Key Concepts

Question 1

Abiotic Factor

Answer 1

A non living, physical factor that may influence an organism or ecosystem, for example temperature, sunlight, salinity, precipitation

Question 2

Biochemical Oxygen demand (BOD)

Answer 2

A measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity

Question 3

Biodegradable

Answer 3

Capable of being broken down by natural biological processes for example, the activities of decomposer organisms

Question 4

Biodiversity

Answer 4

The amount of biological or living diversity per unit area. It includes the concepts of species diversity, habitat diversity and genetic diversity

Question 5

Biomass

Answer 5

The mass of organic material in organisms or ecosystems, usually per unit area. Sometimes the term “dry weight biomass”is used where mass is measured after the removal of water. Water is not organic material and inorganic material is usually relatively insignificant in terms of mass.

Question 6

Biome

Answer 6

A collection of ecosystems sharing similar climatic conditions, example tundra, tropical rainforest, desert.

Question 7

Biosphere

Answer 7

The part of the earth inhabited by organisms, that is, the narrow zone (a few kilometers in thickness) in which plants and animals exist. It extends from the upper part of the atmosphere (where birds, insects and wind blown pollen may be found) down to the deepest part of the Earths crust to which living organisms venture.

Question 8

Biotic factor

Answer 8

A living, biological factor that may influence an organism or ecosystem for example predation, parasitism, disease, competition

Question 9

Carrying Capacity

Answer 9

The maximum number of a species or load that can be sustainably supported by a given environment

Question 10

Climax community

Answer 10

A community of organisms that is more or less stable, and that is in equilibrium with natural environmental conditions such as climate, the end point of ecological succession

Question 11

Community

Answer 11

A group of populations living and interacting with each other in a common habitat

Question 12

Competition

Answer 12

A common demand by two or more organisms upon a limited supply of a resource for example, food, water, light, space, mates, nesting sites. It may be intraspecific or interspecific.

Question 13

Correlation

Answer 13

A measure of the association between two variables. If two variables tend to move up or down together, they are said to be negatively correlated. if they tend to move in opposite directions, they are said to be negatively correlated.

Question 14

Crude birth rate

Answer 14

The number of births per thousand individuals in a population per year

Question 15

Crude death rate

Answer 15

The number of deaths per thousand individuals in a population per year.

Question 16

Demographic transition

Answer 16

A general model describing the changing levels of fertility and morality in a human population overtime. It was developed with reference to the transitions experienced as developed countries (for example those of North America, Europe) passed through the o process es of industrialization and urbanization

Question 17

Diversity

Answer 17

A generic term for heterogeneity. The scientific meaning of diversity becomes clear from the context in which it is used , it may refer to heterogeneity of species or habitat, or to genetic heterogeneity

Question 18

Diversity Genetic

Answer 18

The range of genetic material present in a gene pool or population of a species

Question 19

Diversity Habitat

Answer 19

The range of different habitats or number of ecological niches per unit area in an ecosystem, community or biome. Conservation of habitat diversity usually leads to the conservation of species and genetic diversity