Natural Selection - Evolution

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Natural Selection - Evolution
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What is it?

• Charles Darwin (1859)
• HMS Beagle
• Galapagos Islands
• Studied Anatomy
• of Finches

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Charles Darwin

• After Charles Darwin graduated from college, he
  served as naturalist on a ship called the HMS
  Beagle. During a voyage around the world, Darwin
  collected thousands of plant and animal samples.

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Darwins Finches

• Darwin noticed that the finches of the Galápagos
  Islands were a little different from the finches
  in Ecuador. And the finches on each island
  differed from the finches on the other islands

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Darwins thinking

• Ideas About Breeding The process in which
  humans select which plants or animals to
  reproduce based on certain desired traits is
  called selective breeding.
• Ideas About Population Only a limited number of
  individuals survive to reproduce. Thus, there is
  something special about the offspring of the
  survivors.

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Competition for mates

• Many species have so much competition for mates
  that interesting adaptations result. For example,
  the females of many bird species prefer to mate
  with males that have colorful feathers.
• Sometimes, drastic changes that can form a new
  species take place. The formation of a new
  species as a result of evolution is called
  speciation.

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Influences on Darwin

• Thomas Malthus wrote a book stating that humans
  have the potential to reproduce rapidly,
  eventually overrunning the food supply
• This led Darwin to realize that all species can
  reproduce rapidly, those who survive must pass on
  traits to their offspring to help them survive

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Darwins theory of natural selection

• What Is Natural Selection? Darwin proposed the
  theory that evolution happens through a process
  that he called natural selection. Individuals
  that are better adapted to their environment
  survive and reproduce more successfully than less
  well adapted individuals.
• Genetics and Evolution Today, scientists have
  found most of the evidence that Darwin lacked.
  They know that variation happens as a result of
  differences in genes.

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What evidence is there?

• In order for natural selection, or any other
  theory of evolution to be accurate, there needs
  to be some physical evidence supporting it.
  Following are some clues scientists have used to
  piece together the history of living things on
  Earth.

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Fossils

• CuvierExtinction existed
• Shape and Purpose

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What are fossils?

• The remains or imprints of once-living organisms
  found in layers of rock called fossils.
• By studying fossils, scientists have made a
  timeline of life known as the fossil record. The
  fossil record organizes fossils by their
  estimated ages and physical similarities.

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Anatomy

• Homologous Structures
• Same, but
• different function
• Analogous Structures
• Same function, but different structure

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Anatomy 2

• Vestigial Structures
• No longer needed/used

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Biochemistry

• Study DNA
• Genetic Technology
• RFLPs
• Gel Electrophoresis

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Comparative Embryology

• Study Embryos of Different Organisms

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Adaptations

• What is it?
• Who displays it?
• Why does it happen?

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Mimicry

• a superficial resemblance of one organism to
  another or to natural objects among which it
  lives that secures it a selective advantage (as
  protection from predation)

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Camouflage
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Resistance

• Mostly bacteria and viruses

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Changes in Populations

• Adaptation to Hunting People hunt elephants for
  their tusks. As a result, fewer of the elephants
  that have tusks survive to reproduce, and more of
  the tuskless elephants survive.
• Insecticide Resistance A few insects in a
  population may be naturally resistant to a
  chemical insecticide. These insects pass their
  resistance trait to their offspring, and an
  insect population gradually becomes resistant to
  the insecticide.

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