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Biological Evolution

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Title: Biological Evolution


1
Biological Evolution
2
Evolutionary Bush -- thousands of earlier and
later branches.
3
At any given moment (e.g. the present), all we
see is current diversityall extinct forms are
gone (99.9)
Time ?
4
Four Causes of Evolution
  1. Mutation fundamental origin of all genetic (DNA)
    change.

5
Four Causes of Evolution
  1. Mutation fundamental origin of all genetic (DNA)
    change.

Point mutation
some at base-pair level
6
Four Causes of Evolution
  1. Mutation fundamental origin of all genetic (DNA)
    change.

Crossing-over
others at grosser chromosome level
7
Four Causes of Evolution
  1. Mutation fundamental genetic shifts.
  2. Genetic Drift isolated populations accumulate
    different mutations over time.

In a continuous population, genetic novelty can
spread locally.
8
Four Causes of Evolution
  1. Mutation fundamental genetic shifts.
  2. Genetic Drift isolated populations accumulate
    different mutations over time.

Local spreading of alleles
9
Four Causes of Evolution
  1. Mutation fundamental genetic shifts.
  2. Genetic Drift isolated populations accumulate
    different mutations over time.

Local spreading of alleles
10
Four Causes of Evolution
  1. Mutation fundamental genetic shifts.
  2. Genetic Drift isolated populations accumulate
    different mutations over time.

Spreading process known as gene flow.
11
Four Causes of Evolution
But in discontinuous populations, gene flow is
blocked.
12
Four Causes of Evolution
Variations accumulate without inter-demic exchange
13
Four Causes of Evolution
Of course, this works at many loci
simultaneously
14
Four Causes of Evolution
  1. Mutation fundamental genetic shifts.
  2. Genetic Drift isolation ? accumulate mutations
  3. Founder Effect sampling bias during
    immigration. When a new population is formed,
    its genetic composition depends largely on the
    gene frequencies within the group of first
    settlers.

15
Founder Effect.--
Human example your tribe had to live near the
Bering land bridge
16
Founder Effect.--
to invade settle the New World!
17
Galapagos Finches
Audeskirk Audeskirk, 1993
18
Four Causes of Evolution
  1. Mutation fundamental genetic shifts.
  2. Genetic Drift isolation ? accumulation of
    mutations
  3. Founder Effect immigrant sampling bias.
  4. Natural Selection differential reproduction of
    individuals in the same population based on
    genetic differences among them.

19
Four Causes of Evolution
  • Mutation fundamental genetic shifts.
  • Genetic Drift isolation ? accumulation of
    mutations
  • Founder Effect immigrant sampling bias.
  • Natural Selection reproductive race
  • These 4 interact synergistically

20
Evidence of Evolution
21
Evidence of Evolution
  • Biogeography
  • Geographical distribution of species

22
Evidence of Evolution
  • 2. Fossil Record
  • Fossils and the order in which they appear in
    layers of sedimentary rock (strongest evidence)

23
Fossils
  • Oldest fossils are the approximately 3.465
    billion-year-old microfossils from the Apex
    Chert, Australia
  • colonies of cyanobacteria (formerly called
    blue-green algae) which
  • built real reefs

24
Fossils
  • 1600's - Danish scientist Nicholas Steno studied
    the relative positions of sedimentary rocks
  • Layering is the most obvious feature of
    sedimentary rocks
  • formed particle by particle and bed by bed, and
    the layers are piled one on top of the other
  • any sequence of layered rocks, a given bed must
    be older than any bed on top of it
  • Law of Superposition is fundamental to the
    interpretation of Earth history, because at any
    one location it indicates the relative ages of
    rock layers and the fossils in them.

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Relative and Absolute Dating
  • Relative Dating
  • Can determine the age of fossil with respect to
    another rock or fossil.
  • You compare the depth of a fossils position,
    layers.
  • Some drawbacks include limitations on accuracy.
  • Absolute Dating
  • Can determine the age of a fossil IN YEARS.
  • You determine the age by finding the amount of
    radioactive and nonradioactive isoptope in a
    specimen.
  • Some drawbacks are that it is difficult to
    perform in a lab.

27
Types of Radioactive Isotopes
  • Carbon 14
  • Use for more recent fossils (60,000 yrs old)
  • Can be used with high accuracy
  • Half life of 5,730 years
  • Decays into Nitrogen
  • Potassium 40
  • Used for older fossils
  • Half life of 1.3 billion years
  • Decays into Calcium
  • Less common element

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Half-life for a given radioisotope is the time
for half the radioactive nuclei in any sample to
undergo radioactive decay
30
Half-life for a given radioisotope is the time
for half the radioactive nuclei in any sample to
undergo radioactive decay
31
Evidence of Evolution
3. Taxonomy Classification of life forms.
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Evidence of Evolution
  • Homologous
  • structures
  • Structures that are similar because of common
    ancestry (comparative anatomy)

Turtle
Alligator
Bird
Mammals
Typical primitive fish
34
Evidence of Evolution
  • Comparative
  • Embryology
  • Study of structures that appear during embryonic
    development

35
Evidence of Evolution
  • 6. Molecular biology
  • DNA and proteins (amino acids)

36
History of Theories of Evolution
37
Old Theories of Evolution
  • Jean Baptiste Lamarck (early 1800s) proposed
  • The inheritance of acquired characteristics
  • He proposed that by using or not using its
    body parts, an individual tends to develop
    certain characteristics, which it passes on to
    its offspring.

38
The Inheritance of Acquired Characteristics
  • Example
  • A giraffe acquired its long neck because its
    ancestor stretched higher and higher into the
    trees to reach leaves, and that the animals
    increasingly lengthened neck was passed on to its
    offspring.

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Charles Darwin
  • Darwin set sail on the H.M.S. Beagle (1831-1836)
    to survey the south seas (mainly South America
    and the Galapagos Islands) to collect plants and
    animals.
  • On the Galapagos Islands, Darwin observed species
    that lived no where else in the world.
  • These observations led Darwin to write a book

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Giant Tortoises of the Galápagos Islands
Pinta
Tower
Marchena
Pinta IslandIntermediate shell
James
Fernandina
Santa Cruz
Isabela
Santa Fe
Hood Island Saddle-backed shell
Hood
Floreana
Isabela Island Dome-shaped shell
43
http//www.galapagosislands.com
44
Charles Darwin
  • Wrote in 1859
  • On the Origin of Species by Means of Natural
    Selection
  • Two main conclusions
  • Species were not created in their present form,
    but evolved from ancestral species.
  • Proposed a mechanism for evolution NATURAL
    SELECTION

45
Darwins Observations
  1. Most species produce more offspring than can be
    supported by the environment
  2. Environmental resources are limited
  3. Most populations are stable in size
  4. Individuals vary greatly in their
    characteristics (phenotypes)
  5. Variations that survive are inherited. (genotypes)

46
Natural Selection
  • Individuals with favorable traits are more likely
    to leave more offspring better suited for their
    environment
  • Also known as Differential Reproduction
  • Example
  • English peppered
  • moth (Biston betularia)

47
Modes of Action
  • Natural selection has three modes of action
  • 1. Stabilizing selection
  • 2. Directional selection
  • 3. Diversifying selection

48
1. Stabilizing Selection
  • Acts upon extremes and favors the intermediate.

49
2. Directional Selection
  • Favors variants of one extreme.

50
3. Disruptive Selection
  • Favors variants of opposite extremes.

51
Evidence for Natural Selection
52
Artificial Selection
  • The selective breeding of domesticated plants and
    animals by man.
  • Question Whats the ancestor of the domesticated
    dog?

53
Biodiversity
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Biodiversity
  • Biodiversity
  • increases with speciation
  • decreases with extinction
  • Give-and-take between speciation and extinction ?
    changes in biodiversity
  • Extinction creates evolutionary opportunities for
    adaptive radiation of surviving species

56
Interpretations of Speciation
  • Two theories
  • 1. Gradualist Model (Neo-Darwinian)
  • Slow changes in species overtime
  • 2. Punctuated Equilibrium
  • Evolution occurs in spurts of relatively rapid
    change

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Adaptive Radiation
  • Emergence of numerous species from a common
    ancestor introduced to new and diverse
    environments.
  • Example
  • Hawaiian Honeycreepers

59
Convergent Evolution
  • Species from different evolutionary branches may
    come to resemble one another if they live in very
    similar environments.
  • Example
  • 1. Ostrich (Africa) and Emu (Australia).
  • 2. Sidewinder (Mojave Desert) and
  • Horned Viper (Middle East Desert)

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Coevolution
  • Evolutionary change, in which one species act as
    a selective force on a second species, inducing
    adaptations that in turn act as selective force
    on the first species.
  • Example
  • 1. Acacia ants and Acacia trees
  • Yucca Plants and Yucca moths
  • Lichen

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Extinction
  • Extinction of a species occurs when it ceases to
    exist may follow environmental change - if the
    species does not evolve
  • Evolution and extinction are affected by
  • large scale movements of continents
  • gradual climate changes due to continental drift
    or orbit changes
  • rapid climate changes due to catastrophic events

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Extinction
  • Background extinction - species disappear at a
    low rate as local conditions change
  • Mass extinction - catastrophic, wide-spread
    events --gt abrupt increase in extinction rate
  • Five mass extinctions in past 500 million years
  • Adaptive radiation - new species evolve during
    recovery period following mass extinction

66
Mass Extinctions
http//www.geog.ouc.bc.ca/physgeog/contents/9h.htm
l
Date of the Extinction Event Percent Species Lost Species Affected
65 mya (million years ago) 85 Dinosaurs, plants (except ferns and seed bearing plants), marine vertebrates and invertebrates. Most mammals, birds, turtles, crocodiles, lizards, snakes, and amphibians were unaffected.
213 mya 44 Marine vertebrates and invertebrates
248 mya 75-95 Marine vertebrates and invertebrates
380 mya 70 Marine invertebrates
450 mya 50 Marine invertebrates
67
Community Relationships
68
Niche
  • a species functional role in its ecosystem
    includes anything affecting species survival and
    reproduction
  • Range of tolerance for various physical and
    chemical conditions
  • Types of resources used
  • Interactions with living and nonliving components
    of ecosystems
  • Role played in flow of energy and matter cycling

69
  • Niche is
  • the species occupation and its
  • Habitat
  • location of species
  • (its address)

70
Niche
  • Fundamental niche set of conditions under which
    a species might exist in the absence of
    interactions with other species

Realized niche more restricted set of conditions
under which the species actually exists due to
interactions with other species
71
Species Interaction
72
Competition
  • any interaction between two or more species for a
    resource that causes a decrease in the population
    growth or distribution of one of the species
  • Resource competition
  • Preemptive competition
  • Exploitation competition
  • Interference competition

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Competition
75
Competition
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Predation prey adaptations
  • Avoid detection
  • camouflage, mimics,
  • diurnal/nocturnal
  • Avoid capture
  • flee
  • resist
  • escape
  • Disrupt handling (prevent being eaten)
  • struggle?
  • protection, toxins

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Rewards of Mutualism
  • Food energy and nutrients
  • Protection
  • from other species (competition, predation)
  • from the physical environment (shelter)
  • Gamete or zygote dispersal (the most common of
    all)
  • Pollination and fruit dispersal (between plants
    and animals).

101
Pollination (hummingbird/bee and flowering plants)
  • animals visit flowers to collect nectar and
    incidentally carry pollen from one flower to
    another
  • animals get food and the plant get a pollination
    service

102
Yucca moth and yucca
  • Yuccas only pollinator is the yucca moth. Hence
    entirely dependent on it for dispersal.
  • Yucca moth caterpillars only food is yucca
    seeds.
  • Yucca moth lives in yucca and receives shelter
    from plant.

103
Lichen (Fungi-algae)
  • Symbiotic relationship of algae and
    fungaeresults in very different growth formas
    with and without symbiont.
  • What are the benefits to the fungus?

104
Seed Disperser
  • Many birds and mammals consume fruits and
    incidentally disperse the seeds contained in
    those fruits
  • Animals get food and the plant gets seed
    dispersal (often with fertilizer)

105
Ant-tended plants
  • Ants live inside swollen Acacia thorns or hollow
    stems, e.g. Cecropia trees.
  • Patrol for caterpillars or leaf predators and
    storm out to repel intrudersincluding you!

106
Commensalists
  • Benefit from the host at almost no cost to the
    host
  • Eyelash mite and humans
  • Us and starlings or house sparrows
  • Sharks and remora

107
Parasites
  • Parasites draw resources from host without
    killing the host (at least in the short term).

108
Bibliography
  1. Miller 11th Edition
  2. http//abandoncorporel.ca/medias/evolution.jpg
  3. http//www.ne.jp/asahi/clinic/yfc/fetus.html
  4. rob.ossifrage.net/images/
  5. http//www.mun.ca/biology/scarr/Five_Kingdoms_Thre
    e_Domains.htm
  6. http//www.gpc.peachnet.edu/ccarter/Millerlec5/Mi
    llerlec5.PPT
  7. http//www.dnr.state.md.us/education/horseshoecrab
    /lifecycle.html
  8. http//www.falcons.co.uk/mefrg/Falco/13/Species.ht
    m
  9. http//www.sms.si.edu/irlspec/NamSpecies.htm
  10. http//www.falcons.co.uk/mefrg/Falco/13/Species.ht
    m
  11. http//www.globalchange.umich.edu/globalchange1/cu
    rrent/lectures/complex_life/complex_life.html
  12. http//nsm1.nsm.iup.edu/rwinstea/oparin.shtm
  13. http//www.angelfire.com/on2/daviddarling/MillerUr
    eyexp.htm
  14. http//exobiology.nasa.gov/ssx/biomod/origin_of_li
    fe_slideshow/origin_of_life_slideshow.html
  15. http//www.geo.cornell.edu/geology/classes/Geo104/
    HistoryofEarth.html
  16. http//astrobiology.arc.nasa.gov/roadmap/objective
    s/o2_cellular_components.html
  17. http//pubs.usgs.gov/gip/fossils/
  18. http//hyperphysics.phy-astr.gsu.edu/hbase/nuclear
    /halfli.html
  19. http//www.accessexcellence.org/AE/AEPC/WWC/1995/t
    each_rad.html
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