Community Interactions

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Community Interactions
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Community Interactions

• Powerfully affect an ecosystem
• Include
• Competition
• Predation
• Symbiosis

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Competition

• When organisms of the same or different species
  attempt to use an ecological resource at the same
  place and the same time
• Resource? any necessity to life
• Plants and animals compete
• Winner and losers

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Rules, rules, rules

• Fundamental rule in ecology
• Competitive Exclusion Principle
• No two species can occupy the same niche in the
  same habitat and the same time
• Prevents competition

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Predation

• Interaction where an organism captures and feeds
  on another organism
• Predator
• Organism that does the killing and eating
• Prey
• Organism that is being killed and eaten (victim)

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Symbiosis

• Any relationship where two species live closely
  together
• Symbiosis literally means living together
• 3 main types
• Parasitism
• Mutualism
• commensalism

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What type of relationship is this?

• Who is helping who?

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Mutualism

• Both species benefit from the relationship
• A Happy couple
• Flowers and bees
• Flowers need bees for pollination, bees need
  flowers nectar

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What type of relation ship is going on here?

• Who is helping who?

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Commensalism

• One member of the relationship benefits while the
  other is neither harmed nor helped
• One-sided
• Food or shelter
• Barnacles on whale

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Ants and aphids
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What type of interaction is going on here?
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Parasitism

• One organism lives on or inside another organism
  and harms it
• Parasite obtains all or part of its nutrients
  from the other organism
• Host
• Organism that is harmed in relation ship the one
  that provides the nutrients to the parasite
• Parasite
• Organism that gets its nutrients from the host
• Do they want to kill their host?
• No, because they need themthey will weaken or
  hurt the host in some way

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Recap

• What are the three types of interactions in a
  community?
• Competition
• Predation
• Symbiosis
• What types do we have?
• Mutualism
• Commensalism
• Parasitism

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Ecological Succession

• Do all ecosystems stay the same all the time?
• What are some things that cause changes to
  ecosystems?
• Natural and unnatural
• Quickly and slowly

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• Ecosystems are constantly changing in response to
  human and natural disturbances.
• As an ecosystem changes, older habitants die out
  and new organisms move in, causing more change

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Ecological Succession

• Series of predictable changes that occur in a
  community over time
• Physical environment
• Natural disturbance
• Human disturbance

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Primary Succession

• Succession on land that occurs on surfaces where
  no soil exists
• Volcanic eruptions
• Glaciers melting

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Stages of Primary Succession

• Start with no soil, just ash and rock
• First species to populate this area
• pioneer species
• For example, pioneer species on volcanic rock are
  lichens (LY-kunz)
• Lichens? made up of fungus and algae that can
  grow on bare rock
• When lichens die, they for organic material that
  becomes soilnow plants can grow

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Secondary Succession

• Succession following a disturbance that destroys
  a community without destroying the soil
• Natural
• hurricane
• fires
• Human disturbances
• Farming
• Forest clearing

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Succession in Marine Ecosystems

• Deep and dark
• Can succession happen?
• 1987 dead whale off of California
• Unique community of organisms living in remains
• Represents stage in succession in an otherwise
  stable, deep-sea ecosystem
• Whale-fall community

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Whale-Fall Succession

• Begins when large whale dies
• Sinks to barren ocean floor
• Scavengers and decomposers flock to carcass , our
  first community
• Amphipods
• Hagfish
• sharks
• After a year, most tissues have been eaten
• Now, second small community of organisms live
  here
• Body is decomposing, releasing nutrients into the
  water
• Small fishes
• Crabs
• Snails
• worms
• Only skeleton remains
• Third community moves in
• Heterotrophic bacteria
• Decompose oil in bones? release of chemical
  compounds
• Who uses these chemical compounds?
• Chemoosynthetic autotrophs

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Study Chemical reactions, enzymes, and Chapters 3
and 4
Teacher,