species and ecosystems Flashcards
Species
a species is a group of organisms that can potentially interbreed to produce fertile, viable offspring
population
a population is a group of organisms of the same species that are living in the same area at the same time
community
a community is a group of population 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
Species two ways of method of nutrition
1) autotrophs
2) Heterothrophs
Autotrophs
- Synthesises its own organic molecules from simple inorganic substances (e.g. CO2, nitrates)
- Energy for this process is derived from sunlight (photosynthesis) or via the oxidation of inorganic molecules (chemosynthesis)
- Because autotrophs synthesise their own organic molecules they are commonly referred to as producers
Heterotrophs
- Obtains organic molecules from other organisms (either living / recently killed or their non-living remains and detritus)
- Because heterotrophs cannot produce their own organic molecules and obtain it from other sources, they are called 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)
Nutrient cycling
The supply of inorganic nutrients is maintained by the nutrient cycle
three components required for sustainability in an ecosystem
1) Energy availability
2) Nutrient availability
3) Recycling of wastes
Mesocosms
Mesocosms are enclosed environments that allow a small part of a natural environment to be observed under controlled conditions
Quadrat sampling
placing a rectangular frame within a defined area and counting the number of species (individual) present in the area
