Bio Ch. 54

occurs when species compete for a resource in short supply (-/- interaction)

mimic dangerous or distasteful prey

prevent a predator from noticing potential prey

plant toxins, skunk scent

sea urchin spines, rosebush thorns

a behavioral adaptation in birds and is analogous to schooling or herding in other species; reduce the chance that any individual prey animal will be eaten by a predator

one species benefits by harming another; +/- interaction

one species benefits; the other is unaffected +/0

both species benefit +/+

natural selection favors phenotypes at one extreme of the distribution. Phenotypes al the other extreme are selected against. Directional selection causes the distribution of traits to shift toward the phenotype that is favored.

natural selection favors phenotypes at both extremes of the distribution. Intermediate phenotypes are selected against. Disruptive skeleton causes the distribution of traits to shift toward the two extremes, producing a bimodal (two-peak) distribution

natural selection favors intermediate phenotypes. Phenotypes at both extremes are selected against. Stabilizing selection causes intermediate phenotypes to become more common in a population

describes a situation where the traits of sympatric populations overlap less than the traits of allopatric populations

ecological niche

batesian mimicry

producers

detritivore

secondary consumer

primary consumer

tertiary consumer

its food source

a surface exposed by a retreating glacier. This surface lacks any life and is thus a starting point for primary succession

the island's size and distance fro m the mainland

is an assemblage of populations of various species living close enough for potential interaction

relationships between species in a community

the survival and reproduction of each species and the effects can be summarized as positive, negative or no effect

that two species competing for the same limiting resources cannot coexist in the same place

the total of a species' use of biotic and abiotic resources

can coexist in a community if there are one or more significant differences in their niches

is differentiation of ecological niches, enabling similar species to coexist in a community

the niche potentially occupied by that species

the niche actually occupied by that species

may differ from its realized niche

tendency for characteristics to be more divergent in symmetric populations of two species than in allopatric populations of the two same two species

refers to an interaction in which one species, the predator, kills and eats the other, the prey

claws, teeth, fangs, stingers, and poision

behavioral defenses, morphological and physiological defense adaptations,

adaptations of prey; animal turns the same color as surrounding

adaptations of prey; warning coloration ex. poison dart frog

a palatable or harmless species mimics an unpalatable or harmful model (harmless species mimics a harmful one)

two or more unpalatable species resemble each other

refers to an interaction in which an herbivore eats parts of a plant or alga

evolution of plant mechanical and chemical defenses and adaptations by herbivores

is a relationship where two or more species live in direct and intimate contact with one another

one organism, the parasite, derives nourishment from another organism, its host which is harmed in the process

parasite that live within the body of their host

parasites that live on the external surface of a host

involving a number of hosts

is an interspecific interaction that benefits both species

obligate or facultative

where one species cannot survive without the other

where both species can survive alone

one species benefits and the other is neither harmed nor helped

to document in nature because any close association likely affects both species

in which one species has positive effect on other species without direct and intimate contact

are species diversity and feeding relationships

a community is the variety of organisms that make up the community

species richness and relative abundance

the number of different species in the community

the proportion each species represents of all individuals in the community (relative abundance)

diversity can be compared using a diversity index H= -(pAlnPa + pBlnpB + pclnpC+...)

more productive and more stable in their productivity; better able to withstand and recover from environmental stresses; more resistant to invasive species, organisms that become outside their native range

is the feeding relationships between organisms in a community

link trophic levels from producers to top carnivores

plant, phytoplankton

herbivore, zooplankton

carnivore (ex. mouse, fish)

carnivore (ex. snake, larger fish)

carnivore (ex. bird, whale)

a branching food chain with complex trophic interactions

one trophic level

grouping species with similar trophic relationships into broad functional groups; isolating a portion of a community that interacts very little with the rest of the community

only a few links long

that length is limited by inefficient energy transfer

proposes that long food chains are less stable than short ones

dominant species, keystone species, ecosystem engineers

are those that are most abundant or have the highest biomass

powerful control over the occurrence and distribution of other species

exert strong control on a community by their ecological roles, or niches

are not necessarily abundant in a community

their role as a keystone species in intertidal communities

cause physical changes in the environment that affect community structure

organization proposes a unidirectional influence from lower to higher trophic levels

also called the trophic cascade model, proposes that control comes from the trophic level above

can help restore polluted communities

view that communities are in a state of equilibrium

suggested that species in a climax community function as a super organism

which describes communities as constantly changing after being buffeted by disturbances

suggests that moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance

slow growing species

dominant species to exclude less competitive species

is the sequence of community and ecosystem changes after a disturbance

occurs when no soil exists when succession begins

begins in an area where soil remains after a disturbance

soil nitrogen is low; nitrogen increases as succession proceeds

biological communities world wide

usually reduces species diversity

key factors that affect a community's species diversity

great in the tropics and generally declines along an equatorial-polar gradient

richness are probably evolutionary history and climate

are likely the primary cause of the latitudinal gradient in biodiversity

is evaporation of water from soil plus transpiration of water from plants

quantifies the idea that, all other factors being equal, a larger geographic area has more species

island size, distance from the mainland, immigration, and extinction

maintains that species richness on an ecological island levels off at dynamic equilibrium point

which include disease-causing microorganisms, viruses, viroids, and prions

community structure quickly and extensively

dramatic effects on communities

pathogens around the world at unprecedented rates

have been transferred from other animals to humans

a vector

zoonotic

for a pathogen can help prevent disease

species have positive effects on the survival and reproduction of other species without the intimate contact of a symbiosis