Ch 54 Flashcards
ecological niche
distinctive lifestyle and role of an organism in a community, takes into account all abiotic and biotic aspects, for example, an organism’s habitat is one parameter used to describe the niche; the totality of an organism’s adaptations, its use of resources, and the lifestyle to which it is fitted in its community, how an organism uses materials in its environment as well as how it interacts with other organisms; it’s a lifestyle–are they predator or prey? it’s their role as well as who they interact with, and the things it needs in its environment to survive
fundamental niche
potential ecological niche for an organism; all the area that an organism could potentially use as an area for survival and reproduction
realized niche
niche an organism actually occupies; the habitat an animal actually lives in
limiting resources
environmental factors that restrict a realized niche; the resources that limit the fundamental niche to the realized niche
competition
two or more individuals attempting to use the same resource
intraspecific competition
among individuals within a population of the same species
interspecific competition
between different species
Red Grouse contest with intraspecific competition vs. Isle Royal Moose scramble with intraspecific competition
Red Grouse: low population, non-aggressive territorial high population, dominance hierarchies (a contest where the winner is ensured enough resources); Moose: peak and crash as overgraze occurs
competitive exclusion principle
two species cannot occupy the same niche in the same community for an indefinite period, one species is excluded by another as a result of competition; the concept that no two species with identical living requirements can occupy the same niche indefinitely
resource partitioning
some species reduce competition by resource partitioning; resource partitioning is the reduction of competition for environmental resources such as food that occurs among coexisting species as a result of each species’ niche differing from the others in one or more ways
character displacement
the tendency for two similar species to diverge (become more different) in areas where their ranges overlap; this reduces interspecific competition
predation
consumption of one species (the prey) by another (the predator)
What are some predator strategies?
pursuit, ambush, and parasitoidism (when a parent lays eggs (or young) inside of prey and the young will eat its way out of that prey)
What are some defenses used against predators?
mechanical defenses, associating in groups, cryptic coloration (crypsis: colors or markings that help some organisms hide from predators by blending in to their physical surroundings), warning coloration: coloration that warns predators of a mechanical defense, and Mullerian mimicry
Mullerian mimicry
the resemblance of dangerous, unpalatable, or poisonous species to another so that potential predators recognize them more easily
Batesian mimicry
the resemblance of a harmless or palatable species to one that is dangerous, unpalatable, or poisonous so that predators are more likely to avoid them
coevolution
refers to reciprocal evolutionary adaptations of two interacting species, when one species evolves it exerts selective pressure on the other to evolve to continue the interaction; the reciprocal adaptation of two or more species that occurs as a result of their close interactions over a long period
symbiosis
an intimate relationship between two or more organisms of different species
mutualism
in ecology, a symbiotic relationship in which both partners benefit from the association; both partners benefit
commensalism
a type of symbiosis in which one organism benefits and the other one is neither harmed nor helped; one species benefits, the other is unharmed but does not gain from the relationship
parasitism
a symbiotic relationship in which one member (the parasite) benefits and the other (the host) is adversely affected; on species benefits, the other is harmed; parasites that cause disease or death are referred to as pathogens
keynote species
a species whose presence in an ecosystem largely determines the species composition and functioning of that ecosystem; example: kangaroo rats in the Chihuahuan desert largely determine the structure of the plant community by their preference for large seeds
dominant species
in a community, a species that as a result of its large biomass or abundance exerts a major influence on the distribution of populations of other species; affect the community because they are so common
species richness
number of species within a community
species diversity
relative importance of each species within a community
Island biogeography
the larger an island is, the greater the number of species that can be present, but the distance the island is from a mainland also plays an important role, the further the island is from a source habitat, the less likely it is that a new species will show up and survive
What are some factors that affect species richness?
high stress communities support fewer species than low stress areas (ex: polluted vs. unpolluted areas) and species diversity is greater in ecotones; another stress is not being able to mix with other species that are similar to yours, also, interaction with humans
ecotone
a transitional area between distinct communities: the edge effect
succession
the process of community development over time, which involves species in one stage being replaced by different species
primary succession
the change in species composition over time in a habitat that was not previously inhabited by organisms, no soil exists when primary succession begins, bare rock surfaces, such as recently formed volcanic lava and rock scraped clean by glaciers, are examples of sites where primary succession might take place; occurs in an area not previously inhabited
secondary succession
the change in species composition that takes place after some disturbance removes the existing vegetation, soil is already present at these sites, abandoned agricultural fields or open areas produced by forest fires are common examples of sites where secondary succession occurs; occurs where there is a pre-existing community and a well-formed soil
intermediate disturbance hypothesis
in community ecology, the idea that species richness is greatest at moderate levels of disturbance, which create a mosaic of habitat patches at different stages of succession; disturbance affects succession and species richness; species richness is greatest at moderate levels of disturbance
