Biodiversity

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Biodiversity

• Equilibrium
• Succession
• Biodiversity
• Species at risk
• Human Impact

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Equilibrium

• When biotic and abiotic features remain constant
  over time
• On a large scale, healthy natural ecosystems are
  in a state of equilibrium
• E.g. biomes maintain characteristics
• On a small scale, ecosystems are in a constant
  state of change
• E.g. forest fire, disease outbreak

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Ecological Succession

• Process of establishing and replacing a community
  following a disturbance
• Primary succession occurs on soil or bare rock
  where no life previously existed
• E.g. following a volcanic eruption, sandy shores
  of coastline
• Secondary succession follows a disturbance that
  disrupts but does not destroy the community
• E.g. regrowth after forest fire

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ecosystems/imagesetc/ecological_succession.jpg
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Pattern

• Coloniser
• Lichen, moss
• Pioneer Community
• Small, hardy plants (e.g. grass)
• Shrubs small trees
• Climax community
• Forest (large trees)
• reached equilibrium

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Benefits of Succession

• Helps ecosystem maintain long-term sustainability

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Biodiversity
.

• the number and variety of species in an ecosystem
• important for maintaining a stable population
• Species richness measurement of species numbers

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Biodiversity

• Case The Irish potato famine resulted in great
  hunger because the potato was such an important
  crop.
• Today, people in developed countries have a lot
  of food choices so they are able to meet their
  nutritional needs.

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Analysis Question
Ecosystems with HIGH biodiversity Ecosystems with LOW biodiversity

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Analysis Question
Ecosystems with HIGH biodiversity Ecosystems with LOW biodiversity
Rain forests and oceans, coral reef both have warm temperatures, regular, precipitation, abundant food supply In general, ecosystems closer to the equator are more rich. (little to no pollution or disturbance) The Arctic tundra and the desert both have extreme temperatures and short growing seasons for plants at the first trophic level In general, ecosystems with extreme physical conditions are less rich
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Ecotone

• Organisms often move from one ecosystem to
  another.
• An ecotone is a transition area between two
  ecosystems that includes members of the community
  of both ecosystems.
• Ecotones often have a lot of biodiversity.

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Monoculture

• A monoculture is an ecosystem in which there is
  only one plant
• often created by humans in agriculture
• Example a wheat field

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Problems with Monocultures

• More susceptible to pest infestation than natural
  ecosystems
• Invaders do not have to search for food and can
  multiply uncontrollably.
• All it takes is one invader who is resistant to
  pesticides and the whole monoculture ecosystem
  can be destroyed by the invader.

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Monoculture
Advantages of monocultures Disadvantages of monocultures

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Monoculture
Advantages of monocultures Disadvantages of monocultures
increased food production can adjust farming conditions in the field to maximize production (irrigation, fertilization) easier to harvest if all the plants are in one area decreased biodiversity and damages the environment pests can multiply in the absence of their natural predators
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Extinction

• A natural process
• Usually caused by catastrophic event (e.g.
  asteroid, volcano)
• Human activity has increased rate of extinction

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Species at Risk

• When a population's size declines below a
  critical level, the species will not longer be
  able to fill it ecological niche
• COSEWIC Committee on the Status of Endangered
  Wildlife in Canada
• Responsible for categorizing species into at-risk
  categories
• RENEW Recovery of Nationally Endangered Wildlife
• Responsible for preparing action plans to ensure
  recovery of endangered or threatened species

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Species at Risk classifications
Classification Definition Example
Extinct Species no longer exists Passenger pigeon
Extirpated Species no longer exists in the wild in a specific area but live elsewhere Atlantic walrus
Endangered Species in imminent danger of going extinct or becoming extirpated Barn owl
Threatened Species likely to become endangered if current trends and conditions continue Humpback whale
Special concern Species may become threatened or endangered because of a combination of factors Polar bear
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Artificial ecosystem Natural ecosystem
Definition An ecosystem planned or maintained by humans. Members of this ecosystem are free to interact with the physical and chemical environment.
Examples Parks, gardens, farms, schoolyard Lakes, rivers, deserts, forests, meadows