4.1 & 2 Flashcards
Define ecosystem.
All living organisms and physical conditions in an area
What is the difference between community and population?
Community - all the organisms present in a habitat
Population - the number of organisms in a species
What are the 3 groups organisms in a community can be divided into?
Producers - organisms that make their own food (photosynthesis)
Consumers - organisms that cannot make their own food. They eat other organisms. (e.g. all animals are consumers)
Decomposers - group of consumers who gain energy through consuming dead or decaying material
How is energy transferred between organisms?
Producers gain energy and glucose through photosynthesis, organisms eat producers and increase biomass.
Define biomass.
Total mass of an organism in an area
Define trophic level.
Each step or level in a food chain.
What is the difference between food webs and chains?
Food webs - show interlinked food chains of the different consumers and producers
Food chain - only show organisms eating one food source during biomass transfer
Define the 2 factors which affect an ecosystem.
Abiotic - non-living (physical factors) components of an ecosystem (light intensity, temperature, moisture, soil pH)
Biotic - living components of an ecoststem (interaction of organisms)
How does light intensity affect communities?
Light needed for photosynthesis, more light more producers
How does temperature affect communities?
Temperature affects enzymes which control metabolic reactions.
Plants develop quicker in warm conditions due to high metabolism, as do cold blooded animals
How do moisture levels affect communities?
Lack of water = death of animals and plants
E.g. water is main part of blood plasma, plants wilt - water needed to keep cells turgid
Water needed for photosynthesis
How does soil pH affect communities?
pH affects biological activity in soil, and mineral availability.
Some plants prefer acidic conditions, some prefer alkaline soils.
