Evolution Chapters 21-24

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Evolution Chapters 21-24
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Evolution (chapter 22)

• Change over time in the genetic composition of a
  population
• Descent with modification

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Evolution History
Linnaeus (classification)
Hutton (gradual geologic change)
Lamarck (species can change)
Malthus (population limits)
Cuvier (fossils, extinction)
Lyell (modern geology)
Darwin (evolution, natural selection)
Wallace (evolution, natural selection)
American Revolution
French Revolution
U.S. Civil War
1900
1850
1800
1750
1795
Hutton proposes his theory of gradualism.
1798
Malthus publishes Essay on the Principle of
Population.
1809
Lamarck publishes his hypothesis of evolution.
1830
Lyell publishes Principles of Geology.
18311836
Darwin travels around the world on HMS Beagle.
1837
1837
Darwin begins his notebooks.
1844
Darwin writes essay on descent with modification.
1858
Wallace sends his hypothesis to Darwin.
1859
The Origin of Species is published.
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Evolution History

• Aristotle
• Scala naturae
• Each form of life was permanent

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Linnaeus

• Taxonomy
• Naming classifying organisms
• Binomial system (Genus species)
• Grouping similar species in general categories

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Georges Cuvier

• Paleontology
• Study of fossils
• Noted species in some layers of rocks
• Catastrophism
• Events in the past occurred suddenly
• Different from present day
• Each layer in rocks represents a catastrophe

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Hutton

• Gradualism
• Change can take place through cumulative effect
• Slow but continuous processes
• Valleys formed from rivers eroding away rocks
  over time

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Hutton

• Marine fossils had been carried by rivers to the
  sea
• Fossils placed in sedimentary rock

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Lyell

• Uniformitarianism
• Mechanism of change are constant over time
• Geological processes are happening now as they
  were in the past

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Lamacrk

• Two principles
• 1. Use and disuse
• Parts of the body used became stronger
• Those not used deteriorate

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Lamacrk

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

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Charles Darwin
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Darwins voyage
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Darwins voyage
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Darwins voyage
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Darwins voyage
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Darwins 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

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Finches
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Darwins voyage

• Conclusion
• Birds adapted to environment to survive
• Adapted to food source that is available

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Darwin

• Adaptation
• Accumulation of inherited characteristics
• Enhance an organisms ability to survive
• Reproduce in specific environment
• Result of natural selection

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Wallace

• Developed a theory of natural selection similar
  to Darwins
• Forced Darwin to publish his writings

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Charles Darwin

• November 24, 1859 Origin of Species
• Focused on diversity of animals
• Origins relationships
• Similarities differences
• Geographic distribution
• Adaptations to surroundings

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Adaptation
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Adaptation
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Fig. 22-12a
(a) A flower mantid in Malaysia
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Fig. 22-12b
(b) A stick mantid in Africa
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Darwin

• Descent with modification
• through time species accumulate differences
• As a result
• When new species are formed
• Descendent species differ from its ancestor

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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

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Origin of Species

• 1. Present species on earth are decendents of
  ancestral species
• 2. Natural Selection
• Mechanism for evolution
• Organisms with specific heritable traits
• Produce more offspring with the traits
• Population grows with more offspring with
  advantageous traits

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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

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

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Variation

• Variation in the population
• Leads to differences in individuals in survival
  reproduction
• Variation among individuals must be genetically
  transmitted

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Fig. 22-10
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Variation
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Natural selection

• 1. Selects the organism that will survive better
• Reproduce at a high rate
• 2. Selection depends on environment
• Over time, organisms adapt to environment
• 3. Change in environment causes change in
  adaptation
• Can lead to new species

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Natural selection

• 1. Populations evolve not individuals
• 2. Affects inheritable traits
• 3. Environment greatly influences selection of
  traits
• Trait favorable in one environment
• Detrimental in another

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Evolution Evidence

• 1. Direct Observations
• 2. Paleontology
• 3. Homology
• Anatomy
• Embryology
• Molecular biology
• 4. Biogeography

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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

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Industrial Melanism
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Bacterial antibiotic resistance
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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

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Guppies

• Wild
• Dull colors less attractive to predators
• Bright colors more attractive to mates
• Ponds increased predators dull
• Ponds decreased predators brighter

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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

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Fig. 22-16
(a) Pakicetus (terrestrial)
(b) Rhodocetus (predominantly aquatic)
Pelvis and hind limb
(c) Dorudon (fully aquatic)
Pelvis and hind limb
(d) Balaena (recent whale ancestor)
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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

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Homologous structures
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Fig. 22-17
Humerus
Radius
Ulna
Carpals
Metacarpals
Phalanges
Human
Whale
Cat
Bat
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Embryology

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

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Fig. 22-18
Pharyngeal pouches
Post-anal tail
Human embryo
Chick embryo (LM)
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Vestigial organs

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

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Molecular biology

• DNA
• RNA
• Similar in organisms
• Organisms that are very different share a common
  code
• Genes have different functions

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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

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Evolutionary tree

• Diagram that shows evolutionary relationships
• Descent from common ancestor

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Fig. 22-19
Branch point (common ancestor)
Lungfishes
Amphibians
1
Tetrapods
Mammals
2
Tetrapod limbs
Amniotes
Lizards and snakes
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Amnion
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Crocodiles
Homologous characteristic
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Ostriches
Birds
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Feathers
Hawks and other birds
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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)

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Fig. 22-20
NORTH AMERICA
Sugar glider
AUSTRALIA
Flying squirrel
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Convergent evolution

• Analogous structures
• Evolve independently
• Not common ancestor
• Adapted to similar environments

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4. Biogeography

• Geographic distribution of species
• Closely related species live in the same
  geographic region
• Distant regions are occupied by very different
  species

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Biogeography

• Australia
• Home to marsupials
• Embryo develops in a pouch
• Isolated by geography
• Placental mammals
• Embryo develops in uterus