Chapter 41: Species Interactions Flashcards
What effects can interactions in a community have on the species involved?
they can help, harm or have no effect
What characterize biological communities
diversity and trophic structure
What does disturbance influence?
species diversity and composition
What does biogeographic factors affect?
community diversity
How are pathogens structured?
locally and globally
What is a biological community?
a group of populations of different species living close enough to interact
What are interspecific interactions?
The interactions between individuals of different species living in the same community
What type of interspecific interaction is competition?
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What type of interspecific interaction is predation?
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What type of interspecific interaction is herbivory?
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What type of interspecific interaction is parasitism?
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What type of interspecific interaction is mutualism?
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What type of interspecific interaction is commensalism?
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When does interspecific competition occur?
individuals of different species compete for a resource that limits the survival and reproduction of each species (food space, mates)
What is competitive exclusion?
when two species are vying for a resource, eventually the one with the slight reproductive advantage will eliminate the other
What is an ecological niche?
the sum of biotic and abiotic resources that an organism uses its environment.
What is an organism’s niche?
its ecological role - how it fits into an ecosystem
When can two species cannot coexist permanently in a community?
if their niches are identical
What is resource partitioning?
the differentiation of niches that enables similar species to coexist in a community
What is a fundamental niche?
the niche potentially occupied by that species
What is a realized niche?
the portion of its fundamental niche that the species actually occupies
What is character displacement?
the tendency for characteristics to diverge more in geographically overlapping areas than in geographic isolated areas?
What is predation?
the interaction between species in which one species eats another
What is the consumer called in predation?
the predator
What is the one eaten called in predation?
the prey
What is cryptic coloration?
camouflage that makes prey difficult to see
What is aposematic coloration?
animals that have effective chemical defenses often have bright colors that act as a warning to others
What is batesian mimicry?
when one harmless species mimics a harmful species to which it is not closely related
What is mullein mimicry?
when two or more harmful species resemble each other and get the added advantage by having greater # of individuals
What is herbivory?
the interaction where an organism eats parts of a plant or algae.
Give two ways in which plants defend against predators
Chemical toxins, spines and thornes
What is symbiosis?
the interaction in which individuals of two or more species live in direct contact with one another
What is parasitism?
the symbiotic relationship where one organism, the parasite derives its nourishment from the host which is harmed in the process
What are endoparasites?
parasites that live inside of their hosts
What are ectoparasites?
parasites that live and feed on the outside of their host
What do parasites affect in their host population?
survival, reproduction and density
What is mutualism?
a symbiotic relationship that benefits both species
What is commensalism?
a symbiotic relationship that benefits one of the species but neither harms nor helps the other
What is species diversity?
the variety of different kinds of organisms that make up the community
What is species richness?
the number of different species in the community
What is relative abundance?
the proportion each species represent of all of the individuals
What is biomass?
the total mass of all organisms in a habitat
What is trophic structure?
the feeding relationships that exist between organisms in a community. Each organism occupies a trophic level based on their main food source
What is a food chain?
the transfer of food energy up the trophic levels
Who are on the bottom of the food chain?
primary producers
Who eat primary producers?
primary consumers
Who eat primary producers?
secondary consumers
Who eat secondary consumers?
tertiary consumers
Who eat tertiary consumers?
quaternary consumers
What is a food web
a diagram of the trophic relationships of a community (linking multiple food chains together)
What does the food web show?
the flow of energy and nutrients through an ecosystem through a variety of possible paths
What are dominant species?
species that are the most abundant or that collectively have the highest biomass
What are keystone species
species who exert strong control on community structure by their pivotal ecological niches
What is stability?
a community tendency to reach and maintain a relatively constant composition of species
What does a disturbance do?
changes a community by removing organisms from it or altering resource availability
What does the immediate disturbance hypothesis state?
that moderate levels of disturbance foster greater species diversity than do high or low levels of disturbance
What is ecological succession?
transitions in species composition in a certain area over ecological time
What is primary succession?
when succession begins in a virtually lifeless area where soil has not yet formed
What is a pioneer species?
the first species to colonize a new habit
What is secondary succession?
succession that occurs when an existing community has been cleared by a disturbance that leaves the soil intat
Most parries experience regular fires, typically every few years. If these disturbances were relatively modest, how would the species diversity of a prairie likely be affected if no burning occurred for 100 years? Why?
low level of disturbance ==> diversity would be expected to decline as competitively dominant species gain sufficient time to exclude less competitive species
How does latitude effect diversity of a community?
plant and animal life are generally more abundant and diverse in the tropics
How does are effect community diversity?
if all other factors are held equal, the larger the geographic area of a community, the more species it has in it
why do islands provide excellent opportunities for studying the biogeographic factors that affect the species diversity of communities?
because of their isolation and limited size
What two factors determine the number of species on an island?
the rate at which new species immigrate to the island and the rate at which new species become extinct
What two features of an island effect the rates?
size and distance from the mainland
What is the island equilibrium model?
small islands generally have lower immigration rates than large islands and higher extinction rates; the farther an island is from the mainland, the higher the rate of extinction
How would you expect the richness of birds on islands to compare with the richness of snakes and lizards? Why?
Birds disperse to islands more often than snakes/lizards so they should have greater richness
