Topic 11: Interspecific Competition Flashcards
Competition is often seen as what?
Competition is often seen as the major driving force behind the divergence and specialization of species.
Interspecific competition involves?
Interspecific competition involves two or more species
Interspecific competition can be categorized into different forms. What is an example of indirect interaction?
exploitation/scramble:
- consumption of a shared resource but no direct contact.
- pre-emption by occupation preventing others from establishing.
- overgrowth by growing and shading out others.
Interspecific competition can be categorized into different forms. What is an example of direct interaction?
Interference/contest:
- encounters that involves direct conflict over a resource.
- chemical interference by inhibiting or killing another species.
- territorial control by defending space.
What is the competitive exclusion principle? What happens if one species has even a slight advantage?
complete competitors cannot coexist. if one species has any advantage, the other, weaker species will go to extinction.
How can environmental factors influence competition, and what kind of factor is this?
pH, humidity, salinity, or temperature. these abiotic factors can very sharply across the landscape. species perform better under certain abiotic conditions and poorly under others.
this is a non-resource factor.
Give an example of how environmental factors can help two species co-exist even though the require similar resources.
Juncus and wheat grass; wheat grass should theoretically out compete the juncus grass bc the wheat grass is bigger. BUT the juncus grows in more alkaline conditions (where there is more salt) and the wheat grass grows best in less alkaline places (less salt the higher you go in the marsh). so they occupy different places and thus can co-exist.
Explain how temporal variations allow for competitive advantages to change over time. What does this prevent from occurring?
variation in the environment over time (seasons/decades) changes which species will be the more successful competitor. as a result no species reaches sufficient density to displace its competition and both co exist.
Territoriality in plants can take the form of?
allelopathy. toxic compounds released from one species inhibits the growth of others.
How does environmental gradients allow for species to co-exist?
some portion of the gradient will be optimal for a particular species but not for others. results in one species having competitive advantages under one set of conditions but not under another.
Species can co-exist by? what does this reduce?
resource specialization. reduces competition.
What is the definition of niche?
the sum of a species habitat requirements.
What does it mean for a species niche breadth being broad or narrow?
broad species have a wide range of niche conditions they can occupy.
narrow species are specialized for a much narrower brand of conditions.
What does the breadth of a niche depend on?
breadth of a niche depends on the dimensions considered.
What happens to competition as we consider more niche dimensions?
the more dimensions we consider, the less likely that species will be “complete competition” leading to competitive exclusion.
basically reduces competition.
