Unit 1: Life on Earth
Ecosystems
Glossary
- Species: a group of organisms consisting of genetically similar individuals capable of breeding to produce fertile offspring.
- Biodiversity: the number of unique species in a given ecosystem.
- Population: the number of individual animals of one species in a given ecosystem.
- Producer: an organism which produces its own energy, such as a plant.
- Consumer: an organism which gains energy by consuming other organisms, such as an animal.
- Herbivore: an organism which consumes plant matter exclusively.
- Carnivore: an organism which consumes animal matter exclusively.
- Omnivore: an organism which consumes both plant and animal matter.
- Predator: a carnivorous animal that hunts other animals.
- Prey: an animal that is hunted or killed by another for food.
- Niche: An organism's role within its community (ecosystem). Usually describes the resources an organism requires, the conditions in which the organism can live, and the interactions it has with other organisms.
- Food Chain: a diagram depicting a series of organisms dependant on each other as a source of food.
- Food Web: a diagram comprised of interlocking, interdependent food chains.
- Biotic Factors: factors affecting an ecosystem which are caused by living things.
- Abiotic Factors: factors affecting an ecosystem which are caused by non-living things.
Competition
Competition between organisms is usually caused by a lack of resources (such as food or mates). Competition between organisms of different species is called interspecific competition, while competition between organisms of the same species is called intraspecific competition.
Distribution of Organisms
The distribution, or spread, of organisms describes where a specific species of organism can be found, either in the world or in a given ecosystem, and also how many individuals of that species can be found there.
The biotic factors which affect the distribution of species include:
- Competition for resources
- Disease
- Availability of food
- Grazing
- Predation
The abiotic factors which affect the distribution of species include:
- Light Intensity
- Moisture
- pH
Abiotic factors can be measured using light meter(s), moisture meter(s), and pH meter(s) on a given sample site.
Paired-Statement Keys
In order to identify an organism,paired-statement keys are often used. A paired-statement key is a series of pairs of questions, which direct you towards the name of the relevant organism, based on its features.
If the factors affecting a given area are too extreme, few or no species will be able to live there. As such, the more extreme conditions are in an area, the fewer species will survive there, in general.
Indicator species are species that can tell you about the quality of the environment by their presence or the lack thereof.