Evolution

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Evolution

• The process in which species change over time.

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Charles Darwin

• Was a British naturalist.
• He was hired to travel on the HMS Beagle to learn
  as much as he could about the living things he
  saw on the voyage.

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The HMS Beagle

• Traveling with the ship, Darwin observed many
  different plants and animals.
• He was very curious about why these living things
  were so different from the ones he studied in
  England.
• This curiosity led to develop The theory of
  _______________ by natural selection.

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The Galapagos Islands

• The Beagle traveled to the Galapagos Islands of
  South America.
• Here, Darwin made some of his most important
  observations!

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The Galapagos Islands

• Darwin observed that the __________ of the
  Galapagos were very different from one island to
  the next.
• The beaks of the birds varied in shape and size.

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Darwins Finches

• As Darwin studied his finches, he noticed that
  each species was well suited to the life it led.
• Insect eaters sharp, needlelike beaks
• Seed eaters strong, wide beaks

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The Galapagos Islands

• Darwin also noticed that the iguanas that lived
  on the island were different from the iguanas on
  the mainland.
• Island Iguanas had large claws.
• Mainland Iguanas had small claws.

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The Galapagos Iguanas

• Darwin realized that the claws of the iguana were
  also beneficial to the life it led.
• The large claws of the island iguanas kept them
  from slipping off of the rocks.
• The small claws of the mainland iguanas allowed
  them to climb trees where they ate leaves.

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Galapagos Iguanas
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Life After the Beagle

• ________________ are traits that help organisms
  survive and reproduce.
• Beak shape and claw length are examples of this.
• When Darwin returned home from life on the
  Beagle, he tried to understand how these specific
  traits arose.

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Darwins Conclusion

• Darwin reasoned that arrived on one of the
  Galapagos Islands faced conditions that were
  different from the mainland.
• He came up with the conclusion that species must
  gradually change over many generations to become
  better adapted to their environment.
• This change over time is called _____________.

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The Theory of Evolution

• What is a scientific theory?
• A well-tested concept that explains a wide range
  of observations.
• The theory of evolution is what scientists have
  determined to be true based on significant
  amounts of research, observations, and evidence
  to back this up.

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How does evolution happen?

• Darwin still didnt know one thing how does
  evolution happen?
• Darwin bred pigeons. He allowed only pigeons with
  many tail feathers to mate. This produced pigeons
  with two or three times the usual number of
  feathers.
• This process is called ___________
  ______________.
• Maybe, he thought, something happens like this in
  nature!

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Selective Breeding in Nature

• Why are certain traits selected for (and how) in
  nature?
• ____________ _____________ is the process by
  which individuals that are better adapted to
  their environment are more likely to survive and
  reproduce than other members of the same species.

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The Origin of Species

• Charles Darwin, along with biologist Alfred
  Russel Wallace, published his explanation in a
  book called The Origin of Species.

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Natural Selection

• Factors that affect the process of natural
  selection
• Overproduction
• Competition
• Variations

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Overproduction

• Most species produce far more offspring that can
  possibly survive.
• Sea turtles lay more than 100 eggs.
• If all of the young turtles survived, the sea
  would be full of turtles!
• But this is not the case not all of the
  offspring will survive.

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Overproduction

• Sea Turtles are organisms that overproduce

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Natural Selection

• Factors that affect the process of natural
  selection
• Overproduction
• Competition
• Variations

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Competition

• Offspring must compete with each other to
  survive.
• Offspring compete for resources- food, water,
  living space, etc.
• Only some will escape from predators.
• Only a few offspring will survive long enough to
  reproduce.

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Competition

• Sea Turtle hatchlings compete for space.

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Natural Selection

• Factors that affect the process of natural
  selection
• Overproduction
• Competition
• Variations

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Variations

• Any difference between individuals in the same
  species is called a variation.
• We know that this is a result of genetics.
• Some variations make certain individuals better
  adapted to their environment.

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Variations

• Some newly hatched turtles are able to swim
  faster than others.

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Natural Selection

• Individuals that are better adapted to their
  environment are more likely to survive and
  reproduce.
• When these well-adapted individuals reproduce,
  their offspring inherit the alleles for these
  adaptations.
• Thus

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Natural Selection

• The environment has selected these well-adapted
  organisms to be the parents of the next
  generation.
• Nature has selected natural selection
• Over a long period of time, natural selection can
  lead to evolution (the changing of a species).
• Helpful variations gradually accumulate in a
  species, while unfavorable ones disappear.

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