Evolution through Natural Selection

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Evolution through Natural Selection
How has life changed over time?
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What is the definition of Adaptation?

• An inherited characteristic that improves an
  organisms ability to survive and reproduce in a
  particular environment.

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Who were the two main scientists that studied
evolution?

1. Lamarck
2. Darwin

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What were Lamarcks three main ideas?

• Desire to Change organisms change because they
  want to better themselves.
• Use and Disuse organisms can change their shape
  by using their body in different ways.
• Passing on Acquired Traits Acquired traits are
  passed onto offspring.
• Evolution of an individual not population.

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In The Origin of Species, what were Darwins two
main points?

• Descent with modification
• The species of organisms that we see today
  descended from ancestral species.
• As these ancestral species spread all over the
  world, they developed different adaptations.

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In The Origin of Species, what were Darwins two
main points.

• 2. Natural Selection
• Process by which individuals with inherited
  characteristics well-suited to the environment
  leave more offspring on average than do other
  individuals.
• Natural selection is the mechanism for evolution.

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What is evolution through natural selection?

• Individual organisms in nature differ from one
  another. Some of this variation is inherited.
• 2. Organisms in nature produce more offspring
  than can survive. Many of these offspring do not
  reproduce.

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What is evolution through natural selection?

• More organisms are produced than can survive,
  members of each species must compete for limited
  resources.
• 4. Each organism is unique and has different
  advantages and disadvantages in the struggle for
  existence.

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What is evolution through natural selection?

• Individuals best suited to their environment
  survive and reproduce successfully passing
  their traits to their offspring.
• 6. Species change over time. Over long periods,
  natural selection causes changes that may
  eventually lead to new species.

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What is evolution through natural selection?

• Species alive today have descended with
  modifications from species that lived in the
  past.
• All organisms on Earth are united into a single
  tree of life by common descent.
• Evolution of population NOT individual.

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With a partner, explain how this diagram
illustrates Darwins theory of evolution through
natural selection.
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Birds on an Island Simulation of Natural
Selection

• During his travels, Darwin noticed that there was
  tremendous variation in the Galapagos Island
  finches.
• What type of environmental changes could favor
  large beaks? Thin, sharp beaks?