SL Content Statements

• C4.1.10

  A community as all of the interacting organisms in an ecosystem
  

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  Communities comprise all the populations in an area including plants, animals, fungi and bacteria.
  

• C4.1.11

  Herbivory, predation, interspecific competition, mutualism, parasitism and pathogenicity as categories of interspecific relationship within communities
  

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  Include each type of ecological interaction using at least one example.
  

• C4.1.12

  Mutualism as an interspecific relationship that benefits both species
  

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  Include these examples: root nodules in Fabaceae (legume family), mycorrhizae in Orchidaceae (orchid family) and zooxanthellae in hard corals. In each case include the benefits to both organisms.
  

• C4.1.13

  Resource competition between endemic and invasive species

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  Choose one local example to illustrate competitive advantage over endemic species in resource acquisition as the basis for an introduced species becoming invasive.
  

• C4.1.14

  Tests for interspecific competition

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  Interspecific competition is indicated but not proven if one species is more successful in the absence of another. Students should appreciate the range of possible approaches to research: laboratory experiments, field observations by random sampling and field manipulation by removal of one species.
  NOS: Students should recognize that hypotheses can be tested by both experiments and observations and should understand the difference between them.
  

• C4.1.15

  Use of the chi-squared test for association between two species

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  AOS: Students should be able to apply chi-squared tests on the presence/absence of two species in several sampling sites, exploring the differences or similarities in distribution. This may provide evidence for interspecific competition.
  

• C4.1.17

  Top-down and bottom-up control of populations in communities

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  Students should understand that both of these types of control are possible, but one or the other is likely to be dominant in a community.
  

• C4.1.18

  Allelopathy and secretion of antibiotics

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  These two processes are similar in that a chemical substance is released into the environment to deter potential competitors. Include one specific example of each—where possible, choose a local example.