Energy and Ecosystems Flashcards
Define Population
Group of organisms of the same species, living in the same place at the same time
Define Community
All of the organisms, of several or all species, living in one location at one time
Define Ecosystem
A balanced biological system where all the organisms and the non-living components with which they interact in a particular location. Energy flow and nutrient cycling within the ecosystem.
Define Habitat
The place where an organism live. It provides the correct set of environmental conditions
Define Niche
The role of a particular species in its ecosystem, including its microhabitat, feeding and breeding behaviour etc.
Define Producer
An organism which uses light energy (or that from the oxidation of minerals) to fix atmospheric CO2 into complex organic molecules (chemoautotroph or photoautotroph
Define Consumer
Organism which derives its energy and complex molecules from the tissues of other living things (heterotroph)
What is a biotic factor?
A living component of the ecology of an organism
What is an abiotic factor?
A non-living components of the ecology of an organism
What is a Edaphic factor?
Aspects of the soil which affect the ecology of an organism
Describe what a food chain is?
A diagram which shows a simple, un-branched, feeding relationship, usually with only one organism at each position (trophic level)
Describe the three trophic levels?
The position of an organism in a food chain
T1 is always a producer, usually a plant
T2 is a primary consumer = a herbivore
T3 is a secondary consumer = a carnivore
What three things do food chains not show?
1) All the species at each trophic level (eg insect herbivores), so the calculated efficiency of energy transfer is low.
2) detritivores and decomposers which are often a greater biomass than other consumers
3) omnivores or other species feeding at several trophic levels
What type of diagram shows some things a food chain cannot?
a Food web
What is the initial energy source for most ecosystems?
The Sun
What happens to light energy from the sun?
Light energy is trapped as chemical energy by photosynthesis
Define Gross Ecological Efficiency
This is the percentage transfer of the energy from one trophic level to the next
Define Photosynthetic efficency
This is a measure of how well a plant is able to capture light energy
How do you calculate Photosynthetic efficiency?
(Gross Primary Productivity / Quantity of light energy falling on plant) X100
What is the typical value of Photosynthetic Efficiency?
1-2%
Whys is the typical value of photosynthetic efficiency typically so low?
- Much light is reflected from the leaves.
- Some light passes through the leaves.
- Some light is absorbed by non photosynthetic parts.
- Much of the light is of the wrong wavelength (plants absorb blue and red wavelengths best).
Define Gross Primary Productivity (GPP)
is the rate of production of chemical energy in organic molecules by photosynthesis in a given area.
What is the units for GPP?
kJ m-2 year-1
Define Net Primary Production (NPP)
Amount of energy in organic molecules available in plants for herbivores or primary consumers. This represents the potential food available to primary consumers.
