Ecosystems

Ecosystem = all biotic (living) and abiotic (nonliving) in an area

Ecosystems are categorized into Biomes (types of ecosystems)

  • classified by dominant vegetation

    • forest, desert, tundra, etc

  • located, geographically, based on the climate (temperature, rainfall, and soil)

  • Intense radiation causes rising air that then cool and drops rain (rises at 0 degrees [equator] and falls at 30 degrees, causes deserts)

  • air can also deflects up off mountains, causing rain shadow effect

    • when it falls, warming hair holds it scant moisture

Succession = series of stages that an ecosystem goes through as a damaged area repairs itself

Damages caused by floods, fires, etc can cause secondary succession

  • secondary succession is when life is still persisting in the soil

  • primary succession is when the ground is left truly barren (like lava flow)

Plants that grow against the glaciers:

  1. mosses and lichens grow first, colonize and grow on bare ground. when they die and decay, their bodies make a rich top soil

  2. dwarf willows grow next

  3. alder trees after, they have acidic leaves, when they drop to the ground, they lower the soil ph. this acid is ideal for…

  4. sitka spruce trees, which are then joined by…

  5. hemlock trees

Early stages may help or hinder the later species come in

Quick reproducers and good migrators (r selected) are able to spread long distances into new territories, they colonize early

  • they are slowly replaced by k selected species, better competitors

  • the chain of events can be broken if it is disturbed regularly

Energy flows through food webs (as one creature eats another)

Detritivores recycle nutrients

  • they are heterotrophs aka consumers

  • autotrophs are producers aka they make their own food

Food webs is made up of many trophic levels

  1. producers

  2. primary consumers or herbivores, eat producers directly

  3. secondary consumers eat primary consumers

  4. tertiary consumers eat secondary consumers

  5. quaternary consumers eat tertiary consumers

Biomass = weight of all life here

90% (roughly) of the energy in 1 trophic level is lost as heat before the next level

Biomagnification = a toxin can concentrate as they move up the food chain