Interactions within communities by dffhrtcv3


									Interactions within communities
• Within an ecosystem, populations of
  different species interact in what is called a
  community (_______________________
• __________________________________)
• Some organisms within the community
  cannot survive independently but rely on
  other organisms.
            Ecological Niches
• A niche includes characteristics of an organism,
  interaction with _________ and _____________
  resources in its environment.
• If habitat s an organism’s “address” then it’s
  ______ is it’s “occupation”
• Ex. African lions niche food, habitat,
  reproduction, climate and behaviour
• Niche: carnivore + environment.
           Fundamental Niche

• Fundamental niche (theoretical): the biological
  characteristics of the ________and the
  ________________ that individuals in the
  population are theoretically capable of using under
  _______ conditions.
• In reality the lion faces interspecific competition
  Thus, ___________________ (a portion of its
  fundamental niche)
• Interactions WITHIN a species
  (______________) and
• BETWEEN individuals of different species
  (________________) in a ______________
  have important influences on population
  dynamics of individual species.

Interaction                Effect on Population
Competition                Interaction may be detrimental to one or both species.
Predation                  Interaction is beneficial to one species and usually lethal
                           to the other
              Parasitism   Interaction is beneficial to one species, and harmful but
Symbiosis                  not usually fatal to the other
              Mutualism    Interaction is beneficial to both species
              Commensalism Interaction is beneficial to one species and the other is
     Interspecific Competition

• Between ________________________
• Restricts ________________________
     • 1) Interference competition: interspecific
       competition that involves aggression between
       individuals of different species who fight over the
       same resources.
     • 2) Exploitative competition: interspecific
       competition that involves consumption of shared
       resources by individuals of different species, where
       consumption by one species may limit resource
       availability to other species.
• The strongest competition occurs when niches
• Results from interspecific competition:
      • weaker competitor could decline in numbers
      • one species could change behaviour so it’s able to survive
        using different resources
      • Individuals in one population could migrate.
• One way individuals of species occupying the
  same niche can avoid or reduce competition for
  similar resources is by resource partitioning
• Resource partitioning: avoidance of, or reduction
  in, competition for similar resources by
  individuals of different species occupying
  different non overlapping ecological niches.
• It is an example of interspecific interaction in
  which the population density of both species
  fluctuate. Predator population increases while the
  population density of the other species – the prey-
  declines. Predator lags behind.
• Can have significant effect on both the predator
  and prey population sizes.
• Display a cyclic pattern between the two
  population sizes.
            Defense Mechanisms
• Predator- diverse defense mechanisms that plant
  and animal species have evolved through repeated
  encounters with predators over time.
• Plants:____________________ defenses: thorns,
  hooks, spikes, needles.
• _________________ defenses: eg. Mustard family
  of plants contains oils that make them toxic.
 Example of interesting defenses:
• ___________________ can sometimes affect competition.
• Ex. Passionflowers vines produce toxic chemicals to
  protect it. Heliconius butterfly is able to feed on the vines
  because it has enzymes that break down the chemicals.
• They also lay their eggs on the leaves of the flower- the
  eggs are bright yellow so other butterflies avoid them it
  and reduces intraspecific competition.
• The plants have coevolved yellow nectaries that resemble
  the eggs to discourage Heloconius from laying eggs on the
• ________________ defense mechanisms include
  as hiding,
• ___________ defense mechanism might be
• Active defense mechanisms are more costly in
  energy then passive.
• __________ defenses include alarm calling
• Camouflage is also used by prey to help blend into
  the background (passive defence mechanism)
• Defense colouration can help show predators that
  they are poisonous or distasteful
• Mimicking – gaining an advantage
by resembling a distasteful species
• Batesian
• Mullerian
• Named after the scientists that discovered
• Batesian
• A ________________ or harmless species mimics
  an unpalatable or harmful one (most often
  observed in moths and butterflies) Monarch
• Mullerian
• Different species resemble one another
• All are poisonous or dangerous so predators are
  warned by the colouration.
• Evolved similar colouring to minimize predation.
• This term means “living together”. Individuals of
  two different species live in close, usually
  physical, contact. At least one of the individuals
  benefits from the association.
Three types of symbiotic relationship:
• _______________
• _______________
• _______________
• Mutualism: A symbiotic relationship in which
  _______________________; as neither is harmed,
  it is categorized as a +/+ relationship.
• Obligatory Mutualism: neither species could
  survive without the other.
• Commensalism: a symbiotic relationship in
  which one organism benefits and the other
  organism is unaffected; This is a __________
• Parasitism: one organism (the parasite) benefits
  at the expense of the host. The host is often
  harmed but usually not killed; [ +/-]
• Microparasites: microscopic in size . ex.
  ______________ protozoan that causes malaria.
• Endoparasites: live and feed _________ the
  host’s body. Ex. A tapeworm (also a
• Ectoparasite: Live and feed on the ________
  surface of the host, such as lice.
• Pg 691 (Investigating Predator- Prey
  Cycling 14.4.1)
• Symbiosis worksheet

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