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Biology 2900 Principles of Evolution and Systematics

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Title: Biology 2900 Principles of Evolution and Systematics


1
Biology 2900Principles of Evolutionand
Systematics
  • Dr. David Innes
  • Jennifer Gosse
  • Valerie Power

2
  • Lecture Tues. Thurs 1030 - 1145 am
  • IIC-2001
  • Laboratory Mon Tues Wed Thr 200 - 500 pm
  • SN-4110
  • Labs. Week of January 7 11
  • Organization of groups
  • Group 1 Lab. Week of Jan. 14
  • Download handout
  • http//www.mun.ca/biology/dinnes/B2900/B29
    00.html

3
Course Web Site
  • http//www.mun.ca/biology/dinnes/B2900/B2900.htm
    l
  • Course outline
  • Lecture slides (pdf file)
  • Lab. Information (new Lab. 1)
  • Information, readings etc.
  • Links to Evolution Web Page
  • Midterm Test Thursday, Feb. 14, 2008

4
Desire2Learn
  • https//online.mun.ca/
  • Login using MUN account
  • 1. Course outline
  • 2. Surveys i) student information
  • ii) anonymous feedback
  • 3. Internal email
  • 4. online quizzes

5
Goals
  • Ask interesting questions about evolution
  • Experiments and observations to answer ??
  • Critically evaluate primary literature
  • Contribute to the discussion of evolution between
    specialists and public
  • Think like evolutionary biologists !!!!

6
Evolution Thinking
  • Why do organisms age and die ?
  • What do fossils tell us about the evolutionary
    history of plants and animals?
  • Why do some male spider sacrifice themselves
    during mating?

7
Example
Sex and death in the Australian red-back spider
Sexual cannibalism How could
evolution have produced a behavior that reduces
the chance of survival ? (Research of
Dr. Andrade, U. of T.)
male
male
8
Experimental Results
  • Cannibalized males copulated longer and
    fertilized more eggs than those that survived
    copulation
  • Females were more likely to reject subsequent
    suitors after consuming their first mate
  • Empirical evidence for male copulatory
  • suicide as an adaptive behavior

9
Chapter 6 How to make love to a cannibal
Olivia Judson
10
  • Evolution
  • a change in the properties of groups of
    organisms over the course of generations (ie.
    time) (Futuyma, 2005)

11
  • current life forms differ from those of previous
    times and yet are descended from them
  • Descent with modification

12
  • The study of Evolution
  • - how populations change in response to their
    environment
  • - formation of new species
  • The Study of Adaptation and Diversity

13
  • The Fact of Evolution
  • - evidence from biology and geology
  • - species have changed through time
  • - descended with modification from common
    ancestors

14
  • The Fact of Evolution
  • Evidence
  • 1. relatedness of life forms
  • 2. change through time
  • 3. age of the earth

15
  • Relatedness of life forms

Morphology homology (vert. limb
bones) Molecular conserved structure and function
Cytochrome c Cellular respiration 3D structure
based on amino acid sequence
Tuna fish
Rice
16
Darwin
  • One of the most revolutionary ideas in the
    history of science
  • All organic beings which
  • have ever lived on this earth
  • have descended from some
  • one primordial form

17
The Fact of Evolution
  • A scientific theory is a mature, coherent body
    of interconnected statements, based on reasoning
    and evidence, that explains a variety of
    observations
  • The fact of evolution is explained by
    evolutionary theory

Futuyma, 2005
18
  • The study of Evolution
  • (Adaptation and Diversity)
  • Where do living things come from ?
  • Why are there so many different kinds of
    organisms ?
  • How have organisms adapted so well to their
    environment ?

19
  • Darwin (Origin of Species)
  • Existing species are the modified descendants of
    forms that existed previously
  • (descended from common ancestors)
  • But how ? ?Natural Selection
  • Theory by C. R. Darwin and A. R. Wallace

20
Artificial Selection
  • The mechanism of evolution under domestication
  • 1. Phenotypic Variation
  • 2. Variation heritable
  • 3. Selective breeding (non-random
  • survival and reproduction)

C. Darwin (1868) The variation of animals and
plants under domestication
21
C. Darwin (1883) The variation of animals and
plants under
domestication
http//www.esp.org/books/darwin/variation/facsimil
e/title3.html
22
Dogs
23
Domestic Cats
24
Pigeons
25
Cabbage
Brassica oleracea
Wild Cabbage
Kale
26
Natural Selection
  • Darwin realized that a process much like
  • artificial selection happens in
    nature
  • Why did it take so long to realize a connection
    between the power of artificial selection and the
    potential of natural selection for evolution?

27
Phenotypic Variation in Natural Populations
  • Phenotypic Variation among individuals within a
    wild species much more subtle

28
Phenotypic Variation in Natural Populations
29
Natural Selection
  • The Theory of Evolution by Natural Selection
  • Evolution is the logical outcome of 4 postulates

30
Evolution by Natural Selection
  • 1. Individuals within populations variable (Lab
    1)
  • 2. Some variations inherited by offspring
  • 3. Some individuals more successful at surviving
    and reproducing than others
  • 4. Survival and reproduction not random tied to
    the variation among individuals

31
  • Individuals within populations variable
  • - observed phenotypic variation
  • 2. Some variations inherited by offspring
  • - offspring resemble parents
    (mechanism?)

Evolution by Natural Selection
32
Evolution by Natural Selection
  • 3. Some individuals more successful at surviving
    and reproducing than others
  • - enormous reproductive potential
  • Aphid ?
    524 billion/yr
  • House fly ?
    191 x 1018 in 5 months
  • Thomas Malthus' Essays on
    Population
  • http//personal.clt.bellsouth.net/t/a/tarab
    yl/malthus.htm

33
Evolution by Natural Selection
  • 4. Survival and reproduction not random tied to
    the variation among individuals

Two phenotypes white, yellow
34
Natural Selection
  • If the 4 postulates true, then the composition of
    the population changes from one generation to the
    next
  • Natural Selection produces decent with
    modification (Evolution)

35
  • Fitness
  • Ability of an individual to survive and reproduce
    in its environment
  • Adaptation
  • Traits that increase fitness relative to
    individuals without the traits

36
Adaptation
  • PBS Webpage
  • http//www.pbs.org/wgbh/evolution/library/01/index
    .html

Praying Mantis
Praying Mantis leaf mimic
37
  • Implications and consequences of NS
  • -natural mechanism for evolution
  • -descent from common ancestor ? order
  • -natural classification ? hierarchical
  • -all living things related ? phylogeny
  • -humans evolved
  • Darwin-Wallace Theory of NS testable

38
  • Can natural selection lead to evolutionary change
    ?
  • Model systems to test natural selection
  • Galapagos Finches - P. R. Grant

39
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40
Galapagos Islands
41
  • Galapagos Finches
  • - 13 closely related species
  • differ in beak morphology
  • Variation associated with food eaten
  • http//www.youtube.com/watch?vv16aG5Ve0q0

42
Geospiza fortis
43
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44
(No Transcript)
45
  • Test of 4 postulates
  • Geospiza fortis on the island of
  • Daphne major
  • 1. Are populations variable ?
  • 2. Variation heritable ?
  • 3. Only some offspring live to reproduce ?
  • 4. Survival and reproduction nonrandom ?

If 1, 2, 3, 4, true ? evolution by natural
selection
46
  • 1. Variation in Bill Depth

47
2. Heritability of Bill Depth
Fig 9.20
Offspring Bill Depth (mm)
1978 1976
VP VG VE H2 VG / VP 0.90
Midparent Bill Depth (mm)
48
Seed abundance
Pop. Size
Large Hard
Seeds
3. Not all individuals survived. 4. Was survival
nonrandom with respect to bill size ?
Small Soft
1977 drought
49
Before drought
After drought (survivors)
4. Survival nonrandom with respect to bill size.
Beak Depth (mm)
50
Natural Selection
  • 1. Large amount of variation in bill depth
    (phenotypic)
  • 2. Much of variation heritable (genetic)
  • 3. Drought resulted in decreased survival
  • (due to change in food resource)
  • - only some individuals survived to
    reproduce
  • 4. Survival and reproduction non-random with
    respect to bill
  • depth (birds with larger bills
    favoured)

Did the population evolve?
51
Natural Selection
  • Did the population
  • evolve?
  • Yes!!!
  • Evolutionary change also evident in
    parent-offspring regression

52
Bill Depth Parent Offspring regression
Fig 9.20
1
1978 1976
Offspring Bill Depth (mm)
Midparent Bill Depth (mm)
53
Natural Selection
  • Large amount of variation in bill depth
    (phenotypic)
  • Much of variation heritable (genetic)
  • Drought resulted in decreased survival and
    reproduction
  • (due to change in food resource)
  • - only some individuals survived and
    reproduced
  • Survival and reproduction non-random with
    respect to bill
  • depth (birds with larger bills
    favoured)

54
Natural Selection
  • Finches with a larger, deeper bill had an
  • advantage (directional selection)
  • Drought resulted in only larger, harder seeds
  • Wet years abundant small, soft seed
  • smaller bills favoured
  • Natural Selection is Dynamic

55
Beak Size
Natural Selection Dynamic 30 years of data
Beak Shape
95 CI for 1973 data
Body Size
56
  • Features of Natural Selection
  • 1. Acts on indiv., consequences in pop.
  • 2. Evolution consists of changes in gene
    frequencies

Gen. 1
Freq.
Gen. 2
Phenotype (ie. Size)
If Heritability 0
If Heritability gt 0
57
  • Features of Natural Selection
  • 3. NS not forward looking
  • 4. NS acts on existing traits
  • 5. NS directed, not random
  • 6. Fitness not circular (Survival of the
    fittest)
  • 7. NS acts on individuals not groups

58
  • Features of Natural Selection
  • Components of fitness
  • - survival
  • - reproduction
  • More offspring produced than can survive
  • (Potential for exponential population growth)

59
Examples of Natural Selection
Fig. 13.3 Soapberry bug
60
Examples of Natural Selection
Fig. 13.3 Soapberry bug
Native host plant
Introduced host plant
61
Natural Selection
  • molecular/morphological change over
  • very short time intervals
  • small changes
  • can small changes over short time
  • intervals lead to larger changes over
  • longer time intervals ?

62
  • Changes
  • Microevolution to Macroevolution
  • Requires very long periods of time

63
  • Age of the Earth
  • - about 4.6 billion years ago
  • - first evidence of life 3.8 billion years ago
  • - over long periods of time, small changes become
    large

Fig. 3.12 60 year corn oil selection experiment
64
  • Origin of New Species?
  • - Physical isolation (dispersal and colonization)
  • - Divergent natural selection (diff.
    environments)
  • Natural selection can explain - adaptation

  • - diversity

65
  • Problems that concerned Darwin
  • 1. Source of variation ? mutation
  • 2. Inheritance ? Mendel
  • 3. Age of the earth ? radioisotopes

66
  • Modern Synthesis
  • Synthesis of variability, inheritance and time
  • 1932 - 1953
  • - botany, systematics, population genetics,
    paleontology

67
Evolution by Natural Selection
  • Complexity in nature
  • - how random changes can lead to order ?
  • - how can complex structures evolve through the
    gradual accumulation of small changes ?

68
  • The Eye
  • Evolution of a Complex Structure
  • - each step had to increase fitness
  • - are there diverse forms of eyes, some more
    complex than others ?

69
Mollusc Eyes
Pigment spot
Pigment cup
abalone
octopus
Marine snail
70
Evolution of the eye
  • http//www.pbs.org/wgbh/evolution/library/01/1/l_0
    11_01.html

71
Evolution by Natural Selection
  • Observed diversity of life
  • Organisms adapted to their environment
  • The fact of evolution
  • NS a mechanism for explaining
  • observations
  • Natural Selection in Humans ?
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