4.1 Species, Communities and ecosystems

Species

A group of organisms that can potentially interbreed to produce fertile, viable offspring

Population

A group of organisms of the same species, living in the same area at the same time

Community

A group of populations living together and interacting with each other within a given area

Habitat

The environment in which a species normally lives, or the location of a living organism

Ecosystem

A community and its abiotic environment

Ecology

The study of the relationship between living organisms, or between living organisms and their environment.

Autotrophs

* Synthesizes its own organic molecules from simple inorganic substances
* Energy for this process is derived from sunlight (photosynthesis) or via the oxidation of inorganic molecules (chemosynthesis)
* Referred to as producers

Heterotrophs

* Obtains organic molecules form other organisms (living and non-living)
* Referred to as consumers

Mixotrophs

* Certain unicellular organisms may on occasion use both forms of nutrition, depending on resource availability
* *Euglena gracilis* possess chlorophyll for photosynthesis (autotrophic) but may also feed on detritus (heterotrophic)

Types of heterotrophs

* Consumers
* Scavengers
* Detritivores
* Saprotrophs

Consumers (Types of heterotrophs)

* Herbivores: Eat plant matter
* Carnivores: Eat animal matter
* Omnivores: Eat both plant and animal matter

Scavengers (Types of heterotrophs)

Opportunistic consumer that feed on dead and decaying carcasses rather than hunting live prey

Detritivores (Types of heterotrophs)

Obtains nutrients from non-living organic sources, such as detritus and humus. Have internal digestion.

Saprotrophs (Types of heterotrophs)

Live on (or in) non-living matter, secrete digestive enzymes into it and absorbing the products of digestion (have external digestion)

How to measure the association between two species.

* Random sampling
* Throw a quadrat
* Put data is contingency table