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Succession

Lesson 6

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Houston

NEW: MINUTE MAID PARK

OLD: ASTRODOME

What would happen if humans just left the old stadium?

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Atlanta

OLD: GEORGIA DOME

NEW: MERCEDES-BENZ STADIUM

What would happen if humans just left the old stadium?

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Wrigley Field

What would happen if humans just disappeared?

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VIDEO: Life After People

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Succession

  • ecosystems change over time
  • succession is a series of gradual changes that result in the replacement of one community of plants and animals by another
    • there are two types of succession:

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PRIMARY

SUCCESSION

PRIMARY

SUCCESSION

SECONDARY

SUCCESSION

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PRIMARY

SUCCESSION

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Primary Succession

  • this happens in an area that has never had life before
    • EXAMPLE: a lava flow, once cooled, creates an area of new rock

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Primary Succession

  • the first organisms to colonize �(move into) the bare rock are lichens
  • lichens are made of a algae and an fungus

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    • lichen slowly grows thicker, incorporating bits of dust and rock particles to form a very thin layer of soil

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uses photosynthesis to capture the energy of the sun and make sugars, which it shares with the fungus

ALGAE

provides structure for the algae and produces an acid that helps to capture nutrients from the rock and the air

FUNGUS

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Primary Succession

  • once there is a thin layer of soil, mosses are able to colonize the area
    • as the mosses die and decay, the layer of soil becomes thicker
  • once enough soil has gathered, small plants are able to colonize the area
    • the plants add to the soil layer when they �die and because the roots of the plants �help to break up the rock further
  • eventually the area develops �enough soil for grasses and then �trees to grow and then animals �to move into the area

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Primary Succession

NOTICE THE THICKNESS OF THE SOIL

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Primary Succession

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SECONDARY

SUCCESSION

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Secondary Succession

  • this happens in an area that has had life before but been disturbed
    • EXAMPLE: after a large forest fire
  • because life already existed in the area, there is already soil which contains nutrients for plants

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Secondary Succession

  • the first organisms to colonize the area are grasses and wildflowers
    • the seeds of these plants blow in from other areas nearby
  • the seeds grow into plants, which eventually die and decay, enriching the soil with their nutrients

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Secondary Succession

  • larger plants like bushes and small trees are able to grow in the enriched soil
  • the presence of larger plants provides habitat for small animals, which now start the colonize the area
  • eventually the area supports larger trees and animals

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Secondary Succession

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Succession

  • succession is a series of gradual changes that result in the replacement of one community of plants and animals by another

PRIMARY

SUCCESSION

STARTING FROM SCRATCH

SECONDARY

SUCCESSION

RECOVERY

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DISCUSS:

How do we think humans �interfere with succession?

PRIMARY

SUCCESSION

STARTING FROM SCRATCH

SECONDARY

SUCCESSION

RECOVERY

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