EVOLUTION

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EVOLUTION

• What is evolution?

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• Genetically based change in phenotype over
  generations
• Process in which species undergo modifications
  over generations. In some cases these changes
  can result in the formation of a new species.

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Why does evolution occur?

• Evolution is not survival of the strongest, or
  failure of the weakest. Evolution is not fair
  it's not predictable it's not kind. Nor is it
  cruel, or chaotic, or unfair, for that matter.
  It's what happens when environmental pressures
  change.
• Michael Jon Jensen
• This essay was originally presented as the
  Keynote Speech at the Illinois Association of
  College and Research Libraries (IACRL) Biannual
  Meeting, Bloomington/Normal, IL, March 30, 2006.

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• What changes do we see over time why?
• From dog sized in rainforests to large animals on
  the plains
• Its multi-toed feet, adapted for walking across
  the forest floor, evolved into single-toed hooves
  more suited for running over open country

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• Darwins Voyage

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DARWINS PRINCIPLES

• Descent with modification
• Natural selection

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What is natural selection?

• Process
• Differential adaptations of organisms with
  beneficial traits
• The environment selects for those traits that
  will be passed on with greater frequency

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What is meant by variation?
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What is meant by adaptation?

• Any variation that increases an organisms chance
  for survival
• When does variation become an adaptation?
• What does adaptation depend on?
• The environment

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Who said characteristics or traits (variations)
that are acquired in ones lifetime and are passed
on (inherited)?
Lamarck

• An extension of Lamarck's ideas of inheritance
  that has stood the test of time, however, is the
  idea that evolutionary change takes place
  gradually and constantly

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Example from Lamarck

• This weight lifter has built up arm muscles from
  working hard
• According to Lamarck the offspring should have
  strong muscles

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DARWINS THEORY KEY POINTS

• Variations exist
• Variations can be inherited
• Populations tend to overproduce
• There is a struggle for survival due to limited
  resources
• Animals that are best fit, survive and reproduce
  (fitness is relative to a specific time and
  location)
• There is an evolution of the population with the
  traits of the fittest becoming most frequent.

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Classic example, the Peppered Moth
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• As a result, species must change through time in
  order to survive.
• Organism that change most successfully, they
  survive and reproduce are the fittest.

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• Antibiotic
• Resistance

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Endnagered species, why?
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Types of Adaptations

• For each of the following slides list at least
  one of example of each type of adaptation
• Morphological
• Physiological
• Behavioral

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WHAT ARE DIFFERENT TYPES OF EVIDENCE TO SUPPORT
THE THEORY OF EVOLUTION?

• EMBRYOLOGY
• FOSSILS
• MORPHOLOGY
• BIOCHEMICAL (DNA)

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EMBRYOLOGY
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FOSSILS
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HOMOLOGOUS STRUCTURES (MORPHOLOGY)
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DNA EVIDENCE
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Organisms are classified in the same species if
they are potentially capable of interbreeding and
producing fertile offspring. In general, they
must be in the same geographical location.
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Organisms may appear to be alike and be different
species. For example, Western meadowlarks and
Eastern meadowlarks look almost identical to one
another, yet do not interbreed with each
otherthus, they are separate species according
to this definition. The Western meadowlark (left)
and the Eastern meadowlark (right) appear to be
identical, and their ranges overlap, but their
distinct songs prevent interbreeding.
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Organisms may look different and yet be the same
species. For example, look at these ants. You
might think that they are distantly related
species. In fact, they are sisterstwo ants of
the species Pheidole barbata, fulfilling
different roles in the same colony.
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How does a new species form?
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• During allopatric speciation, a population splits
  into two geographically isolated allopatric
  populations.
• New speciation starts because populations are
  prevented from interbreeding.
• Scientists think that geographic isolation is a
  common way for the process of speciation to
  begin rivers change course, mountains rise,
  continents drift, islands break away from the
  main lands, habitats fragment and become
  unfavorable, organisms migrate, and what was once
  a continuous population is divided into two or
  more smaller populations

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• Macroevolution is the process by which new
  species are produced from earlier species
  (speciation). It also involves processes leading
  to the extinction of species.
• Microevolution is evolutionary change at the
  level of the population, and is defined by
  changes in allele frequency within the population
  over time. Such changes take place over
  relatively short time periods.
• Accumulated gradual changes in two populations
  that preclude their interbreeding may lead to the
  formation of a new species.

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Microevolution Speciation
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Genetic Drift
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Bottleneck Effect
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3 Modes of Natural Selection
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Common Example of Stablizing Selection
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Organisms may look different and yet be the same
species. For example, look at these ants. You
might think that they are distantly related
species. In fact, they are sisterstwo ants of
the species Pheidole barbata, fulfilling
different roles in the same colony.
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Directional Selection Rough to Smooth
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Disruptive Selection
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• Cant have Hardy Weinberg Equilibria if these are
  occuring

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Non Random Mating Artificial Selection