Chapter 7: Populations

Biotic potential

________: Maximum reproductive rate of a population if conditions were ideal.

Generalist

________: A species that can eat almost anything and live almost anywhere, like a cockroach.

Specialist

________: A species that only eats a specific item or live in only one place /habitat, like a koala.

III survivorship curve

Type ________: Almost all die young and only few live to adults.

Density

________- dependent factors: Things that become worse as the ________ of the population is larger.

capacity

Carrying ________: The number of organisms an ecosystem can support over time.

survivorship curve

Type II ________: Die at all stages of lifetime.

Population overshoot

________: When a population exceeds its carrying capacity and there is a dieback.

Demographic transition

________: The demographic transition model is another way to look at populations.

Age structure diagrams

________: Pyramid- shaped graphs showing the number of female and males in each age group.

Human populations

________ change in reaction to a variety of factors, including social and cultural factors.

Populations

________ in ecosystems change over time in response to factors in their environment and ________ are limited by availability of resources and space.

Generalist

A species that can eat almost anything and live almost anywhere, like a cockroach

Specialist

A species that only eats a specific item or live in only one place/habitat, like a koala

Biotic potential

Maximum reproductive rate of a population if conditions were ideal. In other words, if there was plenty of room, plenty of food, no predators, and so on, then how many of a particular species could live in the area.

Type I survivorship curve

Long life, not many die young. Example: humans.

Example

humans

Type II survivorship curve

Die at all stages of lifetime. Example: birds.

Example

birds

Type III survivorship curve

Almost all die young and only few live to adults. Example: fish.

Example

fish

Carrying capacity

The number of organisms an ecosystem can support over time. This is often shown in a graph.

Population overshoot

When a population exceeds its carrying capacity and there is a dieback

Age-structure diagrams

Pyramid-shaped graphs showing the number of female and males in each age group

Total fertility rate

The total number of children born, or likely to be born, to a woman in her lifetime if she were subject to the prevailing rate of age-specific fertility in the population

Infant mortality rate

The number of infants that die before their first birthday out of 1,000 births

Density-dependent factors

Things that become worse as the density of the population is larger. Infectious disease is an example of this since the more humans there are, the faster the disease can spread.

Density-independent factors

Things such as severe storms, droughts, heat waves, and fires that can influence populations regardless of their density. For example, a tornado doesn’t hit a city more than a rural area; where people live doesn’t matter to a tornado.

Rule of 70

This is a calculation to solve for how many years it will take for a population to double. 70/growth rate = doubling time. If you are given the doubling time, then rearrange the formula to solve for the growth rate.

Demographic transition

The demographic transition model is another way to look at populations.

Similar to age-structure diagrams, these are broken up into four stages

pre-industrial, transitional, industrial, and postindustrial

K Selected Species

• Large size

• Few offspring per year

• Live in stable environments in certain places

• Specialized diets

• Spend a lot of time and energy caring for their offspring

• Long life spans

• Reproduce more than once in their lifetime

• Can be impacted by invasive species or environmental changes

R Selected Species

• Small

• Many offspring

• Don’t take care of their offspring (or very little care)

• Mature early

• Short life spans

• Live almost anywhere

• Eat almost anything

• Not as impacted by invasive species or environmental changes