Unit 2: vocabulary Flashcards
age structure
proportion of population members at specific age ranges
biotic potential (rmax)
maximal potential growth rate of a species
birth rate (B)
number of births within a population at a specific point in time
carrying capacity (K)
number of individuals of a species that can be supported by the limited resources of a habitat
clumped dispersion
individuals are closer than expected by chance
cohort
group of the same age that can be followed through time
death rate (D)
number of deaths within a population at a specific point in time
demographic-based population model
modern model of population dynamics incorporating many features of the r- and K-selection theory
demography
statistical study of changes in populations over time
density-dependent regulation
regulation of population that is influenced by population density, such as crowding effects; usually involves biotic factors
density-independent regulation
regulation of populations by factors that operate independent of population density, such as forest fires and volcanic eruptions; usually involves abiotic factors
Emsleyan/Mertensian mimicry
type of mimicry where a harmful species resembles a less harmful one
energy budget
allocation of energy resources for body maintenance, reproduction, and parental care
exponential growth
accelerating growth pattern seen in species under conditions where resources are not limiting
fecundity
potential reproductive capacity of an individual
Ilkka Hanski
studied metapopulation dynamics; found overall balance between sub-population extinctions and re-colonizations
host
organism a parasite lives on
intraspecific competition
competition between members of the same species
iteroparity
life history strategy characterized by multiple reproductive events during the lifetime of a species
J-shaped growth curve
shape of an exponential growth curve
K-selected species
species suited to stable environments that produce a few, relatively large offspring and provide parental care
life history
inherited pattern of resource allocation under the influence of natural selection and other evolutionary forces
life table
table showing the life expectancy of a population member based on its age
logistic growth
leveling off of exponential growth due to limiting resources
mark and recapture
technique used to determine population size in mobile organisms
mortality rate
proportion of population surviving to the beginning of an age interval that die during the age interval
parasite
organism that uses resources from another species, the host
parental care
investment by parents in the production, survival, and development of offspring
population cycle
somewhat regular rise and fall in population size
population density
number of population members divided by the area or volume being measured
population growth rate
number of organisms added in each reproductive generation
population size (N)
number of population members in a habitat at the same time
quadrat
square made of various materials used to determine population size and density in slow moving or stationary organisms
random dispersion
individuals have equal probability of occurring anywhere in area
r-selected species
species suited to changing environments that produce many offspring and provide little or no parental care
S-shaped growth curve
shape of a logistic growth curve
semelparity
life history strategy characterized by a single reproductive event followed by death
species dispersion pattern
(also, species distribution pattern) spatial location of individuals of a given species within a habitat at a particular point in time
survivorship curve
graph of the number of surviving population members versus the relative age of the member
uniform dispersion
relative equal spacing among individuals, maximizes the space between neighbors
zero population growth
steady population size where birth rates and death rates are equal
aggressive display
visual display by a species member to discourage other members of the same species or different species
aggressive mimicry
when a predator mimics something desireable
aposematic coloration
warning coloration used as a defensive mechanism against predation
Batesian mimicry
type of mimicry where a non-harmful species takes on the warning colorations of a harmful one
camouflage
avoid detection by blending in with the background
character displacement
evolutionary changes in traits that makes niche differentiation possible
climax community
final stage of succession, where a stable community is formed by a characteristic assortment of plant and animal species
coevolution
when two interacting species reciprocally influence each other’s adaptations over generations
commensalism
relationship between species wherein one species benefits from the close, prolonged interaction, while the other species neither benefits nor is harmed
community
populations of different species (heterospecific) within an area and the interactions among them
competitive exclusion principle
no two species within a habitat can coexist when they compete for the same resources at the same place and time
distraction display
visual display used to distract predators away from a nesting site
environmental disturbance
change in the environment caused by natural disasters or human activities
food chain
a single path within a food web
food web
the feeding relationships among organisms in a community
foundation species
species which often forms the major structural portion of the habitat
fundamental niche
theoretical range of environmental conditions that a species can tolerate
interspecific competition
competition between species for resources in a shared habitat or environment
keystone species
species whose presence is key to maintaining biodiversity in an ecosystem and to upholding an ecological community’s structure
Müllerian mimicry
type of mimicry where species share warning coloration and all are harmful to predators
mutualism
symbiotic relationship between two species where both species benefit
niche differentiation (resource partitioning)
change in resource use caused by competition over generations
obligate brood parasite
birds that reproduce only by laying eggs in the nests of other species
pioneer species
first species to appear in primary and secondary succession
primary succession
succession on land that previously has had no life
realized niche
portion of the fundamental niche that is actually occupied given limiting factors
relative species abundance
absolute population size of a particular species relative to the population sizes of other species within the community
secondary succession
succession in response to environmental disturbances that move a community away from its equilibrium
species diversity
diversity metric that incorporates both richness and evenness (relative abundance)
species richness
number of different species in a community
symbiosis
close interaction between individuals of different species over an extended period of time that impacts the abundance and distribution of the associating populations
trophic level
the position of an organism in a food chain
adaptive radiation
speciation when one species radiates to form several other species
allopatric speciation
speciation that occurs via geographic separation
allopatry
occurring in different geographic areas
behavioral isolation
type of reproductive isolation that occurs when a specific behavior or lack of one prevents reproduction from taking place
biological species concept
species concept based on reproductive isolation
dispersal
allopatric speciation that occurs when a few members of a species move to a new geographical area
divergent evolution
process by which groups of organisms evolve in diverse directions from a common point
ecological opportunity
the availability of ecologically accessible resources that may by evolutionarily exploited
fusion
upon reconnection, reproductive barriers weaken and the two lineages become one
gametic barrier
prezygotic barrier occurring when closely related individuals of different species mate, but differences in their gamete cells (eggs and sperm) prevent fertilization from taking place
habitat isolation
reproductive isolation resulting when species’ populations move or are moved to a new habitat, taking up residence in a place that no longer overlaps with the same species’ other populations
hybrid
offspring of two closely related individuals, not of the same species
hybrid zone
area where two closely related species continue to interact and reproduce, forming hybrids
monophyletic group (clade)
a group that consists of one ancestor and all of its descendants
morphological innovation
evolution of new morphological trait that allows descendants to exploit new niches
morphological species concept
species concept based on differences in size, shape, or other morphological attributes
phylogenetic species concept
species concept based on identifying smallest sets of monophyletic groups in a phylogeny
phylogeny (phylogenetic tree)
representation of the evolutionary relationships among organisms
postzygotic barrier
reproductive isolation mechanism that occurs AFTER zygote formation
prezygotic barrier
reproductive isolation mechanism that occurs BEFORE zygote formation
reinforcement
continued speciation divergence between two related species due to low fitness of hybrids between them
reproductive isolation
situation that occurs when a species is reproductively independent from other species; behavior, location, or reproductive barriers may cause this to happen
speciation
formation of a new species
species
group of populations that interbreed and produce fertile offspring
species concept
a set of criteria used to define and differentiate species
sympatric speciation
speciation that occurs in the same geographic space
sympatry
occurring in the same geographic area
temporal isolation
differences in breeding schedules that can act as a form of prezygotic barrier leading to reproductive isolation
vicariance
allopatric speciation that occurs when something in the environment separates organisms of the same species into separate groups
