Biology 5.3

Question 1

Population

Answer 1

group of living organisms of the same species in a given area

Question 2

Community

Answer 2

Group of populations of various species in a given area

Question 3

Ecosystem

Answer 3

Relationship between biotic community and abiotic environment

Question 4

Biosphere

Answer 4

All regions of earth that contain living things

Question 5

Habitat

Answer 5

Environment where a given organism lives, temperature range, soil type, etc

Question 6

Niche

Answer 6

Role of organism within its ecosystem, includes habitat, food sources, method of obtaining food, reproductive cycles, etc

Question 7

Population ecology

Answer 7

Growth, abundance, and distribution of populations.

• Size: total number of individuals living in a population
• Density: number of organisms per area or volume occupied
• Dispersion: How individuals are distributed in a population; clumped, uniform or random
• Age structure: Number of individuals at each age within a population, shape of the age structure indicates population’s growth rate (ex. pyramid shape, rectangular shape, etc.)

Question 8

Survivorship Curves

Answer 8

Represents mortality of individuals of a species over their lifetime, relative survival rates by age. Type I, II and III

Question 9

Type I Survivorship Curve

Answer 9

Species which most organisms survive to their median age, then majority die after. (ex. humans)

Question 10

Type II Survivorship Curve

Answer 10

Species with random rate of survival, likelihood of mortality is the same at every age

Question 11

Type III Survivorship Curve

Answer 11

Species which most individuals die young, common in species with larvae where most are eaten

Question 12

Factors affecting population growth

Answer 12

Biotic potential, carrying capacity, limiting factors

Question 13

Biotic potential

Answer 13

A factor affecting population growth. Maximum growth rate of a species under perfect ideal conditions with unlimited resources and no restricting factors. Depends on a species’ age at reproductive maturity, amount of offspring made each reproductive event, frequency of reproduction, and survivorship of offspring

Question 14

Carrying capacity

Answer 14

A factor affecting population growth. Maximum number of organisms in a population that can be sustained by their habitat

Question 15

Limiting factors

Answer 15

A factor affecting population growth. Factors preventing species from reaching their full potential.

• Density dependent factors means the bigger the organism’s population size, the greater the effect of the limiting factor
• Density independent factors do not depend on population size

Question 16

Population growth equation

Answer 16

R = (births-deaths)/N
R is the reproductive/growth rate which is relative change in number of individuals. N is the population size at the beginning of the interval. (births-deaths) is the net increase of individuals.

Question 17

Intrinsic rate of growth

Answer 17

When R, the reproductive/growth rate, is maximum or equal to its biotic potential

Question 18

Exponential growth

Answer 18

Occurs when reproductive rate R, determined by population growth equation, is greater than 0

Question 19

Logistic growth

Answer 19

Occurs when there is a limiting factor preventing exponential growth, causing population size to be restricted to a carrying capacity of the habitat. If N = K and K = carrying capacity, population reached carrying capacity, reproductive rate is 0 and size of population stabilizes. As population size increases, reproductive rate decreases.

Question 20

K-selected species

Answer 20

Stable populations with low number of offspring that tend to be large

Question 21

R-selected species

Answer 21

High growth rates, in less-crowded niches, produce many offspring with low probability of surviving to adulthood.