Population Size And Ecosystems

Question 1

What does birth rate mean?

Answer 1

The reproductive capacity of a population

Question 2

What does death rate mean?

Answer 2

The proportion of individuals dying per unit time

Question 3

What is immigration?

Answer 3

The movement of individuals into a population of the same species

Question 4

What is emigration?

Answer 4

The movement of individuals out of a population of the same species

Question 5

What is the lag phase?

Answer 5

Where there is a slow rate of reproduction because individuals are reaching sexual maturity

Question 6

What is the log/exponential phase?

Answer 6

Where there is a rapid increase in population numbers as more individuals are available for reproduction.

Question 7

What is the stationary phase?

Answer 7

Where the birth and death rates are roughly equal, so the population remains roughly the same

Question 8

What is the death phase?

Answer 8

When the death rate is greater than the birth rate due to environmental factors.

Question 9

What are some density dependent factors that affect population size?

Answer 9

—Disease and parasitism
—Food availability
—Toxic waste build up

Question 10

What are some density independent factors affecting population size?

Answer 10

—Floods
—Fires
—Sudden temperature changes

Question 11

What is intra-specific competition?

Answer 11

Competition between members of the same species

Question 12

What is inter-specific competition?

Answer 12

Competition between members of different species

Question 13

Why does the predator population go up when the prey population goes up?

Answer 13

When the prey population increases, there is more food for the predators so their population increases

Question 14

Why can only one species occupy a particular niche in an ecosystem?

Answer 14

One species will always outcompete the other

Question 15

What is the study of species abundance called?

Answer 15

Biogeography

Question 16

What are two ways of counting individuals in an area?

Answer 16

Density, where you count the amount in a number of quadrats and calculate a mean, and percentage cover, where you count the percentage of quadrats with at least one individual in it

Question 17

How do you sample the change in species over time?

Answer 17

Set up a permanent area in the habitat, and create a 10x10 grid. Generate random coordinates and calculate the percentage cover of species. Return periodically to compare

Question 18

How would you sample when there is a change in an abiotic factor?

Answer 18

A line along the gradient is measured along, called a transect

Question 19

What is an ecosystem?

Answer 19

A characteristic community of interdependent species interacting with abiotic components in their habitat.

Question 20

What is a habitat?

Answer 20

The place where an organism lives

Question 21

What is a community?

Answer 21

Populations of different species living in the same habitat

Question 22

What are trophic levels?

Answer 22

Feeding levels within an ecosystem

Question 23

What is the equation for photosynthetic efficiency?

Answer 23

Photosynthetic efficiency=energy incorporated into photosynthetic products/total light energy falling on the plant X100

Question 24

Why isn’t all light energy that falls on a plant absorbed by photosynthetic pigments?

Answer 24

-Reflection
-Respiration requirements of photosynthesis
-Need for optimal solar radiation levels

Question 25

What is gross primary productivity?

Answer 25

The rate of production of chemical energy in organic chemicals by photosynthesis

Question 26

What is net primary productivity?

Answer 26

GPP minus the energy used up by the producers in respiration in a year

Question 27

How much is the average GPP of global sunlight?

Answer 27

0.2%

Question 28

What does NPP represent?

Answer 28

The potential food/chemical energy available to heterotrophs in ecosystems

Question 29

What is biological productivity?

Answer 29

The rate at which biomass accumulates in an ecosystem