Biology 2900 Principles of Evolution and Systematics

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Biology 2900Principles of Evolutionand
Systematics

• Dr. David Innes
• Dr. Ted Miller
• Jennifer Gosse
• Valerie Power

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Announcements
Sir Joseph Banks (1743-1820) Sir Joseph
Banks inherited his fathers estates in
Lincolnshire and considerable wealth in 1761. His
first voyage of discovery was to the coasts of
Newfoundland and Labrador on HMS Niger, and on
his return to London in 1767, he was elected a
member of the Royal Society at the age of just
23. Banks was involved in most British
voyages of discovery of his day, including the
Bounty voyage under William Bligh, 1787-1789,
Blighs later voyage in HMS Providence, and
Matthew Flinderss circumnavigation of Australia,
1800-1805. He also organised the introduction of
the first sheep into Australia.
Happy Birthday (Feb. 12, 1809)
Happy Birthday (Feb. 13, 1743)
Every blockhead does that My grand tour shall
be one round the whole globe (Joseph Banks in
response to his familys suggestion that he
undertake the traditional Grand Tour of Italy and
the sites of classical antiquity). And it
was. Joseph Banks (17431820), one of the richest
characters, most multi-talented and indefatigable
of 18th century individuals (later President of
the Royal Society for 41 years) joined Captain
Cook on HMS Endeavours first journey (1768).
When the voyage set out, Banks was only 25.
Samuel Johnson, remarked of the 106 foot
Endeavour that, rather than sail on her, he would
have turned, with relief, to jail.
Banksia
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Announcements

• Lab 3 (Group 1) handout ? print from course web
  page
• http//www.mun.ca/biology/dinnes/B2900/B2900.html
• Midterm Test Thursday Feb. 15

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Announcements

• Chapter References (Futuyma, 2004)
• Ch. 1. Evolutionary Biology p. 1 14
• Ch. 3. Patterns of Evolution Box 3A p. 48 49
• Ch. 9 Variation p. 189 222
• Ch. 10 Genetic Drift p. 225 235 241 242
• Ch. 11 Natural Selection and Adaptation p. 247
  255
• Ch. 12 The Genetical Theory of Natural Selection
  p. 269 285 293 294
• Ch. 13 Evolution of Phenotypic Traits p. 297
  301 304 310 317 319
• Ch. 17 How to be fit Reproductive Success p. p.
  417 - 422

Midterm Test Thursday Feb. 15
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Announcements
Midterm Test Thursday Feb. 15

• Format
• A. True / False
• B. Short Answer
• C. Matching terms
• D. Problem
• Read and interpret graphs,
  draw graphs
• Example Test
• http//www.mun.ca/biology/dinnes/B2900/Midterm00.h
  tml

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Principles of Evolution and Systematics

• Darwin Natural selection (Galapagos Finches )
• Population Quantitative genetics (Genes in
  populations)
• Natural selection Adaptation (Form and
  function)
• Adaptation and Diversity
• (part I part II)

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Studies in Evolution

• Reproductive success
• Sex and Sexual Selection

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• Reproduction
• Reproduction an important adaptation
• A diversity of modes of reproduction

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Variation in Reproduction

• Separate sexes - dioecious (plants)
• - gonochoristic
  (animals)
• Co-sexual hermaphroditic
• (malefemale)
• Asexual

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Sexual Selection

• Chapter 14

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Sexual Dimorphism

• Males and females often differ in size,
  appearance and behavior

?
?
Whats he on about ?
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Male and female height dimorphism in 200 human
societies
In addition, Secondary sex characteristics
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Adaptive significance of sexual dimorphism??

• Sexual dimorphism difficult to
• explain by natural selection
• Example long tail feathers
• How can the evolution of sexual dimorphism be
  explained?

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Darwin and sexual dimorphism

• Challenges for passing on ones genes
• 1. Surviving
• 2. Reproducing
• And for sexual reproduction
• 3. Finding and mating with
  a
• member of the opposite
  sex

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Sexual Selection

• Differences among individuals at getting mates
• i.e. Mating success

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Sexual Selection

• Asymmetry
• - eggs are more expensive than ejaculates
• (eggs yolky sperm DNA propeller)
• - parental care by females, none by
• males (90 of mammal species)

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Sexual Selection

• Asymmetry
• Females
  Males
• Limits to of eggs of
• reproductive produced matings
• success

Access to females a limiting resource for males
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Batemans Experiment

• Test of asymmetric reproductive success
• D. melanogaster 3 virgin males
• 3 virgin females
• (each individual had 3 potential mates)
• Measured
• 1. number of actual mates
• 2. reproductive success ( of
  offspring)

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• Results

(a)
(b)
(c)
Variance in reproductive success males gt females
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• Results

Males reproductive success increases with
number of mates great variation
in the number of mates great
variation among males in reproductive
success Females no increase in reproductive
success with gt 1 mate less
variation in number of mates
little variation among females in reproductive
success
Other examples ??
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Rough-skinned newt
males
females

• All females mated
• Most males not mated
• Females number of mates doesnt increase of
  offspring
• Males increased of offspring with of mates

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Consequences of asymmetry (Female parental care)

• Males should be competitive (intrasexual
  selection)
• Females should be choosy (intersexual
  selection)
• Because females commonly invest much more
  per offspring than males

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Sexual Selection

• Male-Male Competition
• 1. Combat
• 2. Sperm competition
• 3. Infanticide
• 4. Alternative mating strategies
• 5. Female Choice
• 6. Run away sexual selection

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• Male-Male competition
• (size matters)
• 1. Combat
• - favours larger body size
• - weaponry
• - armor

Which is the male?
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Male Combat
(Marine Iguana)
Variation in mating success
observer
territories
Largest male
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Male-Male competition

• 2. Sperm competition
• Male mating success not determined by
  copulation but, whether his sperm fertilizes eggs

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Sperm Competition

• Internal fertilization
• If female mates
• with 2 or more males,
• sperm race to the eggs

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Sperm Competition
M F offspring potential fathers

• external fertilization
• Internal fertilization
• - polyandrous species
• - socially monogamous
• species (extra-pair
• copulation)

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Sperm Competition

• Adaptations to increase chances of winning the
  sperm race
• Large ejaculates with many sperm
• prolong copulation
• mate guarding
• copulatory plug

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Sperm Competition

• Med. Fruit fly males
• sperm
• ejaculated
• 1. Private mating 1,379
• 2. With a potential 3,520
• competitor

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Mate Guarding
Male barn swallows
Eggs laid
Female fertile period
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• Sperm Competition
• Other Adaptations
• Damsel flies

Removes sperm from previous mating
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Sperm Storage

• Birds, insects, mammals
• Control of sperm use by female
• - Last male sperm precedence
• - First male sperm precedence
• - Mixing of sperm

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Sperm Mixing(wood louse)

• Female Progeny Genotype
• 2/2 2/3 2/4 2/5
  2/6
• 2/2 2 10 7 21
  1
• Maternal allele 2
• Paternal alleles 2, 3, 4, 5, 6
• Possible male genotypes 2/3, 4/5, x/6
• (sperm from at least 3 males)
• 20 females gt 80 multiple
  paternity

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An Evolutionary History of Sperm Competition T.
R. Birkhead (2000)
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Sperm Competition
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• Male-Male competition
• 3. Infanticide
• Pride basic social group of lions
• Newly mature males move to another pride
• New male kills nursing cubs
• - not his offspring
• - causes females to return to breeding
  earlier

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• Male-Male competition
• 4. Alternative mating strategy

Female
Sneaky males
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• 5. Female Choice
• Males unable to monopolize females
• Males advertise for mates
• Females inspect and choose
• sexual selection leads to elaborate
  courtship displays by males

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• Female Choice
• Example
• Barn Swallows
• Males have longer tail feathers
• Used in courtship display

males
females
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• Experiment
• (Anders MØller)
• Groups (males)
• 1. Shortened tail feathers
• 2. Control I (mock alteration)
• 3. Control II (unaltered)
• 4. Elongated tail feathers

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• Results

Premating period second clutches
of fledglings
Demonstrates females prefer males with longer
tails long-tailed males have high RS
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Extra-pair copulation

• Shortened Control
  Control Lengthened
• tails I
  II tails
• By their
• female 0.036 0.014
  0.017 0.00
• pair-mates
• Females with the least desirable mate, had the
  highest rate of
• extra-pair copulations

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Extra-pair copulation

• Paternity Analysis
• DNA fingerprinting
• Socially monogamous species (red-winged black
  birds) show extra-pair copulations
• 50 64 of nests

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• Female Choice

• Why should females be choosy ?
• Male display an indicator of good genes
• Male free of parasites
• Acquisition of resources from males (gifts)
• Preexisting sensory biases
• Runaway sexual selection

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• 6. Runaway Sexual Selection

• Example Stalk-eyed flies
• Females preferred males
• with long eyestalks
• 2. Males with long eyestalks left
• more offspring

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• Runaway Sexual Selection

3. Sons inherit long eyestalks, daughters a
preference for long eyestalks (assortative
mating) 4. Each generation males have longer
eyestalks and females prefer longer
eyestalks 5. Positive feedback loop
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Sexual Selection in Plants
Wurmbea dioica
Dimorphic
male
female
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Sexual Selection in Plants

• Female invests more (seeds)
• Access to pollinators limits mating success in
  males more than females
• Increased flower size in males increases
  pollinator visits

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Sexual Selection in Plants

• Male-Male competition
• - pollen tube growth
• (sperm competition)
• Female Choice
• - manipulate pollen tube growth
• - selective seed abortion

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• Sexual Selection

Summary 1. Differences among individuals at
getting mates 2. Asymmetry in limits to
reproductive success - females
of eggs - males of
matings 3. Male competition, female choice
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• Sexual Selection

Summary 4. Reversed when males invest more than
females ( male parental care pipe
fish) 5. Principles of sexual selection in
animals can be applied to flowering plants
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• Sexual Selection

Dr. Ian Jones (Biology) Sexual selection in
Auklets
Aethia pygmaea I. Jones
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Principles of Evolution and Systematics
First Half Topics

• Introduction (Thinking like an evolutionary
  biologist)
• The evidence for evolution (Relatedness of life
  forms)
• Darwin Natural selection (Galapagos Finches )
• Population Quantitative genetics (Genes in
  populations)
• Natural selection Adaptation (Sex and
• 
  Sexual
  selection)
• Adaptation and Diversity

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• Coming Next
• The History of Life
• (in 12 lectures)
• Narrated by Dr. Ted Miller
• Thursday Feb. 22, 2007
• Show times 1030 1145