Ecology

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Ecology
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What is Ecology?

• Study of interactions among
• Organisms (Living-Living)
• Organisms and their environment
  (Living-Nonliving)

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Species- a group of similar organisms that can
breed and produce fertile offspring.
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3-2 Ecological Levels of Organization
Section 3-1
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Levels of Organization

• Individual- one organism (living)
• Ex a moose

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Levels of Organization

• Population- groups of individuals that belong to
  the same species and live in the same area.
  (living-living same species)
• Ex many moose

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Levels of Organization

• Community- groups of different populations (more
  than one population or different groups of
  species)
• Ex many groups of moose, beavers, trees, grass
  (all living)

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Levels of Organization

• Ecosystem- all organisms in a particular area
  along with the nonliving. (living and nonliving)
• Ex many groups of moose, beavers, trees, grass,
  rocks, water, mountains

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Levels of Organization

• Biome- group of ecosystems that have the same
  climate and similar dominant communities
• Biomes tropical rain forest, tropical dry
  forest, tropical savannah, temperate grassland,
  desert, temperate woodland and shrub land,
  temperate forest, northwestern coniferous forest,
  boreal forest (taiga), tundra, mountains and ice
  caps

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Levels of Organization

• Biosphere- all of the planet where life exists,
  includes land, water, and, air
• Life extends 8 km up and 11 km below the surface

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What shapes an ecosystem?

• Biotic factors- biological (living) influences on
  ecosystem
• Ex. Interactions between organisms, predation,
  symbiosis, etc.

• Abiotic factors- nonliving influences on
  ecosystems
• Ex. Temperature, precipitation, nutrient
  availability, soil type, sunlight.

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Biotic- anything living
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Abiotic- anything non-living
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What are the roles of organisms in an ecosystem?

• Habitat- an area where an organism lives
• Niche- full range of physical and biological
  conditions in which an organism lives and the way
  in which the organism uses those conditions.
• Includes where in the food chain it is, and where
  an organism feeds
• Habitat is like an address in an ecosystem and a
  niche is like the job in an ecosystem.

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In an ecosystem, organisms need to be able to
obtain energy.

• Producers- make their own food
• Consumers- get energy from consuming producers

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Producers

• Capture energy from sunlight or chemicals and use
  the energy to produce food.
• Producers are autotrophs- they make food from
  their environment

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Autotrophs convert food to energy in 2 ways

• Get energy from the sun by photosynthesis
• Get energy without light by chemosynthesis

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Consumers

• Consumers are heterotrophs- get energy from other
  organisms
• Types of Consumers
• Herbivores- eat only plants
• Carnivores- eat animals
• Omnivores- eat both plants and animals
• Detritivores (decomposers)- eat dead matter
  (plants and animals)

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Feeding Relationships

• Energy flows through an ecosystem in one
  direction from
• 1. the sun or inorganic compounds
• 2. To autotrophs (producers)
• 3. To heterotrophs (consumers)
• Decomposers get energy from decomposing dead
  organisms

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Food Chain- a series of steps in which organisms
transfer energy by eating or being eaten.

• Food Web- A network of feeding relationships.
• (More realistic that a food chain)

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Trophic levels

• Each step in a food chain or a food web is called
  a trophic level.
• Producers are the first trophic level
• Consumers are the second, third, or higher
  trophic level
• Each trophic level depends on the one below for
  energy

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Flow of Energy

• Only part of the energy stored in one level can
  be passed to the next
• Most energy is consumed for life processes
  (respiration, movement, etc., and heat is given
  off)

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Energy Pyramid (contd)

• Only 10 of the energy available within one
  trophic level is transferred to organisms in the
  next trophic level
• Less than 1 is actually used by organisms on
  Earth

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Biomass Pyramid

• Biomass- the total amount of living tissue within
  a given trophic level.
• A biomass pyramid represents the amount of
  potential food available for each trophic level
  in an ecosystem.

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Biomass Pyramid
50 grams of lion tissue
500 grams of giraffe
5000 grams of greenery
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Pyramid of Numbers

• Ecological pyramids can also be based on the
  numbers of individual organisms at each trophic
  level.
• The pyramid of numbers shows the relative number
  of individual organisms at each trophic level.
• Because each trophic level harvests only about
  1/10th of the energy from the level below, it can
  support only about 1/10th the amount of living
  tissue.

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