Interactions and Coevolution Flashcards
Define competition.
an interaction between individuals in which each is harmed by their shared use of a resource that limits their ability to grow, survive, or reproduce.
Define interspecific competition. Define intraspecific competition. Provide an example of each.
interspecific - competition between individuals from different species (i.e. lions and cheetahs both prey on zebras)
intraspecific - competition between individuals from the same species (i.e. sexual selection between male peacocks)
Provide two examples of how competition and resource ability affect one another.
1) density and type of diatoms affect silica concentration because diatoms need silica for their cell walls
2) light availability affect competition intensity of plants
Define indirect competition. Define direct competition. Provide an example of each.
indirect - exploitation - species compete indirectly through their mutual effects on the availability of shared resources - include herbivory, parasitism, and predation (i.e. kuzu plants shade neighboring plants)
direct - interference - species compete directly by performing antagonistic actions that interfere with the ability of their competitors to use a shared resource that they both require (i.e. large aphids defend cottonwood leaves by ejecting smaller aphids from the better feeding sites)
Provide a local and regional example of how competition can influence distribution.
local - different barnacle species occupy separate spaces within intertidal zones
regional - different chipmunk species occupy separate spaces within different mountain ranges
Define the competitive exclusion principle. Provide an example.
two species that use a limiting resource in the same way that cannot coexist indefinitely, meaning that if a species fulfills a very similar ecological niche - the physical and biological conditions that a species needs to grow, survive, and reproduce - to a superior competitor, than it may be driven to extinction (i.e. grey squirrels replaced red squirrels in Britain because they were better fitted to the environmental conditions)
Define resource partitioning. Provide an example.
when different species in a community use limiting resources in different ways, meaning the two competitors can coexist (i.e. red and green cyanobacteria absorb different colors of light, meaning that they can coexist in white light)
Define character displacement.
aka niche differentiation - process in which competition causes the phenotypes of a competing species to evolve to become more different over time, causing the competing species to become more different where they live together than where they live apart (i.e. different species of fish feed at different depths)
Define predator. List the four different predation tactic. Provide an example of each.
a type of exploitative interaction that involves killing and eating other animals
search predators - sharks and grey wolves actively hunt
sit and wait predators - chameleons change their colors to match their surroundings and project their tongues to capture prey; scorpionfish hide in the shadows of rocks and wait for prey to swim by
generalists - bobcats and coyotes eat a wide variety of small mammals, birds, and reptiles
specialists - the canada lynx only feeds on snowshoe hares; venus flytraps can only eat insects and arachnids
List the four ways that prey meets the selective pressures of predators. Provide an example of each.
physical features -clams have hard shells to protect soft bodies from predators; sea urchins have sharp spines to deter predators; electric eels produce an electric current; sea cucumbers are soft so that they can squeeze through small openings to evade predators
toxins - stingrays; cone snails; poison dart frogs; squids
mimicry - moth species may mimic dead leaves, or other larger species to intimidate predators; harmless kingsnakes have the same coloring as deadly coral snakes to avoid predation
behavioral defenses - squids use jet propulsion to evade predators; possums play dead to deter predators
Describe how predation affects the distribution and abundance of prey.
as prey abundance increases, predator abundance increases due to increased food availability. as predator abundance increases, prey abundance declines, resulting in a feedback loop of predator abundance declining. prey distribution will decrease in areas of high predator distribution.
Describe how predation affects ecological communities.
trophic cascade - predators control distribution and abundance of prey, meaning they indirectly regulate lower species in the food chain. they can also disperse rich nutrients and seeds from foraging.
Define herbivore. Provide an example of each type of herbivore.
a type of exploitative competition that involves only consuming plants
most herbivores specialize on either plant parts (i.e. several species of bat only feed on the fruit of a plant) or plant species (i.e. koalas only eat eucalyptus leaves)
Describe how plants meet the selective pressures of herbivory. Provide examples of each.
avoidance - some plants grow in spatial refuges physically inaccessible to or hidden from herbivores, such as cliff ledges
tolerance - some plants may experience an increase in reproductive or photosynthetic rates when subjected to light damage from herbivory
defense - structural or chemical defenses such as thorns, trichomes (thick hairs that hinder movement, limit consumption, and prevent eggs)
Describe how herbivores meet the selective pressures of plant defenses. Provide examples of each.
structural adaptations - i.e. low-crowned teeth specialized for grinding foliage and seeds; mandibles in insects to cut and tear plant material
chemical adaptations - salivary enzymes that reduce the degree of defense by a host plant - i.e. aphids
behavioral adaptations - i.e. winter moths feed on oak leaves early in the season to maximize protein and nutrients
