topic 5 Flashcards
what is an abiotic factor?
physical and chemical factors e.g. climate and soil type
what is a biotic factor?
factors determined by organisms e.g. predation and competition
what is a habitat?
the place with a distinct set of conditions where an organism lives
what is a population?
a group of interbreeding individuals of the same species found in an area
what is a community?
the various populations sharing a habitat or ecosystem
what is an anthropogenic factor?
a factor arising from human activity, either biotic or abiotic e.g. deforestation or the introduction/removal of species from an ecosystem
what is primary succession?
starting in newly formed habitats, where there has never been a community before
what is a pioneer species?
the first organisation to colonise a habitat in primary succession. the only species that can cope with the extremes of temperature, and lack of soil, water, and nutrients e.g. lichen or algae
what is the pioneer phase of primary succession?
the first stage of primary succession. pioneer species begin to break up rock surfaces, allowing some organic material to accumulate, and begin making soil
what happens after the pioneer phase of succession?
wind-blown moss spores start growing, and build up more organic matter in the soil, which can then hold water. this development of soil allows seeds of small and shallow-rooted plants to germinate. this continues, with larger and taller plants arriving, and replacing the existing community
what is a climax community?
a stable community, usually dominated by trees. this typically has lower biodiversity than preceding stages as the dominant species outcompetes others
what is secondary succession?
on bare soil where an existing community has been cleared e.g. a ploughed field, or after a forest fire
what is deflected succession?
a community that remains stable only because human activity prevents succession from running its course e.g. sheep grazing in fields prevents it from developing into woodland
what is the primary productivity of an ecosystem?
the rate at which energy is incorporated into organic molecules in an ecosystem
what is an autotroph?
an organism that can make their own organic compounds from inorganic compounds (also known as producers) e.g. green plants, algae, and some bacteria
