Answer to Question #258290 in Ecology for Max

Question

1. Based on your observations, propose one hypothesis to explain what you see. Consider abiotic factors, intraspecific (i.e. same species), and interspecific (i.e. different species) competition. How would you test your hypothesis? Provide enough explanation to allow any other student in the class to understand your idea and how you would go about testing that idea. Feel free to revisit the old field to expand your observations. (Maximum 1 double-spaced page)

Answer 1

Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources. ... By contrast, interspecific competition occurs when members of different species compete for a shared resource.

Key points:

• In interspecies competition, two species use the same limited resource. Competition has a negative effect on both of the species (-/- interaction).
  
• A species' niche is basically its ecological role, which is defined by the set of conditions, resources, and interactions it needs (or can make use of).
• The competitive exclusion principle says that two species can't coexist if they occupy exactly the same niche (competing for identical resources).
  
• Two species whose niches overlap may evolve by natural selection to have more distinct niches, resulting in resource partitioning.

Competitive exclusion may be avoided if one or both of the competing species evolves to use a different resource, occupy a different area of the habitat, or feed during a different time of day. The result of this kind of evolution is that two similar species use largely non-overlapping resources and thus have different niches. This is called resource partitioning, and it helps the species coexist because there is less direct competition between them.

The anole lizards found on the island of Puerto Rico are a good example of resource partitioning. In this group, natural selection has led to the evolution of different species that make use of different resources. The figure below shows resource partitioning among 11

 species of anole lizards. Each species lives in its own preferred habitat, which is defined by type and height of vegetation (trees, shrubs, cactus, etc.), sunlight, and moisture, among other factors.