WARM UP 123

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WARM UP 1/23
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WARM 1/31/05

• What is the definition of Evolution?
• What is the definition of genetics?
• Give an example of how evolution can occur.

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Darwins Theory of Evolution
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Evolution

• Change over time (allele frequency in a gene
  pool!)
• Process by which modern organisms have
  descended from ancient organisms

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Theory
A well-supported testable explanation of
phenomena observed in the natural world
Not a hypothesis or educated guess
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Theory

• Scientific Law Summary of observations (what
  happened)
• Hypothesis This is an educated guess based upon
  observation
• Theory A theory is more like a scientific law
  than a hypothesis. A theory is an explanation of
  a set of related observations or events based
  upon proven hypotheses and verified multiple
  times by detached groups of researchers. In
  general, both a scientific theory and a
  scientific law are accepted to be true by the
  scientific community as a whole

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Theory

• Some scientific theories include the theory of
  evolution, the theory of relativity, and the
  quantum theory. All of these theories are well
  documented and proved beyond reasonable doubt.
  Yet scientists continue to tinker with the
  component hypotheses of each theory in an attempt
  to make them more elegant and concise, or to make
  them more all-encompassing. Theories can be
  tweaked, but they are seldom, if ever, entirely
  replaced.

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Who was Charles Darwin?

• Born 1809 in England
• Studied medicine and theology
• Joined HMS Beagle crew in 1831
• Ship naturalist
• Collected specimens
• Made observations
• Recorded thoughts
• READ!

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Route of HMS Beagle
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Darwins Observations

• Patterns of Diversity
• Plants animals well suited to environments
• Similar ecosystems had different animals present

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Darwins Observations, cont.

• Fossils preserved remains of ancient organisms
• Some resembled living organisms
• Some had no living counterpart

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The Galapagos Islands

• Small group of islands west of South America
• Observed many different organisms on the islands
• Tortoises
• Finches
• Islands had different climates and different
  species

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• Darwin observed that the characteristics of many
  animals and plants varied noticeably among the
  different islands of the Galapagos

What would cause such variation to occur?
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Influences on Darwin

• Hutton
• Geologist, late 1700s
• Proposed geological forces acted extremely slowly
• Proposed the Earth was millions of years old
  (instead of thousands)

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Influences on Darwin

• Lyell, mid 1800s
• Processes that shaped Earth millions of years ago
  continue today
• volcanoes, earthquakes, erosion
• Over long periods of time, significant geologic
  changes can occur

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Lamarcks Evolution Hypothesis

• Early 1800s
• one of the first scientists to recognize that
  living things changed over time
• Tendency towards perfection
• Organisms continually change
• Acquire characteristics that help them live more
  successfully

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Lamarcks Evolution Hypothesis

• Use and Disuse
• Organisms could alter the size or shape of organs
• Trying to use organs developed them
• Not using organs led to them decreasing in size

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Lamarcks Evolution Hypothesis

• Inheritance of Acquired Traits
• Thought acquired traits could be inherited
• We now know how traits are inherited (not by
  behavior but by ________?)

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Malthus

• English economist, late 1700s
• Noted babies being born faster than people were
  dying
• Human population growing sooner or later not
  enough living space and food
• War, famine, and disease slowed down growth

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Darwins Connection

• Darwin realized the same theory could be applied
  to plants and animals
• Many plants and animals produce lots of offspring
  and most do not survive or reproduce