How do organisms adapt and change over time?

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How do organisms adapt and change over time?
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What makes this flounder fish so unusual? And,
how did it get this way?
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Charles Darwin (1809-1882) Sailed around the
world 1831-1836
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Galapagos Turtles
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Darwins Travels Revealed

• Lots of different species!
• These island observations led him to develop the
  theory of evolution!

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Natural Selection

• The process where plants/animals with favorable
  traits survive and reproduce.
• Occur because of a mutation in the DNA or the
  environment.

Ex. Organisms adapt to their environment.
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Natural Selection is NOTSelective Breeding!

• Nature provides variation, humans select
  variations that are useful.
• Ex a farmer breeds only his best livestock

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Natural Selection

• Traits that help an organism survive in the
  environment are selected.

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Example of Natural Selection

• Peppered Moths

• Darwins Finches

• The isolation of the birds on an island caused
  the finches to develop lots of different kinds of
  beaks.

• A study of different colored moths disappearing
  and appearing in an area.

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Summary of Darwins Theory

• 1. Organisms differ variation is inherited
• 2. Organisms produce more offspring than survive
• 3. Organisms compete for resources
• 4. Organisms with advantages survive to pass
  those advantages to their children
• 5. Species alive today are descended with
  modifications from common ancestors

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Is this a correct theory?
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Mimicry

• Physically or actively looking like another
  organism.
• Ex. A walking stick insect.

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How do we know that organisms use natural
selection?
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Fossil Records

• Solid remains or imprints of once-living
  organisms.
• Are formed from layers of sediment and minerals
  replacing bone.

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Evidence of Evolution

• Shows that living things have evolved
• Show the history of life on earth and how
  organisms have changed over time.

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Relative Dating

• Can determine a fossils relative age
• Date age comparing with other fossils
• Drawbacks provides no info about age in years

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Absolute Dating

• Can determine the absolute age in numbers
• Performed by radioactive dating based on the
  amount of remaining radioactive isotopes
• Drawbacks - part of the fossil is destroyed
  during the test

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Carbon-14 Dating
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What do fossil records and skeletal records show
Similarities!
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Vestigial Structures

• Once useful structures that are still visible.
• Ex. The hind-limb bones deeply embedded inside
  the whale or the changes in the horse.

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Can you find the vestigial structures?
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Homologous Structures

• Similar structures in different organisms.
• Ex. Hand Bones

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Homologous Body Structures
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Embryonic Structures

• Embryos of vertebrates are not the same but look
  similar.
• (And, grow into different organisms.)

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How do organisms ensure the survival of there
species?
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Natural Selection Must Haves

• Overproduction of off-spring
• Inherited variation or differences
• Struggle to survive
• Successful reproduction

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Possible Reasons for Natural Selection

• Variation In Genes
• Competition
• Pollution/Mutations
• Environmental Changes
• Separation
• Adaptation
• Division

See the pictures and examples on Pg.162 164
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So, why is it important that animals and plants
adapt to their environment?List and explain at
least 3 reasons or examples you think animals
might adapt.