Chapter 14: Competition Flashcards
Who was the first to document carnivory in plants?
Charles Darwin
What plants did Darwin study carnivory in?
-Venus Flytrap: inner surface with touch sensitive hairs
-Pitcher Plant: leaves are modified into trap where insects get stuck and tumble into vat of digestive juices
Why do some plants eat animals?
-competition among plants can be intense where soil nutrients are scarce
-adaptation to low-nutrient environments
Brewer (2003)
removed non-carnivorous competitior plants from around pitcher plants and found that pitcher plant growth rates increased greatly
Competition
non-trophic interaction between individuals of two or more species in which all species are negatively affected by their shared use of a resource
Interspecific competition
between members of different species
Intraspecific Competition
between individuals of a single species
Resources
components of the environment that are required by species (food, water, light, space)
Fundamental Niche
the full set of resources, plus other biotic and abiotic requirements of a species
Realized Niche
the restricted set of resources that a species is limited to, due to species interactions
Exploration Competition
-individuals reduce the supply of a resource as they use it
-indirect competition
-Ex: pitcher plants
Interference Competition
-one species directly interferes with the ability of its competitors to use a limiting resource
-direct competition
-Carnivores fighting over animal prey
Interference Competition in Plants
individuals of one species grow on or shade other species, reducing their access to light
Allelopathy
plants of one species release toxins that harm other species
When does belowground competition increase?
Nutrient poor soils
Wilson and Tilman (1993)
studied grass plants that were transplanted into fertilized and unfertilized plots
In Wilson and Tilman (1993), when was below ground competition most intense?
nitrogen limited plots
In Wilson and Tilman (1993), when was above ground competition for light increased?
when light levels are low
Tilman et al. (1981)
2 diatom species showed that when the species were grown together, they competed for silica, and one species drove the other to extinction
Effects of competition are _____ or _____
unequal or asymmetrical (one species is harmed more than the other)
What are the ends of the continuum called that demonstrate how strongly each competitor affects the other?
amensalism: –/0 interactions; individuals of one species are harmed while individuals of the other species are not affected at all
Brown and Davidson (1977)
-exclusion experiments with rodents and ants that eat the same seeds
-when either rodents or ants were removed, the group that remained ate as many seeds as rodents and ants combined
Schoener (1993)
of 390 species studied, 76% showed effects of competition under some conditions, 57% showed effects under all conditions tested
Connell (1983)
competition was important for 50% of 215 species in 72 studies