Happy Tuesday!

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Happy Tuesday!

• Submit The Peppered Moth WS
• Title a new page in your notebook The Theory of
  Biological Evolution
• Finish Presentations (Per 4 and 6 only)
• Evidence Projects group scores _at_ end of class.
  Can someone set an alarm for 3 minutes before the
  bell? Thank you!

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Discuss!

• A volcano erupted on an island. The ash released
  from the volcano changed the acidity (pH) of the
  soil from the level it had been for hundreds of
  years. This significant change resulted in new
  environmental pressures on species in the soil.
  Which of the following is a likely outcome of
  these pressures?
• Some species will disappear from the soil because
  they do not have individuals with traits that
  allow them to survive in more acidic soil.
• Only some species will generate the needed
  mutations to adapt to the change in pH other
  species will become extinct.
• Most species gain additional genetically-based
  traits, and this increase in complexity allows
  them to live in the more acidic soil.
• Individuals in each species will evolve the
  traits necessary to survive under these new
  conditions.

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• A ship that had been used for many years in
  arctic exploration was sold and moved to a harbor
  in the warm waters of the Caribbean. Worms that
  had lived on the ship bottom crawled off in the
  warm waters and attempted to attach to other
  ships in this tropical area where there were no
  similar worms. Some of the worms were able to
  survive and reproduce. What would you expect to
  happen to this group of worms over many
  generations in this new environment?
• The worms will mate and produce offspring just as
  they did in their previous environment, and the
  groups traits will likely remain unchanged after
  many generations.
• The worms will gain new, more complex traits
  through natural selection that will help them
  better adapt to the warmer waters because natural
  selection leads to more complex and better
  adapted organisms.
• Worms possessing genetic variations that help
  them to survive and thrive in the new environment
  will leave more offspring than others lacking
  those traits. Over time, the proportion of the
  worm population with these adaptive traits will
  likely increase.
• The mutation rate will increase in this group of
  worms in order to promote evolution.

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The Theory of Biological Evolution
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The Theory of Evolution, defined

• All living species are descendants of ancestral
  species and are different from present day ones
  due to the cumulative change in the genetic
  composition of a population
• In a nutshell Populations of living things came
  from other life but look and behave differently
  because of genetic change.

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Charles Darwin (1809-1882)

• Father of the theory of Evolution
• Suggested that natural selection is the mechanism
  by which species evolve over geologic time.
• Proposed Descent with Modification
• All organisms on Earth are related
• through some unknown ancestral
• type that lived long ago.

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History of Evolution Theory

• As with any scientific theory, Evolution Theory
  has been developed through many generations of
  scientists interpreting new evidence to refine
  and expand our understanding of biological change
  across time.
• Darwin and Wallace (Evolution)
• Gregor Mendel (Genetics)
• Franklin, Watson Crick (Genetics)

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The Nuts and Bolts of Evolution

• Populations change, not individuals.
• Evolution is like a tree. Many branches emerged
  from a common beginning, some branches died off
  (extinction), others branched multiple times
  (diversity)

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The Nuts and Bolts of Evolution

• Niche
• A job or activity that is very suitable for
  someone.
• I have my dream job. I have found my niche in
  society
• An environment that has all the things that a
  particular form of life needs in order to live.
• The arctic fish have found their niche in cold
  waters due to the adaptations in their cell
  membranes
• The great diversity of life is the result of over
  3.5 billion years of evolution, filling every
  available niche with life forms.

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Niche An environment that has all the things
that a particular form of life needs in order to
live.

• Discuss with a neighbor a possible niche for
  a/an
• Elephant
• Whale
• Bacterium
• Cactus
• Why are these life forms able to fill these
  niches?
• How have these life forms filled these niches?

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The Origin of Species

• Darwin developed two main ideas
• Evolution explains lifes unity and diversity
• Natural selection is a cause of adaptive evolution

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Darwins Tree of Life
Is there a connection to this?
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Factors involved in Biological Evolutioninterpret
ed through Observations and Inferences from On
the Origin of Species
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(No Transcript)
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Overproduction

• Most species can (and do!) produce far more
  offspring than are needed to maintain the
  population.
• Populations remain more or less constant
  (stable) because a small fraction of offspring
  live long enough to reproduce.

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Competition

• Living space and food are limited, so offspring
  from each generation must compete among
  themselves in order to live.

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(Genetic) Variation

• Characteristics in individuals in any species are
  not exactly alike.
• Example Differences for Homo sapiens can be
  exact size or shape of body, strength in running,
  or resistance to disease.

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Natural Selection

• Nature (environment) selects for living
  organisms with better suited inherited traits to
  survive and reproduce in that particular
  environment.
• Survival of the Fittest what does fitness
  mean?
• Fitness likelihood of survival AND
  reproduction. Both factors must be at play.

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Sun Bear
Polar Bear

• For the sun bear (native to SE Asia), long fur is
  harmful because the bear will overheat.
• What does long fur do to a sun bears fitness?
• Polar bears use long fur to absorb heat in the
  cold arctic environment.
• What does long fur do to a polar bears fitness?

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• Think about color
• What is the best color for absorbing heat?
• What is the best color for reflecting heat?
• Traits balance out, resulting in the best fitness
  possible.
• Why cant polar bears be black, even though they
  would be warmer?
• Why cant a sun bear be white, to keep it more
  cool?
• The ability to hunt is MORE valuable than color
  of fur for keeping the bear alive.

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Sun Bear
Polar Bear
Helpful mutations over many generations
Adaptations This is why species appear to be
adapted to their environment.
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Adaptation

• An adaptation is an inherited trait that
  increases an organisms chance of survival and
  reproduction in a given environment.
• Note This is where the verbal shortcut of the
  term adapt is used (painfully) incorrectly.

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Speciation

• Over many generations, favorable adaptations (for
  a particular environment) gradually accumulate in
  a species and bad (unfavorable) ones disappear.
• Eventually, accumulated changes become so great,
  the result is a new species.
• Takes many generations. Does that mean it takes a
  lot of time? Why or why not?

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Whats next?

• Natural selection does not move in a
  pre-determined direction! The changing earth
  determines what will and can survive.

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The four factors ()

• Biological evolution is a consequence of 4
  factors working together. Without all factors,
  species change will not occur.
• Overproduction
• Competition
• Genetic Variation
• Natural Selection

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Pencils down for a class quiz!Which factors of
evolution are depicted in the following pictures?
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Diagram 1
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Diagram 2
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Diagram 3
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Diagram 4
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Key!
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Competitionor Overpopulation
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Variation
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Speciation
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Adaptation
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Your Task

• Begin the Lecture Review Questions. You can work
  with a group or partner, but write down your own
  answers (i.e., in your own words). Use your notes
  to help you.
• Due on the day of test review. Dont
  procrastinate!

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Modeling Natural Selection through the
Evolution of Lemurus hypotheticus
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The Evolution of Lemurus hypotheticus

• Population The species, Lemurus hypotheticus.
• Environment Floornchair Rainforest
• Resources Food Landing on a Chair
• Variation The slight differences between
  individuals brought to you by mutation and
  genetic recombination (aka sexual reproduction)

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Simulation The Evolution of Lemurus hypotheticus

1. No variation
2. Monopeds
3. Opti-nots
4. Audio-nots
5. Vertically challenged
6. Bad SOD
7. Tunnel Vision
8. Manual Nots
9. PITN
10. Lotsamass