Populations and Communities

Question 1

What is exponential growth in populations?

Answer 1

When the rate of population growth remains constant, causing the population to increase rapidly over time

Question 2

Define:
Carrying capacity (K)

Answer 2

The maximum number of individuals that an ecosystem can support without degrading its resources

Question 3

List the four factors that affect population growth

Answer 3

1. Birth Rate (natality rate)
2. Death Rate (mortality rate)
3. Immigration
4. Emigration

Question 4

Explain the difference between density-dependent and density-independent limiting factors

Answer 4

Density-dependent factors are influenced by population density (e.g., competition, predation), while density-independent factors affect populations regardless of density (e.g., natural disasters, climate)

Question 5

Define:
r-selection and provide two examples

Answer 5

A reproductive strategy focused on producing many offspring with low parental care; e.g., insects, weeds

Question 6

Define:
K-selection and provide two examples

Answer 6

A reproductive strategy focused on producing fewer offspring with higher parental care; e.g., elephants, humans

Question 7

What is the competitive exclusion principle?

Answer 7

The idea that no two species can occupy the exact same niche in the same ecosystem

Question 8

Fill in the blank:
Invasive species can _____ native species for resources, disrupt food chains, and alter habitats

Answer 8

Invasive species can OUTCOMPETE native species for resources, disrupt food chains, and alter habitats

Question 9

Explain the difference between species richness and species evenness

Answer 9

Species richness is the number of different species in an ecosystem, while species evenness is the relative abundance of each species in an ecosystem

Question 10

What is the difference between emigration and immigration?

Answer 10

Emigration is the movement of individuals out of a population, while immigration is the movement of individuals into a population

Question 11

Describe the J-curve and S-curve in population growth

Answer 11

J-curve: represents exponential growth, with a rapid increase in population size
S-curve: represents logistic growth, with population growth leveling off as it reaches carrying capacity

Question 12

What are the three main types of survivorship curves?

Answer 12

Type I: high survival rate throughout life, with most mortality occurring in older age (e.g., humans)
Type II: constant mortality rate throughout life (e.g., birds)
Type III: high mortality rate early in life, with survivors living long lives (e.g., fish)

Question 13

What is a demographic bottleneck?

Answer 13

A period of sharp reduction in population size due to environmental events or human activities, followed by a recovery and genetic drift

Question 14

Define: carrying capacity (K) and its significance in population ecology

Answer 14

The maximum population size that a given environment can sustain indefinitely; it helps predict population growth and decline, as well as the impact of environmental changes on a population

Question 15

What are density-independent factors? Give two examples

Answer 15

Factors that affect population growth regardless of population density

Examples: natural disasters and extreme weather conditions

Question 16

What is the difference between r-selected and K-selected species?

Answer 16

r-selected species: reproduce rapidly, have many offspring, and exhibit rapid population growth (e.g., insects)
K-selected species: reproduce slowly, have few offspring, and exhibit slower population growth (e.g., mammals)

Question 17

What is the relationship between population growth and carrying capacity?

Answer 17

Population growth is influenced by the carrying capacity of an environment, with populations growing when resources are abundant and declining when they reach the carrying capacity or environmental limits