APES Unit Three

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.

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.

K-selected species

Species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age.

r-selected species

Species that reproduce early in their life span and produce large numbers of usually small and short-lived offspring in a short period.

biotic potential

The maximum rate at which a population could increase under ideal conditions (follows exponential growth)

Carrying Capacity

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

Type 1 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 they approach old age

type 2 survivorship curve

a pattern of survival over time in which there is a relatively constant decline in survivorship throughout most of the life span

type 3 survivorship curve

a pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood

population overshoot

Occurs when the population of a species exceeds the carrying capacity. As a result, resources run out faster and the population plummets

Density Dependent Limiting Factors

limiting factors that are affected by the number of individuals in a given area (food, space, disease, etc).

Density Independent limiting factors

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

Age structure diagrams

graph of the numbers of males and females within different age groups of a population

Declining growth age structure diagram

More people in the older ages and less in the younger ages (reproductive ages)

Rapid growth age structure diagram

The bottom of the pyramid, bottom (younger ages) has the largest population, and it' decreases going up the pyramid.

stable growth age structure diagram

Mostly equal levels of people throughout the ages (obvi lower levels of old people because they die of natural causes)

Fertility Rate

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

Replacement level fertility

The number of children that a woman/couple must have in order to replace the number of people in the population who die. This should create stable growth. (between 2.1 and 2.5)

infant mortality rate

The percentage of children who die before their first birthday within a particular area or country.

Malthusian Theory

Starvation is the inevitable result of population growth, because the population increases at a geometric rate while food supply can only increase linearly

Immigration

Movement of individuals into a population

Emigration

movement of individuals out of an area

Rule of 70/ Doubling time

Doubling time (in years) = 70/(percentage growth rate).

Population growth rate

explains how fast a given population grows

(birth rate + immigration)- (death rate + emigration) * note you need to convert crude rates to regular rates if it is out of 1,000*

Population momentum

continued population growth after growth reduction measures have been implemented (takes a few generations for it to truly reduce the population)

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.

The demographic transition model

A sequence of demographic changes in which a country moves from high birth and death rates to low birth and death rates through time.

Demographic transition model stage 1

No growth; high birth and death rates; associated with preindustrial societies

Demographic transition model stage 2

High birth rate and rapidly falling death rates

Very high population increase

Associated with societies changing from preindustrial to industrial

Demographic transition model stage 3

Slow to no growth; fertility rates begin to fall, industrial society

Demographic transition model stage 4

no growth or declining growth in some cases; birth rates continue to fall, accompanied by steady low death rates, associated with postindustrial societies

developed countries

countries with strong economies (high GDP) and a high quality of life (typically in stage 3 or 4 of DTM)

developing countries

countries with less productive economies (Low GDP) and a lower quality of life (typically in stage 1 or 2 of DTM)

Gross Domestic Product (GDP)

A measurement of the total goods and services produced within a country.

Population Density

A measurement of the number of people per given unit of land

Population Dieback

a rapid decrease in numbers experienced by a population of organisms that has temporarily exceeded, or overshot, its carrying capacity

Percent Change Formula

((new-old)/old) x 100