45 terms

apes chapter 6 vocab

composed of all individuals that belong to the same species and live in a given area at a particular time
incorporates all of the populations of organisms within a given area
population density
the number of individuals per unit area (or volume, in the case of aquatic organisms) at a given time
population size
the total number of individuals within a defined area at a given time
population distribution
a description of how individuals are distributed with respect to one another
sex ratio
the ratio of males to females
age structure
a description of how many individuals fit into particular age categories
density dependent factors
influence an individual's probability of survival and reproduction in a manner that depends on the size of the population
limiting resources
a resource that a population cannot live without and which occurs in quantities lower than the population would require to increase in size
carrying capacity
the limit of the environment
density independent factors
have the same effect on an individual's probability of survival and amount of reproduction at any population size
growth rate
is the number of offspring an individual can produce in a given time period, minus the deaths of the individual or its offspring during the same time period
intrinsic growth rate
maximum potential for growth under ideal conditions with unlimited resources available
exponential growth model
r(t) = r0 e^kt
j shaped curve
is the shape of the graph when the exponential growth model is graphed
logistic growth model
describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment
s shaped curve
is the shape of the graph when the logistic growth model is graphed
if there is less food available in the spring than needed to feed the offspring, the population will experience an overshoot by becoming larger than the spring carrying capacity
die off
population crash
k selected species
species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age
r selected species
species that reproduce early in their life span and produce large numbers of usually small and short-lived offspring in a short period
survivorship curves
it shows the likelihood of survival at different ages throughout the lifetime of the organism
strip of natural habitat that connects two adjacent nature preserves to allow migration of organisms from one place to another
a collection of populations that have regular or intermittent gene flow between geographically separate unit
community ecology
the study of how interactions between species affect community structure and organization
interaction among organisms that vie for the same resource in an ecosystem
competitive exclusion principle
two species competing for the same limiting resource cannot coexist
resource partitioning
the division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species
an interaction in which one organism captures and feeds on another organism
true predators
kill prey and consume most of it when they kill
an organism that eats only plants
an organism that lives in or on another organism, deriving nourishment at the expense of its host, usually without killing it
parasites that cause disease in their host
organisms that lay eggs inside other organisms
a relationship between two species in which both species benefit
a relationship between two organisms of different species where one benefits and the other is neither harmed nor benefited
is the relationship of two species that live in close association with each other
keystone species
a species that influences the survival of many other species in an ecosystem
predator mediated competition
competition in which a predator is instrumental in reducing the abundance of a superior competitor, allowing inferior competitors to persist
ecosystem engineers
a keystone species that creates or maintains habitat for other species
ecological succession
the predictable replacement of one group of species by another group of species over time
primary succession
occurs on surfaces that are initially devoid of soil
secondary succession
occurs in areas that have been disturbed but have not lost their soil
pioneer species
ability to colonize new areas rapidly and grow well in full sunshine
theory of island biogeography
he number of species found on an island is determined by a balance between two factors: the immigration rate (of species new to the island) from other inhabited areas and the extinction rate (of species established on the island). The model predicts that at some point the rates of immigration and extinction will reach an equilibrium point that determines the island's average number of different species (species diversity)