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EVOLUTION CHAPTER 15

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Page 1: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

EVOLUTION

CHAPTER 15

Page 2: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• Evolution: the change over time of the genetic composition of populations

• Natural Selection: populations of organisms can change over the generations if individuals having certain heritable traits leave more offspring than others (differential reproductive success)

• Evolutionary Adapations: a prevalence of inherited characteristics that enhance organisms’ survival and reproduction

Page 3: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

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EVOLUTIONARY HISTORY– Linnaeus - taxonomy - Lyell - uniformitarianism

– Hutton - gradualism - Darwin - evolution

– Lamarck - evolution - Mendel - inheritance

– Malthus - populations - Wallace - evolution

– Cuvier - paleontology - Count Buffon - evolution

Page 4: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

RESISTANCE TO THE THEORY OF EVOLUTION

Page 5: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

RESISTANCE TO THE THEORY OF EVOLUTION

Page 6: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

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DARWIN’S INFLUENCES

Taxonomy matured during mid-eighteenth centuryLinnaeus believed in:

He developed the binomial system of nomenclature

System of classification for living things Count Buffon:

Wrote 44-volume catalog of all known plants and animals

Suggested descent with modification

Page 7: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

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Lamarck = First biologist to: Propose evolution Link diversity with environmental adaptation

Concluded more complex organisms are descended from less complex organisms: SIMPLE TO COMPLEX

Proposed inheritance of acquired characteristics – Lamarckianism

DARWIN’S INFLUENCES

Page 8: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Passing on Acquired Traits

Page 9: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

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DESIRE TO CHANGE

Page 10: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Use and Disuse

Page 11: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

HMS BEAGLE VOYAGE• Invited to travel around the

world– 1831-1836 (22 years old!)– makes many observations of

nature• main mission of the Beagle was to

chart South American coastline

Page 12: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• While on the voyage of the HMS Beagle in the 1830s, Charles Darwin observed– similarities between living and fossil

organisms

– the diversity of life on the Galápagos Islands, such as blue-footed boobies and giant tortoises

Figure 13.1A

Page 13: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

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FINCHES

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Page 14: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

MALTHUSOverpopulation and

species control

LYELLEarth is subject to slow but continuous cycles of erosion

Proposed uniformitarianism, rates and processes of change are constant

DARWIN’S INFLUENCES

Page 15: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• Darwin became convinced that the Earth was old and continually changing– He concluded that living things also

change, or evolve over generations

– He also stated that living species descended from earlier life-forms: descent with modification (originally Buffon and Erasmus Darwin)

• All organisms are related through decent from an ancestor that lived in the remote past.

Page 16: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

1. Population has Variation2. Variations may be favorable3. More offspring are produced than survive4. Survivors have favorable traits5. Populations change over time

DARWIN’S 5 MAJOR CONCLUSIONS

Page 17: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

ON THE ORIGIN OF SPECIES

• ......ALL THIS LEADS TO HIS THEORY OF NATURAL SELECTION and SURVIVAL OF THE FITTEST

• 1859 Publication

• Wallace influence

Page 18: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Early 19th century

IndustrialRevolution

WITNESSING NATURAL SELECTION

Page 19: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change
Page 20: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Evolution evidence: Fossils

Page 21: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• The fossil record shows that organisms have appeared in a historical sequence

• Many fossils link early extinct species with species living today

– These fossilized hind leg bones link living whales with their land-dwelling ancestors

Figure 13.2G, H

Page 22: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

2006 Fossil Discovery of Early Tetrapod

• Tiktaalik– “missing link” from sea to land

animals

Page 23: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• Similar structure

• Similar development

• Different functions

• Evidence of close evolutionary relationship– recent

common ancestor

Evolution evidence: Homologous Structures

Page 24: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

spines

tendrilssucculent leaves

colored leaves

Homologous structures

leaves

needles

Page 25: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Evolution evidence: Analogous Structures

Separate evolution of structures

similar functions similar external

form different internal

structure & development

different origin no evolutionary

relationship

Don’t be fooledby their looks!

Page 26: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Evolution evidence: Comparative

Embryology

Page 27: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• Modern animals may have structures that serve little or no function– remnants of structures that were functional

in ancestral species– deleterious mutations accumulate in genes

for non-critical structures without reducing fitness

• snakes & whales — remains of pelvis & leg bones of walking ancestors

• eyes on blind cave fish

• human tail bone

Evolution evidence: Vestigial Structures

Page 28: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Evolution evidence: Molecular Biology

• Similarities in DNA, proteins, genes, and gene products

• Common genetic code

Closely related species have sequences that are more similar than distantly related species

DNA & proteins are a molecular record of evolutionary relationships

Page 29: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

Fig. 22-20

• Darwin’s observations of biogeography, the geographic distribution of species, formed an important part of his theory of evolution

• Islands have many endemic species that are often closely related to species on the mainland

Evolution evidence: Biogeography

Page 30: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• Insecticide & drug resistance

–insecticide didn’t kill all individuals

–resistant survivors reproduce

–resistance is inherited

–insecticide becomes less & less effective

NATURAL SELECTION IN ACTION

Page 31: EVOLUTION CHAPTER 15. Evolution: the change over time of the genetic composition of populations Natural Selection: populations of organisms can change

• Artificial breeding can use variations in populations to create vastly different “breeds” & “varieties”

““descendantsdescendants”” of the wolf of the wolf

““descendantsdescendants”” of wild mustard of wild mustard

ARTIFICIAL SELECTION