IB ESS Topic 2 Vocabulary

Abiotic Factor

Abiotic Factor

A non-living, physical factor that may influence an organism or ecosystem

Biotic factor

A living biological factor that may influence an organism or ecosystem

Biosphere

The part of the Earth inhibited by organisms

Biome

A collection of ecosystems that share similar climates

Biomass

The mass of organic material in organisms or ecosystems, usually per area

Niche

A set of biotic and abiotic conditions and resources that an organism or population depends on

Habitat

The environment in which a species usually lives

Population

A group of the same species, living in the same area at the same time, interacting and breeding.

Species

A group of organisms that are capable of breeding and producing fertile offspring. Share similar characteristics and genetic makeup.

Trophic Level

The place an organism occupies on a food chain

Interspecific Competition

The struggle between two organisms of different species for the same (biotic or abiotic) resource.

Intraspecific Competition

The struggle between two organisms of the same species for the same (biotic or abiotic) resource.

Predation

A relationship between two organisms in which one hunts, kills, and eats the other one.

Herbivory

A form of competition in which an organism eats producers such as plants, algae, and photosynthesising bacteria

Ecological Niche

The role of a species in an ecosystem

Ecosystem

Organisms’ interactions with biotic and abiotic factors. A community of living organisms in a particular area.

Community

Populations of different species interacting in a shared environment.

Individual

One living organism of a species

Parasite

Lives on or in living hosts and gets their food from the host, at the host’s detriment.

Parasitism

Where one species lives off another gaining most of its food.

Mutualism

Symbiotic relationship in which both species benefit

Symbiotic Relationship

A close, prolonged association between two or more different species

Herbivore

Plant eating organism

Carnivore

Animal eating organism

Omnivore

Organism which eats both animals and plants

Detritivore

Organism that feeds on decomposing organic matter. Eats dead plant/animal material.

Decomposer

Organism which breaks down dead materials to recycle nutrients.

Scavenger

Organism which eats mostly decaying biomass, usually carnivores

Saprotroph

Organisms that live on dead or decaying organisms

Carrying Capacity

The maximum number of species that can be sustainably supported by a given area

Limiting factors

Slow down the growth of a population as it reaches its carrying capacity

Density dependant limiting factors

Mostly biotic, cause a change in population with a higher density

Density independent limiting factor

Mostly abiotic, change the size of a population regardless of density