Ecology

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Ecology
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Ecology

• The study of interactions between organisms
  their environment

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Biotic factors

• Living, or once living, organisms in an
  environment

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Abiotic factors

• Non-living parts of an environment
• Air
• Water
• Temperature
• Light
• Soil
• Salinity

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Ecological levels of organization(Smallest to
Largest)

• Organism a single member of a species
• Population a group of interbreeding
  organisms of the same species which live in the
  same habitat
• Competition for food, water, mates, shelter,
  etc due to lack of resources

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Ecological levels of organization(Smallest to
Largest)

• Biological community Interacting populations in
  the same habitat
• Population changes can affect each other in a
  community

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Ecological levels of organization(Smallest to
Largest)

• Ecosystem Plant animal populations interact
  with each other the abiotic factors in an
  environment
• 1.        Terrestrial ecosystems
• 2.       Aquatic ecosystems

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Ecological levels of organization(Smallest to
Largest)

• Biosphere
• All ecosystems
• interacting on
• Earth

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Organisms in ecosystems

• Habitat place an organism lives out its life
• Niche the job or role of an organism in its
  environment
• 1.        How does it meet needs for food?
• 2.       Shelter
• 3.       How and where it survives
• 4.    Reproduction

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Symbiosis (living together)

• A close and permanent relationship between
  organisms of different species
• 3 Types
• Mutualism
• Commensalism
• Parasitism

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Mutualism

• A symbiotic relationship where both species
  benefit e.g.
• 1.        Clown fish and sea anemone
• 2.       Humans and pets
• 3.       Ants Peony flowers
• 4. Lichens algae and a fungus

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British Soldier Lichen
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Commensalism

• A symbiotic relationship in which one species
  benefits and the other is neither helped nor
  harmed
• e.g. Epiphytes and trees (Epiphytes grow in the
  tree habitat, but the tree does not benefit nor
  is it harmed)
• Egret sitting on a rhino
• Barnacle on a whale

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Parasitism

• A symbiotic relationship where one organism
  benefits and the other is harmed e.g.
• 1.       Dog and tick
• 2.       Brown headed cowbird and other
  passerines

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What type of symbiosis?
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Energy flow in an ecosystem
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Energy flow in an ecosystem

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• Producers (Autotrophs) obtain energy from the
  sun via photosynthesis
• Consumers (Heterotrophs) obtain energy by
  eating producers or other consumers

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Types of consumers

• Primary consumer eats producers
• Herbivores eat only producers
• Detritivores- eat detritus (or humus) dead
  decaying organic material
• Secondary consumer eats primary or other
  secondary consumers
• a.   Carnivore eat other consumers
• b.   Omnivore eats both consumers and producers
• c.   Scavenger eat animals that have already
  died
• d.   Decomposers break down dead organisms

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Energy flow in an ecosystem

• Food chain model used by scientists to show the
  flow of energy in an ecosystem
• Food web model used by scientists to show all
  the possible feeding relationships at each
  trophic level in a community

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Energy flow in an ecosystem

• Pyramid of Energy 90 of energy lost in each
  trophic level
• Producers get 100 of energy available
• Primary consumers get 10 of energy available
• Secondary consumers get 1 of energy available
• Tertiary consumers get 0.1 of energy available

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Energy flow in an ecosystem

• Pyramid of Numbers Population size should
  decrease at each higher trophic level
• 3000 Grasses support
• 250 grasshoppers which support
• 25 birds which support
• 1 fox

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Energy flow in an ecosystem

• Pyramid of Biomass total mass of living matter
  at each trophic level
• 100 kg of grain is needed to support
• 10 kg of beef which supports
• 1 kg of human tissue

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Cycles in Nature

• Water
• Carbon
• Nitrogen
• Phosphorus

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Water cycle

• Evaporation
• Transpiration
• Condensation
• Precipitation
• Runoff
• Infiltration

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Carbon Cycle

• Atmospheric CO2 (burning, fuel combustion,
  respiration)
• Death decay result in fossil fuel formation
• Photosynthesis (CO2 conversion into glucose)
• Biomass storage of carbon as coarse woody
  debris

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Carbon Cycle
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Nitrogen Cycle

• Atmospheric Nitrogen fixation by plants,
  bacteria, lightning
• Urine (From protein catabolism)
• Fecal matter fertilizers
• Dead Decaying plant or animal matter
• Nitrogen evaporates into atmosphere from ground
  (Due to denitrifying bacteria)

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Nitrogen Cycle
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Phosphorus Cycle

• Plants obtain phosphorus from soil
• Animals obtain phosphorus by eating plants
• Animals die and decomposers break down phosphorus
  compounds and phosphorus returns to the soil
  (phosphates)

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Phosphorus Cycle