Unit 7 - Ecology Flashcards
What do organisms compete for?
Space, territory, mates, food, light
What are abiotic factors?
Factors which are non-living, such as soil, light etc.
What are biotic factors?
Factors which are living, such as disease (pathogens), predators etc.
How do we sample an environment?
Placing a quadrat in random locations (via random number generator), and count organisms in each square. Multiply amount by area to estimate population. Using a transect allows for changes in population density to be measured
What do food chains show?
The direction of biomass and therefore the transfer of energy between organisms.
What are the different labels given to organisms in the food chain? (Trophic levels)
Producer - an organism which gets its source of energy from the sun, eg grass
Primary consumer - a herbivore or omnivore which eats the producer
Secondary consumer - an omnivore or carnivore which eats the primary consumer
Tertiary consumer - an omnivore or carnivore which eats the secondary consumer
Why do farmers use the the process of decomposition?
They use decomposition to produce natural fertilisers to grow crops, or to produce methane gas which is used as a fuel.
What is biodiversity?
The variety of species that exist within an ecosystem. Higher biodiversity makes a more stable ecosystem as organisms are dependent on other species.
What are extremophiles?
Organisms which live in extreme conditions of temperature, salt, pH or pressures.
How do we work out organisms in an area from a sample size?
Total population size = total area/area sampled x number of species in sample
What are the optimum conditions for decomposition?
Warm - enzymes involved in decomposition work best when in warm conditions (but not too hot otherwise they become denatured)
Moist - many chemical reactions in decay require water
Oxygen levels - decomposers carry out aerobic respiration which requires oxygen
Also an increased surface area helps decomposers act faster
What happens if the decomposers respire anaerobically?
Anaerobic respiration results in methane (biogas) being produced.
