What Happens When Organisms Compete

deadlysilence's version from 2010-11-29 00:52


Question Answer
When will competition occur among organisms of different species?When they attempt to use the same limited resource.
What is the difference between direct and indirect competition?Direct competition: fighting. Indirect competition: use same resource.
Explain 3 reasons why competition is negative for the organisms involved.Injury, wasted energy, organisms may obtain less of a resource than they need.
Explain how competition can lead to competitive exclusion.Better competitors force weaker ones out of the community.
When will competitive exclusion lead to extinction?The inferior competitor cannot survive elsewhere.
How many species are known to have gone extinct in North America since the Pilgrims landed in 1620?500
Approximately how many species are currently going extinct due to competitive exclusion from humans every year, and how does this rate compare to the extinction rate when dinosaurs disappeared? 10,000-40,000; Higher than the extinction rate
What percentage of all species on the planet may become extinct within your lifetime?60%
Competition among individuals of the same species usually occurs over what two limited resources?Food, mates.
Discuss 3 ways in which organisms may reduce competition for food within their species.Live alone, dominance hierarchy. Eat different things.
Discuss one way in which organisms may reduce competition for mates.Natural selection favors physical characteristics that make it less dangerous for mates.


Question Answer
Which more commonly leads to extinction: competition or predation?Competition
How can predation lead to cycles of prey and predator abundance?As prey abundance cycles, predator abundance also cycles.
How can predators prevent extinction?Predators prevent superior competitors from taking over.
What is a keystone species?Organisms that have a strong influence over community structure.


Question Answer
competitionan interaction between organisms within a community in which all species are negatively affected. Competition occurs when organisms attempt to use the same limited resource.
direct competitioncompetition in which organisms directly fight with one another over resources
indirect competitioncompetition in which organisms don't fight, but simply exploit the same resource. If the resource is limited, none of the organisms may obtain enough of it.
competitive exclusiona common outcome of competition. It occurs when one species is a better competitor than another. The stronger competitor will eventually drive the weaker one out of the community. If there is no suitable habitat for the weaker species elsewhere, it will become extinct.
extinctionthe loss of a species from a particular area, often caused by competitive exclusion. Extinction may be local (and thus, potentially reversible), or planet-wide (and thus, permanent).
dominance hierarchyA method that many social organisms to reduce competition for food (and sometimes mates). Every individual has a rank within its society, and this indicates when every individual is entitled to eat from shared food sources. Ranks are determined among animals in many ways, including size, age, gender, personality, and often relatedness to other individuals of particular ranks.
biodiversitythe number of different species in an area
keystone speciesan organism that has a strong influence over community structure. If that species disappears, the structure of the community will change drastically. Predators are often keystone species.

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