Population Growth Models

Question 1

Population density

Answer 1

the average number of organisms in a population per unit of area or volume

Question 2

Random distribution

Answer 2

a pattern of spacing between members of a species where each individual’s position is independent of the others

Question 3

Uniform distribution

Answer 3

a spatial arrangement of organisms where individuals are spaced out in a fairly regular pattern

Question 4

Clumped distribution

Answer 4

a spatial pattern where individuals of a population are grouped together in small areas, rather than being spread out evenly or at unpredictable distances

Question 5

Age structure

Answer 5

the proportions of individuals at different life stages within a population

Question 6

Birthrate

Answer 6

the number of live births in a population over a given period of time, usually a year

Question 7

Death rate

Answer 7

he number of deaths in a population over a period of time, usually expressed per 1000 or 100,000 people

Question 8

Immigration rate

Answer 8

The number of individuals of a similar species that have invaded the habitat who have come from elsewhere during specific period

Question 9

Emigration rate

Answer 9

The number of individuals of a similar species that have left the habitat and have migrated elsewhere in specific period

Question 10

Sigmoid growth curve

Answer 10

A growth pattern in which an organism’s population density rises slowly originally in a fresh setting, in a favorable acceleration stage ; then rises quickly approaching an exponential growth rate as in the J-shaped curve ; but then decreases in a negative acceleration stage

Question 11

Lag phase

Answer 11

the initial stage of growth when the population remains constant while adjusting to the environmental conditions

Question 12

Exponential phase

Answer 12

a period when growth is at a constant, maximum rate, ususally doubling in shorter periods of time

Question 13

Stationary phase

Answer 13

a stage of growth where the increase in populations stops as birth and death rates become equal

Question 14

Death phase

Answer 14

the final stage of growth, when the population decreases exponentially due to limiting factors

Question 15

Carrying capacity

Answer 15

the maximum number of organisms that an ecosystem can support without degrading the habitat

Question 16

Limiting factor

Answer 16

a condition or variable that can slow or stop a population from growing, or limit the rate of a reaction

Question 17

Life-history plan

Answer 17

the pattern of an organism’s survival and reproduction, and the traits that affect it. Life history theory is the study of how organisms use their energy to grow, maintain their bodies, defend themselves, reproduce, raise their young, and avoid death.

Question 18

Density dependent limiting factors

Answer 18

factors that affect a population’s growth rate based on the population’s density

Question 19

Density independent limiting factors

Answer 19

factors that impact population sizes regardless of the population’s size. These factors are often associated with non-living things, or abiotic factors, and can include: weather, climate, natural disasters, and human activity