lOMoARcPSD| 54339004
IB ESS VOCABULARY WORDS QUESTIONS
AND ANSWERS WITH VERIFIED SOLUTIONS
100% CORRECT RATED A+
IB ESS Key Terms – Ecology & Systems
Abiotic Factor
✔✔ A non-living physical or chemical component of an ecosystem that may influence
organisms; e.g. temperature, sunlight, pH, salinity, and precipitation.
Biochemical Oxygen Demand (BOD)
✔✔ A measure of the amount of dissolved oxygen needed by aerobic organisms to break down
organic material in a given volume of water.
Biodegradable
✔✔ Capable of being decomposed by natural biological processes, typically through the action
of microorganisms.
Biodiversity
✔✔ The variety of life per unit area, encompassing species diversity, genetic diversity, and
habitat diversity.
Biomass
✔✔ The total mass of organic matter in organisms or ecosystems per unit area, often measured
as "dry weight biomass" (excluding water content).
Biome
✔✔ A group of ecosystems with similar climates and typical organisms; e.g. tundra, tropical
rainforest, or desert.
Biosphere
✔✔ The thin layer of Earth where life exists—from the upper atmosphere to the deepest parts
of the crust inhabited by organisms.
Biotic Factor
✔✔ A living component that affects an organism or ecosystem; e.g. predation, parasitism,
disease, and competition.
Carrying Capacity
✔✔ The maximum population size of a species that an environment can sustainably support
over time.
Climax Community
✔✔ A stable, mature community in equilibrium with its environment, representing the final
stage of ecological succession.
Community - ANSWER✔✔A group of populations living and interacting with each other in a
common habitat.
Competition - ANSWER✔✔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.
, lOMoARcPSD| 54339004
Correlation - ANSWER✔✔A measure of the association between two variables. If two
variables tend to move up or down together, they are said to be positively correlated. If they
tend to move in opposite directions, they are said to be negatively correlated.
Crude Birth Rate - ANSWER✔✔The number of births per thousand individuals in a population
per year.
Crude Death Rate - ANSWER✔✔The number of deaths per thousand individuals in a
population per year.
Demographic Transition - ANSWER✔✔A general model describing the changing levels of
fertility and mortality in a human population over time. It was developed with reference to the
transition experienced as developed countries (for example, those of North America, Europe,
Australasia) passed through the processes of industrialization and urbanization.
Diversity - ANSWER✔✔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.
Diversity, Genetic - ANSWER✔✔The range of genetic material present in a gene pool or
population of a species.
Diversity, Habitat - ANSWER✔✔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.
Diversity Index - ANSWER✔✔A numerical measure of species diversity that is derived from
both the number of species present and their relative abundance.
Diversity, Species - ANSWER✔✔The variety of species per unit area. This includes both the
number of species present and their relative abundance.
Doubling Time - ANSWER✔✔The number of years it would take a population to double its
size at its current growth rate. A natural increase rate of 1% will enable a human population to
double in 70 years. Other doubling times can then be calculated proportionately, that is, the
doubling time for any human population is equal to 70 divided by the natural increase rate.
Ecological Footprint - ANSWER✔✔The area of land and water required to support a defined
human population at a given standard of living. The measure takes account of the area required
to provide all the resources needed by the population, and the assimilation of all wastes. (A
method of calculation is provided in 3.8.2).
IB ESS VOCABULARY WORDS QUESTIONS
AND ANSWERS WITH VERIFIED SOLUTIONS
100% CORRECT RATED A+
IB ESS Key Terms – Ecology & Systems
Abiotic Factor
✔✔ A non-living physical or chemical component of an ecosystem that may influence
organisms; e.g. temperature, sunlight, pH, salinity, and precipitation.
Biochemical Oxygen Demand (BOD)
✔✔ A measure of the amount of dissolved oxygen needed by aerobic organisms to break down
organic material in a given volume of water.
Biodegradable
✔✔ Capable of being decomposed by natural biological processes, typically through the action
of microorganisms.
Biodiversity
✔✔ The variety of life per unit area, encompassing species diversity, genetic diversity, and
habitat diversity.
Biomass
✔✔ The total mass of organic matter in organisms or ecosystems per unit area, often measured
as "dry weight biomass" (excluding water content).
Biome
✔✔ A group of ecosystems with similar climates and typical organisms; e.g. tundra, tropical
rainforest, or desert.
Biosphere
✔✔ The thin layer of Earth where life exists—from the upper atmosphere to the deepest parts
of the crust inhabited by organisms.
Biotic Factor
✔✔ A living component that affects an organism or ecosystem; e.g. predation, parasitism,
disease, and competition.
Carrying Capacity
✔✔ The maximum population size of a species that an environment can sustainably support
over time.
Climax Community
✔✔ A stable, mature community in equilibrium with its environment, representing the final
stage of ecological succession.
Community - ANSWER✔✔A group of populations living and interacting with each other in a
common habitat.
Competition - ANSWER✔✔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.
, lOMoARcPSD| 54339004
Correlation - ANSWER✔✔A measure of the association between two variables. If two
variables tend to move up or down together, they are said to be positively correlated. If they
tend to move in opposite directions, they are said to be negatively correlated.
Crude Birth Rate - ANSWER✔✔The number of births per thousand individuals in a population
per year.
Crude Death Rate - ANSWER✔✔The number of deaths per thousand individuals in a
population per year.
Demographic Transition - ANSWER✔✔A general model describing the changing levels of
fertility and mortality in a human population over time. It was developed with reference to the
transition experienced as developed countries (for example, those of North America, Europe,
Australasia) passed through the processes of industrialization and urbanization.
Diversity - ANSWER✔✔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.
Diversity, Genetic - ANSWER✔✔The range of genetic material present in a gene pool or
population of a species.
Diversity, Habitat - ANSWER✔✔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.
Diversity Index - ANSWER✔✔A numerical measure of species diversity that is derived from
both the number of species present and their relative abundance.
Diversity, Species - ANSWER✔✔The variety of species per unit area. This includes both the
number of species present and their relative abundance.
Doubling Time - ANSWER✔✔The number of years it would take a population to double its
size at its current growth rate. A natural increase rate of 1% will enable a human population to
double in 70 years. Other doubling times can then be calculated proportionately, that is, the
doubling time for any human population is equal to 70 divided by the natural increase rate.
Ecological Footprint - ANSWER✔✔The area of land and water required to support a defined
human population at a given standard of living. The measure takes account of the area required
to provide all the resources needed by the population, and the assimilation of all wastes. (A
method of calculation is provided in 3.8.2).
