APES Unit 3

Generalist Species

Species that live in a variety of environments, eat a variety of food, have broad ecological tolerance, quickly reproduce, and have a wide niche.

Specialist Species

Species that require a specific habitat, have a limited diet, narrow ecological tolerance, have a narrow niche, and are advantaged in constant habitats.

K-selected Species

Species that tend to be large, have few offspring, expend significant energy for each offspring, mature after many years of parental care, and live in stable environments.

r-selected Species

Species that tend to be small, have many offspring, expend minimal energy for each offspring, mature early, and are able to thrive in disturbed environments.

Carrying Capacity

The maximum number of organisms an environment can support without degradation of resources, influenced by biotic potential and resource availability.

Survivorship Curves

Graphs showing time vs. percent of organisms surviving, categorized into Type I (Late Loss), Type II (Constant Loss), and Type III (Early Loss).

Total Fertility Rate

The average number of children a woman will have during her childbearing years, influenced by factors like age of first pregnancy, educational opportunities, and governmental policies.

Age Structure Diagrams

Population pyramids showing the distribution of ages in a population, with shapes indicating population growth trends and reproductive abilities.

Human Population Dynamics

Factors affecting population growth or decline, including birth rates, death rates, education in women, infant mortality, age of marriage, and nutrition.

Demographic Transition

A model showing trends in birth rate, death rate, and total population as nations progress through stages of industrialization, leading to changes in population growth rates.

Type 1: Late Loss

A large % of the population survive from birth to death; They survive because they care for the young, thus increasing chances of survival to old age.

Type 2: Constant Loss

Death rate constant from birth to death

Type 3: Early Loss

A large % of the population dies early life, a small amount make it to adulthood; There is no parental care, so there is a high infant mortality rate 

Biotic Potential

the maximum reproductive rate under ideal conditions

Overshoot

when a population exceeds carrying capacity 

Dieback

bringing an art overshot population back to its carrying capacity due to depletion of resources from overpopulation 

Density Dependent Resistance Factors

Tend to be biotic; Have a strong influence when the number of organisms per unit area reaches a certain level; Competition for resources; Predation; Parasitism/Disease

Density Independent Resistance Factors

Tend to be abiotic; Have an affect on all populations, regardless of size of density; Natural disasters, severe weather events; Drought

Exponential Growth

unlimited resources; When a species first begins to evolve in an ecosystem, the growth will be exponential until any species hits its carrying capacity

Logistic Growth

limited resources, competition is present 

Fecundity

the ability to produce offspring 

Age structure diagram

population pyramid; Show the distribution of ages in a certain population; Divided by male and female; Not always pyramidal; Come in many shapes 

Bottom heavy - population is growing quickly

Younger age groups are are the largest percent of the population; They are reproducing longer; Usually an indicator of a developing population

Middle Heavy - population growth is stable

Rectangular shape; All reproductive groups seem to have similar percentages; Not as many younger groups for reproduction; Nations in this shape are developed and well off

Top Heavy - population may be negative/declining

Inverted pyramid shape; Largest percentage of the population is closer to post-reproductive; Economically and socially developed, higher education common; Many women delay having children; Long term social services may be impacted 

The Rule of 70

•  used for calculating doubling time

  • Doubling Time - the amount of time for a population to double at a constant growth rate

  • 70/r = Doubling time

  • r = growth rate of a population

    • For these calculations r needs to be a number percentage for example 1.55%, not 0.0155