Biotic factors Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Biology — Higher

How do you extract information about a community from a chart, graph or table?

Identify what the labels, axes, scales or headings represent, including units, then read the relevant values.

How do you interpret community interaction data?

Compare values or patterns and relate them to a possible interaction between organisms. The conclusion must be supported by the data.

Does an association between changes in two populations establish that one caused the other?

No. An association alone does not establish causation.

When does competition occur between organisms?

When they need the same resource and its supply is limited.

Can competition occur between organisms of the same species, different species, or both?

Both: competition can occur within a species or between different species.

What does competition affect for organisms in a community?

Their access to resources needed for survival and reproduction.

What four resources do plants often compete for?

Light, space, water and mineral ions from the soil.

What three things do animals often compete for?

Food, mates and territory.

Does competition for mates occur within a species or between different species?

Within a species.

What can be used to suggest which resources organisms compete for in a habitat?

The organisms present and the resources available.

What does interdependence mean in a community?

Species depend on other species for resources or services.

What are four resources or services for which species may depend on one another?

Food, shelter, pollination and seed dispersal.

How can removing one species affect the wider community?

Changes in species that depend on it can have further effects throughout the community.

What is a stable community?

A community where species and environmental factors are in balance and population sizes remain fairly constant, though they may fluctuate.

What are biotic factors?

Living components of an environment that can affect organisms in a community.

How can a change in a biotic factor affect population size?

It can alter organisms’ survival or reproduction, changing the population size.

How can a change in food availability affect a population when food is limiting?

Less food may reduce survival or reproduction; more food may support a larger population.

What effect can a newly arriving predator have on its prey population?

It may reduce the prey population.

How can a new pathogen affect a population?

It may spread among susceptible organisms, reducing their survival or reproduction.

How can competition cause a species’ population to fall?

It can reduce the species’ access to resources.

How can a population decline lead to a species being lost from a community?

Too few individuals may remain to breed successfully.

How can a change in one population affect other species in a community?

It can affect other species that depend on that population.