2.2 Population Growth

Question 1

What does the variable N stand for?

Answer 1

population size

Question 2

What does the variable t stand for?

Answer 2

time

Question 3

What does the dN/dt stand for?

Answer 3

population growth rate

Question 4

What does r stand for?

Answer 4

maximum per capita growth rate

Question 5

What does the variable N-sub-zero stand for?

Answer 5

initial population size

Question 6

What does the variable K stand for?

Answer 6

carrying capacity

Question 7

What is carrying capacity?

Answer 7

the maximum population size that an environment can support without degrading it

Question 8

What are the four main factors that affect population growth?

Answer 8

birth, death, immigration, and emigration

Question 9

What is an equation for positive growth? Use the first letter of each of the four main factors as the variable in your equation.

Answer 9

B + I > D + E

Question 10

Describe an exponential growth model with an x-axis of time and a y-axis of population size.

Answer 10

An exponential growth model features a seemingly infinite line that keeps increasing. In the beginning, there is a lag phase where the growth starts slowly, but then it rapidly increases, creating a steeper slope.

Question 11

What is an example of a population that would resemble the exponential growth model?

Answer 11

A new population with an idyllic environment or a parasitic population.

Question 12

Describe a logistic growth model with an x-axis of time and a y-axis of population size.

Answer 12

The graph might start off looking like an example of an exponential growth model, but then it plateaus. This is when the population reaches its carrying capacity, and the population will hover below and above this level.

Question 13

Describe a logistic growth model with an x-axis of population size and a y-axis of population growth rate.

Answer 13

The graph will look like a curve. Starting at 0, the curve will rise to its highest point and then fall back down to be level with the starting point.

Question 14

How does the exponential and logistic growth model change when r is changed?

Answer 14

When r is increased, the growth rate will increase for both graphs. This is because r is the maximum per-capita growth rate. So if each individual can reproduce more, then the population will naturally increase at a faster rate.

Question 15

How does the exponential and logistic growth model change when N (in this case use the starting population size) is changed?

Answer 15

When N is increased, the exponential and logistic growth model will also grow at a faster rate. If the population starts with more individuals it can reproduce faster.

Question 16

How does the exponential and logistic growth model change when K is changed?

Answer 16

When the carrying capacity is increased, the population can reach a higher point before plateauing. This means that the environment can support more of the population without degrading the habitat.

Question 17

What are the two main limiting factors of population size?

Answer 17

density-dependent factors and density-independent factors

Question 18

What are some examples of density-independent factors?

Answer 18

Density-independent factors are mainly abiotic factors. They are not influenced by the density, so usually they come from the weather. For example, droughts, floods, and other natural disasters are all forms of density-independent limiting factors.

Question 19

What is the difference between intraspecific competition and interspecific predation?

Answer 19

Intraspecific competition is competition inside the species. Meanwhile, interspecific predation stems from outside factors such as predators and preys.

Question 20

What are the four main limiting factors under the category of density-dependent factors?

Answer 20

intraspecific competition, interspecific predation, disease/parasites, and social behavior