Ecology

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Ecology
Organisms
Organisms
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Niche

• It is an organisms role in the community. It
  includes
• what it eats
• What eats it
• What and how much resources it uses
• Can you think of an example?

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Limits on population size

• The maximum number of individuals of a species
  that an area can support is called carrying
  capacity
• Limiting factors are factors that limit a
  populations size
• Factors can be abiotic or biotic

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Population growth
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Limiting factors

• Examples of abiotic include
• Oxygen in a pond,
• amount of sunlight
• Temperature
• Examples of biotic factors include
• Predators
• Competition

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Figure 53.10 Examples of terrestrial and marine
food chains
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Figure 53.11 An antarctic marine food web
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Other feeding relationships

• Decomposers break down dead plants and animals.
• This recycles the materials
• Scavengers are consumers that eat dead organisms
• Parasites attack living organisms

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Figure 54.2 Fungi decomposing a log
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Figure 54.11 An idealized pyramid of net
production
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• Materials are recycled but energy is NOT
• Ecosystems need a constant source of energy from
  the sun.

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Figure 54.17 The carbon cycle
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Biodiversity

• Is the measure of how many different species
  there are in an area
• Ecosystems that have a high biodiversity are more
  stable
• It is valuable to humans because it can be a
  source of medicine.
• What other benefits are there?
• Name a human activity that can lead to the loss
  of biodiversity

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Loss of Biodiversity

• Direct Harvesting
• Habitat destruction
• Deforestation
• Imported Species

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Water Pollution

• Sewage and animal wastes add nutrients to the
  water
• This causes algae to grow more and die more
• Decomposers suck oxygen out of the water
• If too much oxygen is removed, the fish begin to
  die

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Toxic Wastes

• Chemicals that are added to lakes and rivers can
  kill off many kinds of organisms
• An example is DDT
• Biological control

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Burning fossil fuels

• Burning oil and coal releases CO2 and sulfur into
  the air
• Sulfur in the air will lead to acid rain that can
  damage or kill plants and animals
• Can cause some lakes to be so acidic that nothing
  can live there
• CO2 is a greenhouse gas and can lead to global
  warming
• Ice caps can melt causing a rise in sea level and
  loss of coastline

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Ozone Depletion

• Ozone is found in the upper atmosphere
• It absorbs much of the harmful radiation from the
  sun
• Depletion of the ozone will allow more harmful
  radiation to hit the Earth
• This can lead to higher mutation and cancer rates.