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Biology 3.4 Describe animal behaviour and plant responses in relation to environmental factors

Subject content

Make sure you have up-to-date course notes. Use them, and if you haven't got them, see your teacher.

The environmental factors involved in animal behaviour and plant responses are abiotic (that is, they relate to non-living factors) or biotic (that is, they relate to living factors). The relationship of environmental factors to behaviour or response may be in terms of the process involved, or the adaptive significance.

Responses to the abiotic environment may include:

• orientation responses:
  
  • tropisms – phototropism (response to light stimulus) and the role of auxin (hormone), geotropisms/gravitropism (response to gravity), thigmotropism (the response to touch), hydrotropism (response to water), and chemotropism (response to a chemical stimulus)

    Tropisms may be positive or negative responses.

  • nastic responses
  • taxes – types of taxes include: chemotaxis (chemicals), geotaxis (gravity), thermotaxis (heat), hydrotaxis(water), thigmotaxis (touch)

    Each type of taxis response is also to be described as negative (taxis is away from the stimulus) or positive (taxis towards the stimulus). For example, when an organism moves bodily towards a chemical stimulus, such as a pheromone, it is said to be positively chemotaxic. Read about animals that release or detect pheromones.

  • kineses – orthokinesis (the organism’s speed of movement), klinokinesis (the organism’s rate of turning)
  • homing
  • migration
    Migration is an extraordinary behavioural adaptation that many species exhibit, and which contributes to the survival of a species. For example, to gain the benefits of staying in a perpetual summer, the New Zealand godwit or kuaka makes the longest non-stop bird migration known in the world from New Zealand to Alaska. Read about how they store enough fuel for this extraordinary flight.
• timing responses:
  
  • annual
  • daily – diurnal, nocturnal, and crepuscular
  • lunar
  • tidal
  • biological clocks – exogenous rhythms, endogenous rhythms, and understanding actograms

Responses to the biotic environment may include:

• interspecific relationships:
  
  • predation
  • parasitism
  • mutualism
  • commensalism
  • competition for resources
  Predator and prey are often tied together in many ways. The populations of predator and prey are related. If the predator population is low, the numbers of the prey species will increase. Most predator species will reproduce in larger numbers if food is abundant. As the numbers of the predator species increase, the prey population begins to decline. This process means the 'less fit' individuals are weeded out, helping the gene pool of both the predator and the prey to stay strong.
• intraspecific relationships:
  
  • territoriality
  • cooperative interactions – social behaviour, clumping
  • reproductive behaviours – parental care, courtship, pair-bonding, monogamy, polygyny, polyandry, polygynandry, and polygamous
  • hierarchical behaviour
  • competition for resources.

Supplementary material for level 3 biology – this link provides useful information for all of level 3 biology and for this standard; pages 3–13 are useful to help plan your study.
http://www.tki.org.nz/r/ncea/bio3_supportmaterial_15feb06.doc

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