BIOL 3301 exam 3

What is a population

a group of interacting organisms of the same species living in the same place at the same time

What four general factors can bind a population together

geography, behavior, resources, and convenience

What is meant by a populations biotic structure

it includes the number of individuals, density, and age classes within the population

What aspects are included in a populations spatial structure

geographic distribution, habitat arrangement, dispersion of individuals, and movement patterns

According to Hutchinson, a niche is an n dimensional hyper volume where n equates to what

the number of the environmental factors important to the survival and reproduction of a species

What is a limiting resource in the context of population ecology

a resource that establishes the maximum population size

Distinguish between a fundamental niche and a realized niche

fundamental niche is the full hypervolume of conditions a species can tolerate, while the realized niche is the portion it actually occupies due to interactions like competition

The geographic are in which a species occurs is known as its ___

geographic range

What factors can constrain a species geographic range

geographic barriers, distance, physical features, and competition

How does climate indirectly influence species distributions

by affecting food production, water supply, habitat and the incidence of parasites, pathogens, and competitors

A species with a geographically widespread distribution is called a ___ species

ubiquitous or cosmopolitan

What is an endemic species

a species with a geographically restricted distribution, often due to specialized habitat requirements

Define population density

the number of individuals per unit area

What is the difference between population abundance and population density

abundance is the actual total number of organisms, while density is the number of organisms per unit area

What is dispersion in population context

the spacing of individuals with respect to one another within the geographic range of a population

What is clustered dispersion ( also called clumped or aggregated)

individuals are aggregated in discrete groups

What factors typically lead to a clustered dispersion patter

heterogeneous resource distribution, mutual attraction between individuals, and weak dispersal tendencies

An evenly spaced dispersion pattern is one in which each individual maintains a ___ between itself and its neighbors

uniform distance

What factors often cause an evenly spaced (uniform) dispersion pattern

aggressive behaviors, competition for limited but homogeneous resources, and strong dispersal tendencies

What is a random dispersion pattern

position of each indibidual is independent of the position of other individuals

Under what conditions does a random dispersion pattern typically occur

when resources are randomly distributed and not limiting and there is a lack of strong social or interactive forces

What is the key difference between dispersal and migration

dispersal is a one way movement away from a habitat, while migration is an annual or seasonal round trip movement

What are the primary drivers of migration

local climate, seasons, food availability, and variations in the life cycle

What factors can drive dispersal of individuals

reproduction, resource availability, competition, and change environmental conditions

What is dispersal limitation in conservation biology

the absence of a population from suitable habitat because of barriers to dispersal

A strip of favorable habitat located between two large patches of habitat that facilitates dispersal is know as a ___

habitat corridor

How is a population growth rate calculated

it is the number of new individuals produced minus the number of individuals that die

What is the intrinsinc growth rate of a population

the highest possible per capita growth rate for a population under ideal conditions

Geometric growth is an appropriate model for populations with ___ generations and ___ reproduction

non overlapping; discrete

Exponential growth is an appropriate model for populations with ___ generations and ____ reproduction and death

overlapping; continuous

What is the key characteristic of density dependent factors that limit population growth

their intensity is influenced by the density of the population

Provide three examples of density dependent factors

disease, resource competition, and predation

What defines a density independent factor in population regulation

it controls population size with no relation to the populations density

Provide three examples of density independent factor

natural disastesr, temperature, and precipitation

The concept that regulation and density dependence imply competition among individuals for limited resources is called ___ competition

intraspecific

What is the name for the S shaped population growth curve that accounts for environmental limits

logistic population growth

What does the carrying capacity of an environment represent

the maximum number of individuals of a population that the environment can support

What is the self thining curve in plant populations

it shows how decreases in population density over time lead to increase in the mass of each individual in the population

What is the allee affect

a density dependent mechanism that reduces birthrate and survival when a population is at a very low density

Name two potential causes of the allee affect

difficulty in finding a mate and breakdown of social structures like pack hunting

What is the difference between a cohort life table and a statistic life table

a cohort life table follows individuals born at the same time, while a static life table records the age at death of individuals at a single point in time

What are the three ecologically important age classes a population can be divided into

prereproductive, reproductive, and postreproductive

If a populations net reproductive rate is greater than 1.0 what is happening to the population

the population is growing

What does a net reproductive rate of less than 1.0 indicate about a population

the population is declining

For a species with non overlapping generatgions the geometric rate of increase is equal to what other demographic parameter

the nret reproductive rate

What is competition, in an ecological sense?

Any use or defense of a resource by one individual that reduces the availability of that resource to other individuals.

Differentiate between intraspecific and interspecific competition.

Intraspecific competition is among individuals of the same species, while interspecific competition is among individuals of different species.

What is Liebig’s law of the minimum?

A law stating that a population increases until the supply of the most limiting resource prevents it from increasing further.

What is the Competitive Exclusion Principle, as formulated by Gause?

Two species competing for the same limiting resource cannot coexist indefinitely; one will eventually exclude the other.

Tansley’s experiments with bedstraw (Galium spp.) suggested that interspecific competition restricts the _ of each species.

realized niche

The Lotka Volterra model predicts coexistence of two species when, for both species, ___competition is weaker than ___ competition.

interspecific; intraspecific

What is allelopathy

A type of interference competition where organisms use chemicals to harm their competitors.

What is character displacement?

The divergence in characteristics of two similar species where their ranges overlap, caused by the selective effects of competition.

What is the expected evolutionary result of strong interspecific competition on the niches of the competing species?

directional selection for reduced niche overlap

What is the difference between an exotic species and an invasive species?

An exotic species is found outside its normal range, while an invasive species is an exotic species that spreads rapidly and has negative effects.

The introduction of the moth Cactoblastis cactorum to Australia to control the prickly pear cactus is an example of what practice?

biological control

What two main factors are believed to drive the population cycles of snowshoe hares and lynx?

Fluctuations in the food supply for hares and predation by lynx and other predators.

What did Gause’s experiments with Paramecium and Didinium demonstrate about the requirements for stable predator prey cycling

Stable cycling requires both refuges for the prey and immigration.

What is the Red Queen Hypothesis as it applies to predator prey relationships?

It suggests that predators and prey are in a constant co-evolutionary race, where each must continually evolve just to maintain its current fitness level relative to the other.

What is aposematic coloration?

Warning colors, often combined with chemical defenses, that advertise an organism’s unpalatability or toxicity to predators.

What is Batesian mimicry?

A form of mimicry where a harmless species evolves to imitate the warning signals of a harmful or noxious species.

What is Mullerian mimicry?

A form of mimicry where two or more noxious or well

How does ‘predator satiation’ work as a prey defense?

Prey reduce their individual probability of being eaten by living and emerging in extremely dense populations, overwhelming the feeding capacity of predators.

What is ‘masting’ in trees, and how does it relate to predator satiation?

Masting is the synchronous, widespread production of seeds and fruit, which satiates seed predators and allows more seeds to survive.

How can large body size function as a refuge from predation?

If predators ignore individuals above a certain size, growing large provides protection, as the large prey may be less profitable to pursue.