Population Ecology 1 - Growth Models

Question 1

Population

Answer 1

group of interacting organisms of the same species + includes individuals of all ages of stages (pre-reproductive juveniles and reproductive adults)

Question 2

Demographic Structure

Answer 2

quantifying the numbers of individuals of each age or stage in a population

Question 3

Population Size

Answer 3

varied total number of individuals in a population

Question 4

Population Density

Answer 4

concentration of individuals within a species in a specific geographic locale

Question 5

Geographic Range

Answer 5

spatial area where a species is found
- determined by limits (physical limits) that the species can tolerate and by the encroachment of other species

Question 6

Exponential Population Growth

Answer 6

• assumed that each individual produces two offspring in its lifetimes then dies (double the population size each generation)
• ideal population with unlimited resources
• births and deaths do not change over time = constant growth rate
• population size explodes in size very quickly

Question 7

Exponential Growth Equation

Answer 7

r = growth rate (intrinsic rate of natural increase AKA birth rate - death rate)
N = population size

dN/dt = rN

Question 8

Logistic Population Growth Model

Answer 8

• resource limitation affects population growth (CARRYING CAPACITY)
• population growth rate slows as the population size increases, and growth stops when the population reaches carrying capacity

Question 9

Carrying Capacity

Answer 9

the maximum population size that the environment can sustain

Question 10

Logistic Population Growth Equation

Answer 10

• incorportaion of a density-dependent term (K-N/K)
• K = carrying capacity

dN/dt = rN(K-N/K)

Question 11

Factors on Population Size

Answer 11

1. Biological (predation, competition, parasitism, mutualism, disease)
2. Non-Biological (temperature, precipitation, disturbance, pollution, salinity, pH)

All of these can CHANGE a population size, but only BIOLOGICAL factors (except mutualism) can “regulate” a population, meaning they can push a population to carrying capacity

Question 12

Factors on Population Size: Mutualism

Answer 12

Mutualism does not regulate population size because it promotes population increase through beneficial interactions with other species

Question 13

Population regulated by Density

Answer 13

• Territoriality
• Disease
• Predation
• Toxic Waste

Density-dependent population regulation: higher densities yield lower survival

Question 14

Territoriality

Answer 14

maintaining a territory will enable an individual to capture enough food to reproduce, where space is a limiting resource

Question 15

Disease

Answer 15

transmission rate often depends on population density

Question 16

Predation

Answer 16

Predators may concentrate on the most abundant prey

Question 17

Toxic Wastes

Answer 17

Metabolic by-products accumulate as populations grow