APES UNIT 3: POPULATIONS

Density Independent Factor

A factor that has the same effect on a individual's probability of survival and reproduction at any population size

random, uniform, clumped

Three types of population distribution

Density Dependent Factor

A factor that influences an individuals probability of survival and reproduction in a manner that depends on the size of the population (i.e. predation, disease, food supply)

exponential growth models

occurs when populations are not limited by resources. (J-curve)

logistical growth model

occurs when populations fluctuate at a carrying capacity established by a limiting resource and initially experience large growth but then level off at K

survivorship curve

survival patterns of different species. Type I (K-selective) care for their young, Type II constant death rate throughout life, and type III (r-selective) low survival of the young.

K-selected species

A species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity (TYPE I)

r-selected species

A species with a high intrinsic growth rate that causes the population to overshoot and quickly die off (TYPE III)

Population size

The total number of individuals of one species within a defined area at a given time

Population density

The number of individuals per unit area at a given time

Population distribution

How individuals are distributed with respect to one another

age structure diagram

how many individuals fit into age categories. (in a model)

Growth Rate

The number of offspring an individual can produce in a given period of time, minus the deaths of the individual or offspring during the same period

Metapopulations

A group of spatially distinct populations that are connected by occasional movements of individuals between the populations

Competition

The struggle of individuals to obtain a limiting resource

Resource partitioning

Where species divide up a resource based on difference in the species behavior or morphology-this can reduce competition

Predation

The use of one species as a resource by another species

Parasites

Type of predation when species live on or in the organism they consume

Parasitoids

Type of predation when species lay eggs inside other organisms

Mutualism

A type of interspecific interaction where both species benefit

Commensalism

A type of relationship in which one species benefits but the other is neither helped nor hurt

Keystone Species

a species that plays a role in its community that is far more important that its relative abundance might suggest

Primary Succession

Replacement of species, one after another, which occurs on surfaces that are initially devoid of soil. Starts with moss and lichens on the exposed rock and it it progresses to shrubs and plants and eventually restores ecosystem.

Secondary Succession

Replacement of species, one after another, occurs in areas that have been disturbed but have not lost their soil

Community Ecology

The study of the interactions between species in a habitat

Competitive exclusion principle

two species competing for the same limited resource cannot coexist. This explains why resource partitioning takes place so that both can survive

Interspecific Competition

When two species compete over one limited resource

Intraspecific Competition

When two individuals within the same species compete over one limited resource

Factors that determine species richness

Latitude (distance from equator), Time (older the habitat, the higher SR), Habitat size (larger=greater)

Theory of Island Biogeography

Explains that both habitat size and distance from coloring species determine species richness; larger habitats contain more species, as do habitats which are closer to colonizers

innovation and technology

How does the human population not have a food deficit?

growth rate equation

CBR-CDR/10

doubling time for a population equation

70/growth rate

Demography

The study of human populations and population trends

Total Fertility Rate (TFR)

estimate of the average number of children each woman will bear in her lifetime

Replacement level fertility (RLF)

the total fertility rate required to offset the average number of deaths in a population and for the current population size to remain stable

Developed Countries

Countries with high levels of industrialization and income

Developing Countries

Countries with relatively low levels of industrialization and income

Life Expectancy

The average number of years that an infant born in a particular year in a particular country can be expected to live, given the current average life span and death rate of that country

Infant Mortality Rate

Number of deaths of children under the age of one per 1000 births

Child Mortality Rate

Number of deaths of children under the age of five per 1000 births

Demographic Transition

The theory that as a country moves from a subsistence economy to and industrialized one, it undergoes a predictable shift in population growth

Family Planning

Regulating the number or spacing of children through the use of birth control

IPAT equation

environmental Impact=Population x Affluence x Technology

Gross Domestic Product (GDP)

The sum total of the value of all the goods and services produced in a nation

population momentum

The propensity for a growing population to continue growing even through fertility is declining because of their young age distribution

Crude Birth Rate (CBR)

The total number of live births in a year for every 1,000 people alive in the society.

Crude Death Rate (CDR)

The total number of deaths in a year for every 1,000 people alive in the society.

carrying capacity

Largest number of individuals of a population that a environment can support

limiting resource

a resource that a population cannot live without and which occurs in quantities lower than the population would require to increase in size

Community

All the different populations that live together in an area

symbiotic

mutually beneficial; supporting one another's life

pioneer species

first species to populate an area during succession

Pathogens

organisms that cause disease