Topic 2 - Ecosystems and Ecology Flashcards
Species?
A group of organisms sharing common characteristics that interbreed and produce fertile offspring
Habitat?
The environment in which a species normally lives
Niche?
Describes the particular set of biotic and abiotic conditions and resources to which an organism or population responds
Fundamental niche?
Describes the full range of conditions and resources in which a species could survive and reproduce
Realised niche?
Describes the actual conditions and resources in which a species exists due to its biotic interactions
Abiotic factors?
The non-living, physical factors that influence the organisms and ecosystems, e.g. temperature, sunlight, ph, salinity
Biotic factors?
The interactions between the organisms, e.g. predation, herbivory, parasitism, mutualism, disease and competition
What is a population?
A group of organisms of the same species living in the same area at the same time and which are capable of interbreeding
What are S and J population curves?
These are used to describe a generalised response of populations to a particular set of conditions (abiotic and biotic factors)
Limiting factors?
Factors which slow down growth of a population as it reaches its carrying capacity
Carrying capacity?
The maximum number of a species or ‘load’ that can be sustainably supported by a given area
Predation?
When one animal, the predator, eats another animal, the prey
Herbivory?
An animal (herbivore) eating a green plant
Parasitism?
A relationship between two species in which one species lives in or on another, gaining its food from it
Mutualism?
A relation between two or more species in which all benefit and none suffer
Community?
A group of populations living and interacting with each other in a common habitat
Ecosystem?
A community and the physical environment it interacts with
Respiration?
Conversion of organic matter into CO2 and water in all living organisms, releasing energy
Photosynthesis?
Produces the raw material for producing biomass
Trophic level?
The position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains
Producers (autotrophs)?
Plants or algae that produce their own food using photosynthesis and form the first tropic level of a food chain
Ecological pyramids?
Pyramids of numbers, biomass and productivity and are quantitative models, usually measured for a given area and time
Bioaccumulation?
The build up of persistent / non-biodegradable pollutants within an organism or trophic level because they cannot be broken down
Biomagnification?
The increase in concentration of persistent or non-biodegradable pollutants along a food chain
Productivity?
The conversion of energy into biomass for a given period of time
Net primary productivity?
Subtract respiration losses from gross primary productivity
Gross secondary productivity?
Total energy / biomass assimilated by consumers calculated by subtracting the mass of fecal loss from the mass of food eaten
Net secondary productivity?
Subtract respiration losses from gross secondary productivity
Maximum sustainable yields?
Equivalent to the net primary or net secondary productivity of a system
Energy subsidy?
Additional energy that we have to put into a system above that which comes from the sun (e.g. human labour, animal labour, fuel)
Biomes?
Collections of ecosystems sharing similar climatic conditions. Each will have characteristic limiting factors, biodiversity and productivity.
Zonation?
Changes in a community along an environmental gradient due to factors such as changes in altitude, latitude, tidal level or distance from shore
Succession?
The process of change over time in an ecosystem involving pioneer, intermediate and climax communities
Tricellular model of atmospheric circulation?
Explains the distribution of precipitation and temperature influencing biomes
Pioneer species?
First species to colonize an area - r strategists (can be plant or animal life)
Primary succession?
Occurs on a bare inorganic surface. Involves the colonisation of newly created land by organisms. It occurs as new land is either created or uncovered such as river deltas, after volcanic eruptions, on sand dunes.
Secondary succession?
Where an already established community is suddenly destroyed, such as following fire or flood or even human activity (ploughing)
