Chap.6 Flashcards
Definitions
The individuals that belong to the same species and live in a given area at a particular time
Population
All of the populations of organisms within a given area
Community
population ecology
The study of factors that cause populations to increase or decrease
The total number of individuals within a defined area at a given time.
Population size (N)
The number of individuals per unit area at a given time
Population density
A description of how individuals are distributed with respect to one another
Population distribution
The ratio of males to females in a population
Sex ratio
A description of how many individuals fit into particular age categories in a population
Age structure
A resource that a population cannot live without and that occurs in quantities lower than the population would require to increase in size
Limiting resource
A factor that influences an individual’s probability of survival and reproduction in a manner that depends on the size of the population
Density-dependent factor
The limit of how many individuals in a population the environment can sustain
Carrying capacity (K)
A factor that has the same effect on an individual’s probability of survival and the amount of reproduction at any population size
Density-independent factor
Mathematical equations that can be used to predict populaiton size at any moment in time
Population growth models
The number of offspring an individual can produce in a given time period, minus the deaths of the individual or ti’s offspring during the same period.
Population growth rate
The maximum potential for growth of a population under ideal conditions with unlimited resources
Intrinsic growth rate
A growth odel that estimates a population’s future size after a period of time based on the intrinsic growth rate and the number of reproducing individuals currently in the population
Exponential growth model
The curve of the exponential growth model when graphed
J-shaped curve
A growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment
Logistic growth model
The shape of the logistic growth model when graphed
S-shaped curve
When a populatio nbecomes larger than the environment’s carrying capacity
Overshoot
A rapid decline in a population due to death
Die-off
A species with a low intrinsic growth rate that causes the populaiton to increase sloly until it reaches carrying capacity
k-selected species
A species that has a high intrinsic groth rate, which often leads to populaiton overshoots and die-offs
r-selected species
A graph that represents the distinct patterns of species survival as a function of age
Survivorship curve
A pattern of survival over time in which there is high survival throughout most of the life span, but then individuals start to die in large numbers as the approach old age.
Type I survivorship curve
A pattern of survival over time in which there is a relatively constant decline in survivoship throughout most of the life span
Type II survivorship curve
A pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood
Type III survivorship curve
Stips of natural habitat that connect populations
corridor
A group of spatially distinct populations that are connected by occasional movements of individuals between them
metapopulation
When individuals with similar genotypes- typically relatives-breed with each other and produce offspring that have an impaired abitlity to survive and reproduce
Inbreeding depression
The study of interactions between species
Community ecology
The relationship between two species that live in close association with each other
Symbiotic relationship
The struggle of individuals to obtain a shared limiting resource
Competition
The principle stating that tow species competing for the same limiting resource cannot coexist
Competitive exclusion principle
When two species divide a resource based on differences in their behavior of morphology
resource partitioning
An interaction in which one animal typically kills and consumes another animal
Predation
A specialized type of predator that lays eggs inside other organisms - refered to as it’s host
Parasitoid
Parasitism
An interaction in which one organism lives on or in another organism
A parasite that cuases disease in it’s host
pathogen
An interaction in which an animal consumes a producer
Herbivory
An interaction between two species that increases the chances of survival or reproduction for both species
Mutualism
A relationship between species in which one species benefits and the other species is neither harmed nor helped.
Commensalism
A species that is not very abundant but has large effects on an ecological community
Keystone species
A keystone species that creates or maintains habitat for other species
Ecosystem engineer
The predictable replacement of one group of species by another group of species over time
Ecological succession
Ecological succession occuring on surfaces that are initially devoid of soil
Primary succession
The succession of plant life that occurs in areas that have been disturbed but have not lost their soil
Secondary succession
A species that can colonize new areas rapidly and grow well in full sunshine
pioneer species
historically described as the final stage of succession
climax community
