ECOLOGY Ecosystems and Communities

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ECOLOGYEcosystems and Communities
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I. The Role of Climate

• General Info
• Climate is important in shaping Earths
  ecosystems
• Species are sensitive to climate and can only
  tolerate limited environmental conditions
• Why dont we see banana trees growing in Maine?

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• Weather vs. Climate
• weather day-to-day conditions of Earths
  atmosphere
• climate average, year-after-year conditions of
  temperature and precipitation
• Can be measured over thousands of years
• Caused by heat trapped in atmosphere, latitude,
  winds and ocean currents, precipitation

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Greenhouse Effect

• Greenhouse Effect
• CO2, methane, H2O vapor, and other gases
  naturally trap solar heat in the atmosphere
• Maintains Earths temp
• DRAW Fig 4-1, pg 87

Sunlight
Some heat escapes into space
Greenhouse gases trap some heat
Atmosphere
Earths surface
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Greenhouse Effect Movie
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Intro to Ecosystems Movie
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Abiotic Factors (Non-Living)

• Light
• Ecosystems are driven by solar energy
• Why?
• Temperature
• Temperature affects an organisms metabolism
• Normal range is 0 50C (32 - 122 F)
• Oxygen
• Depth of life in soil affected by oxygen
• Aquatic organisms are limited by oxygen supply in
  water

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• Water
• Water is necessary for life because
• Cells are mostly made of water
• Water dissolves chemicals within cells
• Most of the chemistry in living things involves
  adding or removing water
• Many organisms live in water
• Soil Conditions
• Soils physical makeup (clay, sand, rocks etc.)
  affects organisms
• Animals feed on plants, which are affected by
  soil conditions

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Biotic Factors (Living)

• Food
• Predation
• Interaction where one organism captures and feeds
  on another organism
• Disease
• Competition
• Organisms of the same or different species
  attempt to use an ecological resource in the same
  place at the same time
• For which resources do organisms compete?

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Habitat and Niche

• All of the biotic and abiotic factors make up an
  organism's habitat
• It is where an organism lives
• The way of life or role an organism plays in its
  environment is its niche
• Place in the food web
• Temperature range
• Type of food
• Reproductive season
• No two species can share the same niche
  (competitive exclusion principle)

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Community Interactions

• Competition
• Predation
• Symbiosis - Relationship where two species live
  closely together (3 main types)
• Mutualism - Both species benefit, (ex. honey bee
  and flower, clown fish and sea anemone, shark and
  remora)

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1. Commensalism - One organism benefits, while the
   other is neither helped or harmed (ex. barnacles
   and whale)

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1. Parasitism - One organism lives in or on another
   (host) and harms it (ex. mistletoe, fleas/ticks,
   tapeworm)

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Community Interactions Movie
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Ecological Succession

• Succession
• The process by which an existing community is
  gradually replaced by another one (may take
  hundreds or thousands of years )
• Types of Succession
• Primary Succession - begins where there is no
  living organisms or soil (e.g. lava flows, above
  the timberline or bare rock exposed after
  glaciers melt)

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• Pioneer Organisms - first species to populate
  (e.g. lichens, grasses and mosses help build-up
  the soil
• Lichens are a combination of two organisms
  (fungus and algae) that obtain nutrients through
  photosynthesis and by breaking down rocks

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1. Climax Community - somewhat stable, permanent
   community (e.g. forest, desert, grassland)

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Primary Succession
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• Secondary Succession
• Occurs in an established ecosystem after it is
  destroyed or damaged by a disaster (e.g. fires,
  plowed field, clear cut forest)

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Stages of Succession Movie