Flashcards in chapter 11 Deck (39)
the pattern of density and spacing of individuals in a population.
the range of abiotic conditions (e.g., temperature, humidity, salinity) under which a species can persist.
: the range of abiotic & biotic conditions under which a species can persist
measure of the total area covered by a population (e.g., temperature and drought define the range of sugar maple).
creates geographic ranges that are composed of small patches of suitable habitat.
Small-scale variation in the EVR
The Lewis’ monkeyflower lives at high elevations, whereas the scarlet monkeyflower lives at low elevations.
When planted outside their natural elevations, the two species grew poorly and experienced lower survival.
what does this suggest?
plants are limited by unsuitable environmental conditions.
general rule about population growth
populations can grow larger in more suitable habitats.
what does understanding the realized niche of a species help with
species aids in species conservation and can help to limit the spread of invasive species.
the process of determining the suitable habitat conditions for a species.
Ecological niche modeling
range of ecological conditions that are predicted to be suitable for a species (differs from the realized niche, which describes conditions in which a species currently exists).
what do researchers use to predict potential geographic range of a species when few individuals exist?
researchers can use historic distributions of species.
Temperature change can cause
a shift in the geographic range of species.
) What is the difference between pop. distribution and population dispersion?
Population dispersion is the spacing of individuals with respect to one another within a population.
species that live in a single, often isolated, location.
species with very large geographic ranges that can span several continents.
total # of individuals in a pop. that exist w/in a defined area (e.g., total number of lizards on a mountain).
The total abundance of a population provides a measure of
whether a population is thriving or on the brink of extinction.
the number of individuals per unit area or volume; calculated by dividing abundance by area
where does the largest density of indiviiduals typically occur?
near the center of a population’s geographic range.
What mechanisms could cause evenly spaced distributions of individuals w/in pops.?
E. territorial animals
the spacing of individuals with respect to one another within the geographic range of a population.
when individuals are aggregated in discrete groups (e.g., social groups or clustering around resources).
when each individual maintains a uniform distance between itself and its neighbors (e.g., defended territories, croplands).
Evenly spaced dispersion
when the position of each individual is independent of other individuals; not common due to non-random environmental heterogeneity
the movement of individuals from one area to another.
the seasonal movement of individuals back and forth between habitats.
counting every individual in a population.
surveys that define the boundaries of an area or volume and then count all of the individuals in the space.
Area- and volume-based surveys
surveys that count the number of individuals observed as one moves along a line.