Ecosystems Flashcards
What are biotic factors affecting ecosystems
Competition and consumption, Eg Living organisms
What are abiotic factors affecting ecosystems
Temperature: Enzyme activity, thermoregulation, leaf-fall and flowering (in plants)
Photosynthetic rate (in plant) eg light
What is a trophic level
A stage in a food chain
List the names of a food chain with 5 stages
Producer-primary consumer-secondary consumer-tertiary consumer-quaternary consumer
What is a producer
An organism (eg a plant) that converts light energy to chemical energy (ie autotrophic nutrition)
What is a consumer
An organism that gains energy by feeding in other organisms (ie heterotrophic nutrition)
What is procedure, adv and disadv of measure of fresh (wet) biomass
Procedure: living organisms measured
Adv: no organisms are killed
Disadv: presence of water reduces accuracy
What is procedure, adv, disadv of measure of dry biomass
Procedure: organisms are killed and heated at 80^C until all water removed
Adv: estimates of mass are more accurate
Disadv: organisms must be removed from ecosystem and killed
When might a pyramid of biomass not be a pyramid
When the consumer is usually large but in small number Eg trees may be few in number within an ecosystem, but their total biomass will still be greater then that of primary consumers
What transfer occurs at producer level and consumer level
Producer: light energy conveyed to chemical energy in producers
Consumer: stored energy in biomass of one trophic level is transferred to next trophic level by consumption
What is some energy not transferred at producer and consumer level
Producer: most light energy (90%) cannot be absorbed by plants. Some energy used in reactions of respiration and bud not converted to chemical energy in biomass
Consumer: some parts of organism (eg bones, roots, feathers) are inedible or indigestible. Some energy lost from food chain as heat, through movement or urine
What is the calculation formula for producer and consumer levels
Producer: net production=gross production - respiratory losses
Consumer: ecological efficiency= (energy available after transfer/ energy available before transfer) X100
How can humans manipulate factors in the production of plants
Light: plants grown in greenhouses under optimal light intensity and duration, seed sowing times to maximize leaf area present for photosynthesis during brightest months of year
Temperature: greenhouses provide regulates optimal temps
Water: irrigation, genetically engineered to drought resistant crops
Nutrient levels: fertilizer
Pests: pesticides
How do humans manipulate the efficiency of energy transfers to primary consumers
Movement: movement of farm animals limited. More energy channeled into growth
Disease: antibiotic use reduces energy expenditure in immune systems
What is decomposition
Process of large organic molecules (in dead animals and plants) being broken down into smaller inorganic molecules
