
Key to adaptations
Annual hospital admissions
with MRSA (thousands)
Methicillin resistance
200
Ability to colonize hosts
750,000
150
Increased disease severity
100
2,000,000
Increased gene exchange
(within species) and
toxin production 50
1,000,000
’93
’94
’95
’96
’97
’98
’99
’00
’01
’02
’03
’04
’05
Figure The rise of methicillin-resistant Staphylococcus aureus (MRSA)
1,750,000
Year
1,250,000
1,500,000

44. HIV Drug resistance 3TC drug affects HIV reverse transcriptase
Enzyme makes DNA from RNA genome
Virus DNA inserted into host DNA
3TC Is similar to cytosine
Resistant HIV carry a different reverse transcriptase (enzyme0
Prevents drug from working

45. 2. Fossils Show change over time Fossils of extinct whales
Supports idea whales came from a species that was a land animal
Fossil evidence that birds came from dinosaurs

46. (a) Pakicetus (terrestrial)
Fig
(a) Pakicetus (terrestrial)
(b) Rhodocetus (predominantly aquatic)
Figure The transition to life in the sea
Pelvis and
hind limb
(c) Dorudon (fully aquatic)
Pelvis and
hind limb
(d) Balaena
(recent whale ancestor)

47. 3. Anatomy Homologous structures
Structures with different appearances & function
Derived from a common ancestor
Forelimbs in humans, cats, whale & bats
Show same arrangement of bones but different uses

48. Homologous structures

49. Humerus Radius Ulna Carpals Metacarpals Phalanges Human Cat Whale Bat
Fig
Humerus
Radius
Ulna
Carpals
Metacarpals
Phalanges
Human
Cat
Whale
Bat

50. Embryology Study of early development
Shows evidence of structures that do not develop into adult structures
Tail
Gills/ears and throat

51. Pharyngeal pouches Post-anal tail Chick embryo (LM) Human embryo
Fig
Pharyngeal
pouches
Post-anal
tail
Chick embryo (LM)
Human embryo

52. Vestigial organs Remnants of organs Do not serve any function now
Resemble structures of their ancestors
Appendix in humans
Pelvis/leg bones in snakes

53. Molecular biology DNA RNA Similar in organisms
Organisms that are very different share a common code
Genes have different functions

54. Molecular biology Compare aa sequence for human hemoglobin
Animals closely related to humans
Have a higher percent of similar aa than those not as closely related
Rhesus monkey has 95% identical aa
Frog has 54% identical aa

55. Evolutionary tree Diagram that shows evolutionary relationships
Descent from common ancestor

56. Homologous characteristic
Fig
Branch point
(common ancestor)
Lungfishes 1
Amphibians
Tetrapods 2
Mammals
Tetrapod limbs
Amniotes 3
Lizards
and snakes
Amnion 4
Crocodiles
Homologous
characteristic 5
Ostriches
Birds 6
Feathers
Hawks and
other birds

57. Convergent evolution
Independent development of similar structures in organisms
Not directly related
Found in organisms that live in similar environment
Sugar glider (Australia) (marsupial)
Flying squirrel (Europe) (placental)

58. Sugar glider NORTH AMERICA AUSTRALIA Flying squirrel
Figure Convergent evolution
Flying squirrel

59. Convergent evolution Analogous structures Evolve independently
Not common ancestor
Adapted to similar environments

60. 4. Biogeography Geographic distribution of species
Closely related species live in the same geographic region
Distant regions are occupied by very different species

61. Biogeography Australia Home to marsupials Embryo develops in a pouch
Isolated by geography
Placental mammals
Embryo develops in uterus