How does evolution happen
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How Does Evolution Happen?. Chapter 7 Section 2. Charles Darwin (1809-1882) Sailed around the world 1831-1836. 22 yrs old HMS Beagle Ship’s naturalist Galapogos Islands Discovered: Adaptations Natural Selection Sucessful Reproduction Inherited Variations Competition

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How Does Evolution Happen?

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How does evolution happen

How Does Evolution Happen?

Chapter 7 Section 2


Charles darwin 1809 1882 sailed around the world 1831 1836

Charles Darwin (1809-1882) Sailed around the world 1831-1836

  • 22 yrs old

  • HMS Beagle

  • Ship’s naturalist

  • Galapogos Islands

  • Discovered:

    Adaptations

  • Natural Selection

    Sucessful Reproduction

    Inherited Variations

    Competition

    Overproduction

  • Theory of Evolution –

What did he not know about??GENETICS


How did tortoises and birds differ among the islands of the galapagos

How did tortoises and birds differ among the islands of the Galapagos?

  • Each island had its own type of tortoises and birds that were clearly different from other islands


How does evolution happen

Finches on the isolated islands of the Galapagos developed different beaks because of the food they ate. They adapted to the food sources available.

F


How does evolution happen

Natural selection

Individuals that are better adapted

to survive in an environment are able to live to reproduce and

pass on their genetic material.

Adaptation and natural selection occur

together as organisms change over time.


How does evolution happen

What factors affect how

natural selection works?

Overproduction– species produce more offspring than the environment can hold

Competition– offspring must compete for resources. Those that succeed, live to pass on genetic information.

Inherited Variations– offspring always differ from each other. Sometimes these variations help individuals be more successful.

Successful Reproduction– organisms best adapted to their environment are likely to have many offspring that survive.

The successful variations accumulate over many generations which causes the species to change over time.


How does evolution happen

An example of

changes in

a population

over time.

http://evolution.berkeley.edu/evolibrary/article//bergstrom_02


How does evolution happen

An Example of Natural Selection

The Peppered Moths of Manchester, England


How does evolution happen

Peppered Moths of England – Natural Selection

Before the industrial revolution in Britain most peppered moths were of the pale variety that were well camouflaged against the pale birch trees that they like to sit on. Moths with the mutant black coloring were easily spotted and eaten by birds - giving the white peppered variety an advantage.


How does evolution happen

Peppered Moths of England – Natural Selection

http://www.bbc.co.uk/schools/gcsebitesize/biology

Then the industrial revolution came along in the 19th century. Airborne pollution in industrial areas darkened the birch tree bark with soot, and now the mutant black-peppered moths blended better against the darkened bark, while the white variety became much more vulnerable to predators. Over time the mutated black peppered moths were naturally selected to survive and became far more numerous in urban areas than the pale variety.


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