3. Evolution. What do we need to know?
Biological evolution is due to:
(1) genetic variability of offspring due to mutations and genetic recombination,
(2) the potential for a species to increase its numbers,
(3) a finite supply of resources, and
(4) selection by the environment for those offspring better able to survive and produce offspring
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4. Evolution. What do we need to know?
Random changes in the genetic makeup of cells and organisms (mutations) can cause changes in their physical characteristics or behaviors. If the genetic mutations occur in eggs or sperm cells, the changes will be inherited by offspring. While many of these changes will be harmful, a small minority may allow the offspring to better survive and reproduce.
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5. Evolution. What do we need to know?
The great diversity of organisms is the result of more than 3.5 billion years of evolution that has filled available ecosystem niches on Earth with life forms.
The fossil record and anatomical and molecular similarities observed among diverse species of living organisms provide evidence of biological evolution.
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6. Evolution. What do we need to know?
Biological classifications are based on how organisms are related, reflecting their evolutionary history. Scientists infer relationships from physiological traits, genetic information, and the ability of two organisms to produce fertile offspring
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7. © 2011 Pearson Education, Inc
Concept 22.1: The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species
Darwin’s ideas had deep biblical and historical roots
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Modified Adams 2017.

8. Scala Naturae and Classification of Species
The Old Testament holds that species were individually designed by God and therefore perfect
 scala naturae (“scale of nature”). Categorized all organisms in order of “perfection.”
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Modified Adams 2017.

9. Linnaeus and Adaptations
interpreted adaptations as evidence that God had designed each species for a specific purpose
Linnaeus was the founder of taxonomy, the branch of biology concerned with classifying organisms
He developed the binomial format for naming species (for example, Homo sapiens)
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Modified Adams 2017. .

10. Ideas About Change over Time
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11. © 2011 Pearson Education, Inc
Paleontology, the study of fossils, was largely developed by French scientist Georges Cuvier
Cuvier advocated catastrophism, speculating that each boundary between strata represents a catastrophe
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© 2011 Pearson Education, Inc.

12. James Hutton and Charles Lyell
Geologists (Earth was more than 6000 years old) perceived that changes in Earth’s surface can result from slow continuous actions still operating today
Lyell’s principle of uniformitarianism states that the mechanisms of change are constant over time
This view strongly influenced Darwin’s thinking
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© 2011 Pearson Education, Inc.

13. © 2011 Pearson Education, Inc
Cuvier
Developed the concept of Paleontology, the study of fossils
Cuvier promoted catastrophism, speculating that each boundary between strata represents a catastrophe
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Modified Adams 2017.

14. Ken Carpenter’s Dino Dig
Camarasaurus
Casting for transport to the Denver History Museum
Rib bone and Vertebrae
Allosaurus
Group Shot
The “Paleontology Shot”

15. © 2011 Pearson Education, Inc
Cuvier
Catastrophism, speculating that each boundary between strata represents a catastrophe
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Modified Adams 2017.

16. © 2011 Pearson Education, Inc

17. Ideas About Change over Time
Sedimentary rock
layers (strata)
Figure 22.3 Formation of sedimentary strata with fossils.
Younger stratum
with more recent
fossils
Older stratum
with older fossils
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18. Lamarck’s Hypothesis of Evolution
Lamarck hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics
The mechanisms he proposed are unsupported by evidence
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© 2011 Pearson Education, Inc.

19. © 2011 Pearson Education, Inc
Concept 22.2: Descent with modification by natural selection explains the adaptations of organisms and the unity and diversity of life
Descent with modification is simply passing traits from parent to offspring, and this concept is one of the fundamental ideas behind Charles Darwin's theory of evolution. ... You pass traits on to your children in a process known as heredity. The unit of heredity is the gene.
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© 2011 Pearson Education, Inc.

20. Acquired traits cannot be inherited.
Figure 22.4 Acquired traits cannot be inherited.
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21. © 2011 Pearson Education, Inc
Figure 22.5
The voyage of HMS Beagle.
Darwin in 1840, after his return from the voyage
HMS Beagle in port
Great
Britain
EUROPE
NORTH
AMERICA
ATLANTIC
OCEAN
The
Galápagos
Islands
AFRICA
PACIFIC
OCEAN
Pinta
Genovesa
Equator
Marchena
Malay Archipelago
Equator
SOUTH
AMERICA
PACIFIC
OCEAN
Santiago
Daphne
Islands
Chile
Brazil
AUSTRALIA
Fernandina
Pinzón
PACIFIC
OCEAN
Andes Mtns.
Figure 22.5 The voyage of HMS Beagle.
Isabela
Santa
Cruz
Cape of
Good Hope
Santa Fe
San
Cristobal
Argentina
Tasmania 20 40
Florenza
Española
Cape Horn
Kilometers
New
Zealand
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22. Darwin saw organisms adapted to their environment
(a) Cactus-eater
(b) Insect-eater
Three examples of beak variation in Galápagos finches
Figure 22.6 Three examples of beak variation in Galápagos finches.
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(c) Seed-eater

23. Overview: That “Mystery of Mysteries”
In the Galápagos Islands Darwin discovered plants and animals found nowhere else on Earth
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24. Figure 24.1
How did this flightless bird come to live on the isolated Galápagos Islands?
Figure 24.1 How did this flightless bird come to live on the isolated Galápagos Islands?

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In 1844, Darwin wrote an essay on natural selection as the mechanism of descent with modification, but did not introduce his theory publicly
Natural selection is a process in which individuals with favorable inherited traits are more likely to survive and reproduce
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© 2011 Pearson Education, Inc.

26. © 2011 Pearson Education, Inc
The Origin of Species
Darwin explained three broad observations:
The unity of life
The diversity of life
The match between organisms and their environment
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© 2011 Pearson Education, Inc.

27. © 2011 Pearson Education, Inc
The gist:
Darwin noted that current species are descendants of ancestral species
Evolution can be defined by Darwin’s phrase descent with modification
(refers to the view that all organisms are related through descent from an ancestor that lived in the remote past)
Evolution can be viewed as both a pattern and a process
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© 2011 Pearson Education, Inc.

28. © 2011 Pearson Education, Inc
In the Darwinian view, the history of life is like a tree with branches representing life’s diversity
Darwin’s theory meshed well with the hierarchy of Linnaeus
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© 2011 Pearson Education, Inc.

29. Descent with modification
Hyracoidea
(Hyraxes)
Sirenia
(Manatees
and relatives)
†Moeritherium
†Barytherium
†Deinotherium
†Mammut
†Platybelodon
†Stegodon
†Mammuthus
Figure 22.8 Descent with modification.
Elephas maximus
(Asia)
Loxodonta africana
(Africa)
Loxodonta cyclotis
(Africa) 60 34 24
5.5 2
104
Millions of years ago
Years ago
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30. Now, Darwin has to make an argument…
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31. Here are some common observations and inferences:
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32. © 2011 Pearson Education, Inc
Descent with modification came from a couple particular observations and inferences:
Observation #1: Members of a population often vary in their inherited traits
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© 2011 Pearson Education, Inc.

33. © 2011 Pearson Education, Inc
Inference #1: Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment will produce more offspring than other individuals
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Modified Adams 2017.

34. © 2011 Pearson Education, Inc
Observation #2: All species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce
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© 2011 Pearson Education, Inc.

35. © 2011 Pearson Education, Inc
Inference #2: This imbalance of individuals to survive and reproduce leads to the accumulation of favorable traits in the population over generations
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Modified Adams 2017.

36. © 2011 Pearson Education, Inc
What happens at intersection?
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37. © 2011 Pearson Education, Inc
An example of adaptation: Camouflage as an example of evolutionary adaptation
Figure Camouflage as an example of evolutionary adaptation.
(a) ?
(b) ?
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38. © 2011 Pearson Education, Inc
An example of adaptation: Camouflage as an example of evolutionary adaptation
Figure Camouflage as an example of evolutionary adaptation.
(a) A flower mantid in Malaysia
(b) A leaf mantid in Borneo
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39. © 2011 Pearson Education, Inc
Note: that individuals do not evolve; populations evolve over time
Note: Natural selection can only increase or decrease passed traits that already exist and vary in a population
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© 2011 Pearson Education, Inc.

40. © 2011 Pearson Education, Inc
Concept 22.3: Evolution is supported by an overwhelming amount of scientific evidence
Evidence continues to fill the gaps identified by Darwin in The Origin of Species
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© 2011 Pearson Education, Inc.

41. Evidence type 1: Direct Observations of Evolutionary Change
Two examples provide evidence for natural selection: natural selection in response to introduced plant species, and the evolution of drug-resistant bacteria
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© 2011 Pearson Education, Inc.

42. © 2011 Pearson Education, Inc
Figure 22.13a
Can a change in a population’s food source result in evolution by natural selection?
FIELD STUDY
Figure Inquiry: Can a change in a population’s food source result in evolution by natural selection?
Soapberry bug with beak inserted in balloon vine fruit
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43. © 2011 Pearson Education, Inc
Can a change in a population’s food source result in evolution by natural selection?
RESULTS
Beak 10
On native species, southern Florida 8 6 4 2
Number of individuals
Museum-specimen average 10 8
On introduced species, central Florida
Figure Inquiry: Can a change in a population’s food source result in evolution by natural selection? 6 4 2 6 7 8 9 10 11
Beak length (mm)
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44. The Evolution of Drug-Resistant Bacteria
The bacterium Staphylococcus aureus is commonly found on people
One strain, methicillin-resistant S. aureus (MRSA) is a dangerous pathogen
S. aureus became resistant to penicillin in 1945, two years after it was first widely used
S. aureus became resistant to methicillin in 1961, two years after it was first widely used
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45. © 2011 Pearson Education, Inc
Methicillin works by inhibiting a protein used by bacteria in their cell walls
MRSA bacteria use a different protein in their cell walls
When exposed to methicillin, MRSA strains are more likely to survive and reproduce than nonresistant S. aureus strains
MRSA strains are now resistant to many antibiotics
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© 2011 Pearson Education, Inc.

46. Chromosome map of S. aureus clone USA300
Figure 22.14 1
2,750,000
250,000 base pairs
2,500,000
Chromosome map of S. aureus clone USA300
500,000
2,250,000
Key to adaptations
Methicillin resistance
Ability to colonize hosts
750,000
Increased disease severity
2,000,000
Increased gene exchange (within species) and toxin production
Figure Impact: The Rise of MRSA
1,000,000
1,750,000
1,250,000
1,500,000
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47. Evidence type 2: Homology
Homology is similarity resulting from common ancestry
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© 2011 Pearson Education, Inc.

48. Anatomical and Molecular Homologies
Homologous structures are anatomical resemblances that represent variations on a structural theme present in a common ancestor
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© 2011 Pearson Education, Inc.

49. © 2011 Pearson Education, Inc
Figure 22.15
Humerus
Radius
Ulna
Carpals
Metacarpals
Figure Mammalian forelimbs: homologous structures.
Phalanges
Human
Cat
Whale
Bat
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50. © 2011 Pearson Education, Inc
Figure 22.16
Comparative embryology reveals anatomical homologies not visible in adult organisms
Pharyngeal pouches
Post-anal tail
Figure Anatomical similarities in vertebrate embryos.
Chick embryo (LM)
Human embryo
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51. © 2011 Pearson Education, Inc
Vestigial structures and genes
have no apparent function and appear to be residual parts from a past ancestor
Examples: human appendix, the pelvic bone of a snake, and the wings of flightless birds.
Can become disadvantageous, but in most cases these structures are harmless; however, these structures, like any other structure, require extra energy and are at risk for disease.
Vestigial structures, especially non-harmful ones, take a long time to be phased out since eliminating them would require major alterations that could result in negative side effects.
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Modified Adams 2017

52. Tree thinking: hypotheses of evolutionary relationships.
Branch point
Lungfishes
Amphibians 1
Tetrapods 2
Mammals
Digit- bearing
limbs
Amniotes 3
Lizards and snakes
Amnion 4
Crocodiles
Homologous characteristic
Figure Tree thinking: information provided in an evolutionary tree. 5
Ostriches 6
Birds
Feathers
Hawks and other birds
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53. Evidence type 3. The Fossil Record
The fossil record provides evidence of the extinction of species, the origin of new groups, and changes within groups over time
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© 2011 Pearson Education, Inc.

54. © 2011 Pearson Education, Inc
Figure 22.19
Most mammals
Cetaceans and even-toed ungulates
Figure Ankle bones: one piece of the puzzle.
(a) Canis (dog)
(b) Pakicetus
(c) Sus (pig)
(d) Odocoileus (deer)
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55. © 2011 Pearson Education, Inc
Figure 22.UN01
Figure 22.UN01 In-text figure, p. 465
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56. © 2011 Pearson Education, Inc
Other even-toed ungulates
Hippopotamuses
†Pakicetus
†Rodhocetus
Common ancestor of cetaceans
†Dorudon
Figure The transition to life in the sea.
Living cetaceans 70 60 50 40 30 20 10
Key
Pelvis
Tibia
Millions of years ago
Femur
Foot
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57. Evidence type 4. Biogeography
Biogeography, the geographic distribution of species, provides evidence of evolution
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© 2011 Pearson Education, Inc.

58. Speciation, the origin of new species, is at the focal point of evolutionary theory
Evolutionary theory must explain how new species originate and how populations evolve
Microevolution consists of changes in allele frequency in a population over time
Macroevolution refers to broad patterns of evolutionary change above the species level
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59. Animation: Macroevolution Right-click slide / select “Play”
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