unit 3 vocab: populations

Specialist species

Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food. EX: Panda

Generalist species

species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. EX: cockroaches, raccoon, rats, humans

Exponential growth

Population growth that grows slowly at first, then more and more rapidly. It has an abundance of resources for an ever-increasing population. (J-shaped curve)

Logistic growth

Population growth in which a population begins with a period of slow growth followed by a brief period of exponential growth before leveling off at a stable size (S-shaped curve)

K-selected species (K-strategists)

Species that tend to be large, have few offspring, invest lots of time and energy caring for offspring, take a long time to mature, and have long lifespans. (most mammals)

r-selected species (r-strategists)

Species that tend to be relatively small, have many offspring, invest minimal energy and time caring for offspring, mature early, have short lifespans. (most reptiles, amphibians, and insects)

Biotic potential (r) (intrinsic growth rate)

The maximum rate at which a population could increase under ideal conditions (like unlimited food and space)

carrying capacity (K)

The limit of number of individuals of a population that a environment can support (due to limited resources such as food, water, etc)

Overshoot

when a population becomes larger than the environment's carrying capacity

density dependent factors

factors whose effects on the population vary with the number of individuals in a given area EX: disease

density independent factors

limiting factor that affects all populations in similar ways, regardless of population size EX: natural disasters

survivorship curve type 1

low death rates during early and middle life and an increase in death rates among older age groups

survivorship curve type II

the death rate is constant over the organism's life span

survivorship curve type III

high death rates for the young, then a slower death rate for survivors

Population density

Number of individuals per unit area

crude birth rate (CBR)

the number of live births yearly per 1000 people in a population

crude death rate (CDR)

The number of deaths per year per 1,000 people in a population

Immigration

Movement of individuals into a population

Emmigration

movement of individuals out of a population

Developed country

a modern, industrialized country in which people are generally better educated and healthier and live longer than people in developing countries do

Developing country

A country that has low industrial production and little modern technology. Typically has low GDP & low standard of living

Infant Mortality Rate (IMR)

The total number of deaths in a year among infants under one year old for every 1,000 live births. This is higher in developing countries with less access to healthcare and clean water

Replacement level fertility

the number of children a couple must have to replace themselves (Roughly 2.1 in developed contries, but higher in developing countries)

Total fertility rate (TFR)

The average number of children a woman will have throughout her childbearing years.

population momentum

continued population growth after growth reduction measures have been implemented (the lag time between enacting birth control policies and the effects of those policies on population growth)

age structure diagram (population pyramid)

a graph that breaks down the divisions of age into cohorts and according to sex

cohort

A group of individuals of the same age.

per capita

per person

demographic transition

Movement of a population from a high birth rate, high death rate to a low birth rate, low death rate. This occurs as a country m oves from a subsitence economy to industrialization and increased affluence

family planning

the practice of regulating the number or spacing of offspring through the use of birth control

die-off/dieback

rapid population decline usually experienced after the overshoot of the carrying capacity

doubling time

The time required for a population to double in size. Calculated by 70/growth rate(r)

mortality

death rate

sex ratio

The ratio of males to females in a population. If skewed, it can slow population growth.

Rule of 70

Doubling time = 70/(percentage growth rate).

Population distribution

a description of how individuals are distributed with respect to one another (clumped, random, or uniform)