AP Environmental Science- Unit 3

APES unit 3 main terms

Generalist Species

A species that can thrive in a wide variety of environmental conditions and utilize a broad range of resources.

Characteristics of generalist species?

Broad Niche, Adaptable, Survival in diverse environments, many different food sources.

Specialist Species

A species that can thrive only in a narrow range of environmental conditions or has a very limited diet or resource requirement.

Characteristics of Specialist species?

Narrow niche, less adaptable to change, thrives in specific environments, few resources.

R-selected species

Species that prioritize rapid reproduction and producing many offspring, often in unstable or unpredictable environments.

Characteristics of R-selective species?

High reproductive rates, small size, early maturity, low parental investment.

K-selected species

Species that prioritize survival and producing fewer, well-cared-for offspring, typically in stable, resource-limited environments.

Characteristics of K-selective species?

Lower reproductive rates, larger size, late maturity, high parental investment.

Invasive species

Non-native species that disrupt ecosystems, outcompete native species, and cause environmental or economic harm. (R selective species can be invaders).

Survivorship curve

A graph that shows the proportion of individuals in a cohort. K-selective, R-selective.

Type I survivorship curve

high survival rates in early and middle life, with a significant drop in survivorship in older age. (humans or large mammals).

Type II survivorship curve

constant probability of death throughout the organism's life, leading to a linear decline in survival rates. (Certain birds and reptiles).

Type III Survivorship Curve

characterized by low survival rates in early life, with a few individuals surviving to adulthood. (Many fish and amphibians).

Carrying Capacity (K)

Maximum population size that a particular environment can sustainably support over a long period, given the available resources. (Food, water, shelter, space).

Age Structure Diagram (Population Pyramid)

A graph of the distribution of a population by age groups and sex at a specific point in time. It provides insights into the potential for future population growth or decline.

Wide base of pyramid

indicates a high proportion of younger individuals, suggesting potential for population growth.

Narrow base of pyramid

Slowly growing or even declining population due to low birth rates.

Wide top of pyramid

indicates a high proportion of older individuals, suggesting an aging population and potential future decline.

Total Fertility Rate (TFR)

Average # of children a woman is expected to have in her lifetime. (ages 15-49)

High TFR

Rapid population growth, less developed countries, low resources. It often indicates greater child dependency ratios and higher pressure on resources due to large family sizes.

Low TFR

Slower population growth, often found in more developed countries, indicating better access to education and family planning.

Doubling Time (Rule of 70)

A method to estimate the time it takes for a population to double in size by dividing 70 by the annual growth rate percentage. (70/growth rate).

Demographic Transition Model (DTM)

Historical shift in birth & death rates in human populations over time due to industrialized economic systems.

Stage 1

high birth and death rates=leading to a stable population.

Stage 2

declining death rates with high birth rates, resulting in rapid population growth.

Stage 3

declining birth rates as a society becomes more urbanized, leading to a slowing population growth.

Stage 4

low birth and death rates, stabilizing the population size.