Evolution - PowerPoint PPT Presentation

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Evolution

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Key Points. Heritable characteristics increase or decrease an organisms chance of survival. Evolution is the change of the genetic makeup of a population over time – PowerPoint PPT presentation

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Title: Evolution


1
Evolution
2
Key Points
  • Heritable characteristics increase or decrease an
    organisms chance of survival
  • Evolution is the change of the genetic makeup of
    a population over time
  • More closely related organisms have more closely
    related DNA and proteins
  • Many organisms have similar structures, and many
    organisms develop similarly

3
Key Points
  • Mutations that lead to evolution occur randomly
  • All species on earth are related by a common
    ancestor
  • The fossil record shows organisms that are no
    longer alive
  • Environmental pressures, genetic drift, mutation
    and competition for resources lead to evolution

4
How did life on earth begin?
  • There are many theories
  • Information about early earth comes from rocks
  • The earth is 4.6 billion years old
  • The oldest clues about life on earth are 3.5
    billion years old

5
Fossils
  • Fossils are preserved evidence of organisms
  • 99.9 of all organisms are extinct
  • Very few organisms become fossilized
  • Many fossils are casts
  • Minerals fill in the areas where the organism was

6
Dating Methods
  • Relative Dating
  • A technique where items (rocks or fossils) are
    dated by comparing the soil layers
  • The Law of Superposition
  • Sedimentary rock is deposited in layers
  • Older layers are deeper
  • Newer layers are on top
  • Explain the picture?

7
Dating Methods
  • Radiometric Dating
  • Uses radioactive isotopes to date rocks or
    organic material
  • Uses the half life of the isotope
  • Carbon-14
  • Decays to Nitrogen-14
  • Half life is 5730 years
  • Can date organisms up to 50,000 years
  • Potassium-40
  • Used to date older items
  • Can only be used to date rocks
  • Half life is 1.3 Billion years

8
Geologic Time
  • Represents major geologic events

9
Spontaneous Generation-A Hypothesis
  • Spontaneous generation- life arises from no life
  • Francisco Redis experiment
  • Redis experiment opposes the hypothesis

10
Biogenesis- a theory
  • Biogenesis- life arises from life
  • Louis Pasteur biogenesis is true for
    microorganisms

11
Origins of Life
  • Simple organic molecule formation
  • Organic molecules could be synthesized by simple
    reactions
  • UV light from the Sun and lightning may have been
    the primary energy source

Shark Bay, Australia
12
Miller and Urey
  • Simple organic molecules are made from inorganic
    molecules
  • Conditions were like that of early earth

13
Cell Evolution
  • Prokaryotes evolved first
  • Archea most closely resemble earths first life
  • They are autotrophs, energy does not come from
    the sun, they do not need oxygen
  • Photosynthesizing prokaryotes evolved next
  • Oxygen was just a byproduct
  • Eukaryotes evolved by prokaryotes developing
    symbiotic relationships

14
Endosymbiont Theory
15
STOP
  • You are a Paleontologist Activity

16
Brontosaurus
  • Old

New
17
Natural Selection
18
Darwin Natural Selection
  • Darwin was a naturalist on the HMS Beagle
  • He was also a companion to the captain
  • He collected biological samples
  • Darwin collected many birds, mockingbirds and
    finches on the Galapagos Islands
  • Each island had similar birds, but they were
    slightly different

19
Example of Adaptive Radiation
20
Beaks specific for diet
21
Artificial Selection and Natural Selection
  • Humans could changes species (such as dogs) by
    artificial selection
  • Darwins Hypothesis
  • New species could appear gradually through small
    changes in ancestral species
  • Support

22
Natural Selection
  • Individuals in a population show variation
  • Variations are inherited
  • Organisms have more offspring than can survive on
    the available resources
  • Variations that increase reproductive success
    will have a greater chance of being passed on

23
  • Convergent evolution
  • Divergent evolution

24
Support for Evolution
  • Fossils
  • Fossils show species that lived long ago
  • Ancient species share similarities with living
    species

Glyptodont
Armadillo
25
Support for Evolution
  • Derived traits newly evolved features that do
    not appear in common ancestors
  • Feathers
  • Ancestral traits
  • More primitive features that do appear in
    ancestral forms

26
Homologous Structures
  • Anatomically similar structures inherited from a
    common ancestor
  • Structures are used for different purposes

27
Vestigial Structures
  • Structures that are reduced in form
  • They are useful in related organisms
  • Features of ancestors that are no longer useful
    will become smaller or lost over time

28
Analogous Structures
  • Structures used for the same purpose but are not
    from a common ancestor

29
Comparative Embryology
  • Vertebrate embryos look very similar as embryos
  • Develop differently as they get older

30
More Comparative Embryology
31
Comparative Biochemistry
  • Common ancestry can be seen in metabolic
    molecules
  • DNA
  • Amino acid sequences
  • More closely related organisms have similar
    sequences

32
How Organisms Evolve
33
Blue Skinned PeopleThe Fugate Family
  • Affects an entire family from isolated Appalachia
    (Kentucky)
  • Skin tinged blue ? almost purple
  • Recessive diseases ? Methemoglobinemia
  • Blood disorder in which an abnormal amount of
    methemoglobin -- a form of hemoglobin
  • Hemoglobin - responsible for distributing oxygen
    to the body
  • Family had a deficiency in the enzyme called
    cytochrome-b5 methemoglobin reductase
  • blue hemoglobin never converted to red
    hemoglobin
  • No side health effects
  • Many Futates lived into their 80s and 90s.

Martin Fugate came to Troublesome Creek from
France in 1820 and family folklore says he was
blue. His wife carried the recessive gene. Of
their seven children, four were reported to be
blue
34
Genetic Drift
  • Change in allele frequency
  • Caused by chance
  • Seen in small populations

35
  • Founder Effect
  • Population Bottleneck
  • A small sample of a population emigrate to a new
    area
  • Alleles that were uncommon in the parent
    population become popular
  • The population almost goes extinct
  • A few surviving members survive and reproduce

36
Gene Flow
Nonrandom Mating
  • Immigration and emigration
  • Increases variation within a population
  • Promotes inbreeding
  • Can cause alleles frequency to change
  • Female is usually choosey
  • Male usually displays traits

37
Types of Selection
  • The best suited individuals survive
  • Derive a situation that could cause each graph.

38
Human Evolution
39
Human Evolution
  • What is a primate (Ape)
  • Manual dexterity
  • Flexible bodies
  • Limber shoulders and hips
  • Large Brain
  • Can solve problems
  • Social
  • Newborns dependent on mother
  • Have fewer offspring
  • Are you an ape?

40
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41
Humans
  • Bipedalism- changing environment
  • Large Brain- evolved after bipedalism

42
Primate/human Tree
43
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44
So, are we an ape?
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