Interactions Among Organisms
Competition, Predation and Symbiosis
Symbiosis:
Mutualism, Predation and Commensalism
Click this link to see examples of different types of symbiotic relationships among ocean organisms.
Energy Flow in Ecosystems
The arrows show the direction that energy moves. Note that any organism that dies before being eaten will have its energy transfered to the decomposers (like bacteria and mushrooms, which are a type of fungus).
(Obviously, the "omnomnomnivore" is not real, but it's still pretty funny!)
Primary and Secondary Succession
Primary succession happens in an area where no life has previously existed. Because of this, there is no soil on the groud.
Steps of primary succession:
Initially, there is no life on the rocky ground (A). This could be after a volcanic eruption, or after a glacier melts to expose rock underneath.
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After a while, through wind, rain and animals, seeds for mosses and lichens will enter the area and will start to grow (B).
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As those organisms die and are broken down by decomposers, they will form a thin layer of soil, which can support smaller plants like grasses (C).
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Eventually, there is enough soil (from the previously growing plants) for tree seedlings and shrubs to grow (D).
Steps of primary succession:
Initially, there is no life on the rocky ground (A). This could be after a volcanic eruption, or after a glacier melts to expose rock underneath.
-->
After a while, through wind, rain and animals, seeds for mosses and lichens will enter the area and will start to grow (B).
-->
As those organisms die and are broken down by decomposers, they will form a thin layer of soil, which can support smaller plants like grasses (C).
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Eventually, there is enough soil (from the previously growing plants) for tree seedlings and shrubs to grow (D).
Secondary succession occurs following a disturbance to an ecosystem, such as clearing a forest for farmland. When the farm is abandoned, secondary succession will start.
Steps of secondary succession:
After two years, weeds and wildflowers fill the field (A).
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After five years, pine seedlings and other plants populate the field (B).
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After 30 years, a pine forest has grown up (C).
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After 100 years, a mixed forest of pine, oak and hickory is developing in the field (D).
Steps of secondary succession:
After two years, weeds and wildflowers fill the field (A).
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After five years, pine seedlings and other plants populate the field (B).
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After 30 years, a pine forest has grown up (C).
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After 100 years, a mixed forest of pine, oak and hickory is developing in the field (D).