What is evolution
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What is evolution?. Evolution is…. Change over time Process by which modern organisms have descended from ancient organism THEORY!! Simply stated. Creationism. Theory that life on Earth was formed by a divine being. Science vs. Faith (not mutually exclusive). Hutton & Lyell.

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Evolution is
Evolution is…

  • Change over time

  • Process by which modern organisms have descended from ancient organism

  • THEORY!!

  • Simply stated


Creationism
Creationism

  • Theory that life on Earth was formed by a divine being.

  • Science vs. Faith (not mutually exclusive)


Hutton lyell
Hutton & Lyell

  • Concluded that the Earth is extremely old and that the processes that changed the Earth in the past are the same SLOW processes that operate in the present.


Malthus
Malthus

  • Reasoned that if the human population grew unchecked, there wouldn’t be enough living space and food for everyone.


Lamarck
LaMarck

  • Evolution by acquired traits

    • Organisms developed traits during their lifetime .

    • Give those traits (big muscles) to their offspring.

  • Example

    • In reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspring.

  • Not accepted as valid


Darwin s view of evolution
Darwin’s view of Evolution

  • Father of modern evolution theory

    • Giraffes that alreadyhave long necks survive better.

    • Leave more offspring who inherit their long necks.

    • Believed in descent with modification.

    • Wrote a book: The Origin of Species


Descent with modification
Descent with modification

  • All species—living and extinct– are descended from ancient common ancestors.

  • Over many generations, adaptations could cause successful species to evolve into new species making them better suited for their environment.

  • Examples: tiger’s claws; colors, like those that make camouflage or mimicry possible; or physiological functions, like the way a plant carries out photosynthesis.


Survival of the fittest
“Survival of the fittest”

  • If you are better fit for your environment, you will survive.

  • You will reproduce.

  • Over time, population will be more like you.

  • Fitness: the ability to survive and reproduce.


Voyage of the hms beagle
Voyage of the HMS Beagle

  • Stopped in Galapagos Islands

    • 500 miles off coast of Ecuador


Darwin found many unique species
Darwin found…many unique species

Many of Darwin’s observations made him wonder… Why?


Galapagos islands
Galapagos Islands

  • Example: Finches

    • 13 species of finches

    • Found on different islands

    • Beak size and shape varied

    • Ate different food

  • Finches had adapted to best obtain food in their environment.


Natural selection
Natural Selection

  • Organisms with variations well suited to the environment survive and leave more offspring at a fast rate.

    • You have the genes to be successful in your environment or you don’t

  • Variety already exists, some varieties better fit to environment than others.



  • Variety is the spice of life
    Variety is the spice of life…

    • Variation: differences between members of the same species

    • Cause of variation = mutations

    • Variation is important to survival!

    • Example: Peppered Moth


    Example
    Example:

    Population A

    Population B

    Which population of hares has a better chance of survival as a species?


    Population b
    Population B

    • Because it has more genetic variation than population A so there will be some individuals that are more fit if the environment were to change. Thus the species has a higher chance of survival.


    Take home message
    TAKE HOME MESSAGE:

    Genetic variation increases a species’ chance of survival

    good

    survival

    Variation


    Artificial selection
    Artificial Selection

    The selective breeding of domesticated plants and animals by man. Provides variations that humans find useful.

    Example: Dog breeds, & flowers


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