206 second half

A relationship between two species that provides a fitness benefit to members of one of the species is a ______ interaction.

positive (+) interaction

A relationship that hurts members of one of the species is a ______ interaction.

negative (-) interaction

A relationship that has no effect on the members of either species is a ______ interaction.

0 interaction

There are three basic categories of interactions between species: ______, ______, or +/+ relationships

,–/–; +/–

A +/0 relationship called ______, in which the members of one species benefit, and there is no effect on the fitness of the other species.

commensalism

A -/0 relationship called ______, in which one species is unaffected while the other has a reduction in fitness.

amensalism

The process where evolutionary changes in the traits of one species results in evolutionary changes in the traits of a different species

coevolution

Three key themes in community ecology: species interactions may affect the ______ and ______ of a particular species.

distribution; abundance

Species act as agents of ______ when they interact.

natural selection

In biology, a ______ occurs between predators and prey, between parasites and hosts, and between other types of interacting species

co-evolutionary arms race

The outcome of interactions among species is ______ and ______.

dynamic; conditional

A ______ is a –/– interaction that occurs when individuals use the same limiting resources.

Competition

______ competition occurs among members of the same species and is a major cause of density dependent population growth.

Intraspecific

______ competition is a form of competition involving direct antagonistic interactions between individuals.

Interference competition

Interference competition includes consumptive competition, preemptive competition, overgrowth competition, chemical competition, territorial competition, and ______ competition.

encounter

______ competition occurs when two species consume the same resources.

Consumptive competition

______ competition exists when one species makes space unavailable to another species.

Preemptive competition

______ competition happens when one species grows above another species.

Overgrowth competition

______ competition takes place when one species produces toxins that negatively affect another species.

Chemical competition

______ competition arises when a mobile species protects its feeding or breeding territory against other species.

Territorial competition

______ competition occurs where two species interfere directly for access to specific resources.

Encounter competition

Because competition is a –/– interaction, there is strong natural selection on both species to ______ it.

avoid

An evolutionary change in the traits of species that reduces the amount of niche overlap, also called resource partitioning.

Niche differentiation

______ reduces competition by reducing the amount of niche overlap.

Niche differentiation

Evolutionary changes in the traits of species during the process of niche differentiation.

Character displacement

Competition between species will result in ______ and ______.

niche differentiation; character displacement

The logistic growth equations for two competing species contain both intraspecific competition (-N1) and ______ (-α12N2).

interspecific competition

A coefficient expressing the magnitude of the negative effect of individuals of one species on individuals of a second species.

competition coefficient

______ is the effect of an individual from species 2 on an individual of species 1, relative to the competitive effects of species 1

α12

If α12 > 1, ______ competition is greater than ______ competition

,interspecific; intraspecific

If α12 > 1, ______ competition is greater than ______ competition.

interspecific; intraspecific

Populations will stop growing when ______.

dN/dt = 0

Lines in the graphical representation of the Lotka-Volterra competition model where population growth of the species in competition is zero.

isoclines of zero population growth

Where isoclines cross are ______ points.

equilibrium

Above the isocline, the population is ______; below the isocline, the population is ______.

decreasing; increasing

Above the isoclines for both species, the population sizes will ______.

decrease

Below the isoclines for both species, the populations will ______.

increase

Between the isoclines, the population for N1 will increase and the population for N2 will decrease until N2 is at ______.

0

When the isoclines do not cross, ______ exclusion will occur.

competitive

An ______ equilibrium is a system that, when slightly disturbed from its equilibrium position, moves further away from that position instead of returning to it.

unstable

A ______ equilibrium is a state where a system, when slightly disturbed, returns to its original equilibrium position.

stable

______ is a +/– interaction that occurs when one organism eats another.

Consumption

Consumption increases the fitness of one organism and ______ the fitness of the other.

reduces

There are three major types of consumption: herbivory, predation, and ______.

parasitism

The consumption of plant tissues by herbivores.

Herbivory

The killing and consumption of most or all of another individual

the prey

The consumption of tissues or nutrients from another organism, or host, by a parasite

Parasitism

______ live inside their host, such as tapeworms.

Endoparasites

______ live outside the body of the host, such as ticks, leeches and blood sucking mites.

Ectoparasites

A ______ lives freely as an adult, but is an endoparasite as a larva.

parasitoid

In contrast to parasites, ______ always kill their host.

parasitoids

Prey have adaptations that reduce their chances of becoming consumed by predators, and these are strongly favored by ______.

selection

______ or standing defenses are defenses that are always present.

Constitutive

Constitutive or standing defenses include camouflage, schooling, weaponry, and ______.

mimicry

______ defenses are only present when a predator or consumer is present.

Inducible

Inducible defenses are induced in response to the presence of the ______.

predator

Standing or constitutive defenses include camouflage, schooling and flocking, as well as ______.

weapons

A large group of fish is called a ______.

school

A large group of birds is called a ______.

flock

A large group of mammals is called a ______.

herd

A large group of insects is called a ______.

swarm

A bright warning of dangerous or noxious defenses.

Aposematic coloration

Aposematic coloration is effective on ______ predators, which learn to avoid these patterns.

visual

______ is the close resemblance of one species to another.

Mimicry

Mimicry can protect both ______ and ______ species.

dangerous; harmless

______ Mimicry occurs when harmful species resemble each other.

Müllerian

Müllerian mimicry increases the chances that predators learn to ______ them.

avoid

______ Mimicry occurs when harmless species resemble harmful species.

Batesian

In Batesian mimicry

predators learn to avoid the harmful species

Constitutive defenses can be costly, or ______, to maintain.

expensive

Many organisms have ______ defenses that are only present when the predator or consumer is present, or has been detected.

inducible

Many plants can induce chemical defenses and ______ for defense against herbivores.

toxins

One disadvantage of inducible defenses is that it can take time to “______” the defenses.

turn on

Thicker mussel shells are an inducible defense produced by the presence of ______.

crabs

The plant response to beavers benefits another herbivore, ______ larvae.

beetle

Cottonwood trees cut down by beavers grow new shoots with more defensive compounds that protect them from ______.

beavers

The lecture states that there is no “______” plant defense.

perfect

A ______ interaction is a +/+ interaction.

mutualism

Examples of mutualisms include bacterial nitrogen fixation and plants, as well as ______ associations and plants.

fungi

Organisms involved in mutualisms are not “______” to help each other.

trying

Prey populations typically, but not always, have a much larger intrinsic growth rate, ______, than their predators.

rmax

There is observational and experimental support for the hypothesis that predators play a role in the reduction of ______ population size.

prey

The cumulative evidence indicates that predators can be efficient enough to reduce ______ population sizes.

prey

Hare/Lynx cycles are at least partly driven by density dependent increases in ______.

predation

The structure of a community can change dramatically if a single species of predator or herbivore is removed from or added to a community = ______ species.

keystone

A ______ species has a much greater impact on a community than either its abundance or biomass suggest.

keystone

The sea star ______ is a keystone species in some intertidal areas.

Pisaster

For a keystone predator to increase diversity, it is usually a ______ that prefers to eat whatever prey is most abundant.

generalist

Remember the term “______” when thinking about keystone predators and food chains.

top-down

If otter abundance decreases, the lecture asks what will happen to ______ biomass and total kelp density.

sea urchin

In Gause’s experiments, ________ for both predator and prey provided the optimal situation for recreating predator-prey oscillations.

immigration

In Gause’s experiments, ________ need not be perfect, but provide some degree of escape from predation.

refuges

Without immigration or refuge, predators in Gause’s experiment ________ their food supply.

exhaust

________ experiments used prey mite species that feed on oranges and predators that had to move between oranges.

Huffaker’s Experiments

Huffaker set up 120 oranges separated by discontinuous strips of ________.

petroleum jelly

In Huffaker’s experiments, the predator Typhlodromus had to crawl from one orange to another, whereas the prey ________ could walk or balloon between oranges.,

Eotetranychus

The rate of predation

p

The prickly pear cactus was an ________ species in Australia.

invasive

The South American cactus moth was introduced in the 1920–1930s and drove much of the prickly pears to ________.

extinction

Some prickly pears survived because they were hidden in ________.

refuges