Combined Biology - 4.7 Flashcards
What is an ecosystem?
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of the environment
What do organisms need to survive and reproduce?
A supply of materials from their surroundings and from other living organisms.
What do plants compete for?
- Light and space
- Water and mineral ions from the soil
What do animals compete for?
- Food
- Mates
- Territory
Within a community what does each species depend on other species for?
Food, shelter, pollinations, seed dispersal etc…
What happens if one species is removed from a community?
The whole community can be affected (known as interdependence)
What is a stable community?
One where all the species and environmental factors are in balance so that population size remains fairly constant
List abiotic (non-living) factors which can affect a community
- Light intensity
- Temperature
- Moisture levels
- Soil pH and mineral content
- Wind intensity and direction
- CO2 levels for plants
- O2 levels of aquatic animals
List biotic (living) factors which can affect a community
- Availability of food
- New predators arriving
- New pathogens
- One species outcompeting another (so numbers are no longer sufficient to breed)
What are adaptations?
Features of an organism enabling it to survive in the conditions in which it normally lives
How can adaptations be characterised?
- Structural
- Behavioural
- Functional
What are extremophiles and what examples of habitat may they live in?
Organisms which live in habitats which are extreme e.g. high temperature, pressure or salt concentration
Bacteria living in deep sea vents would be classified as what?
Extremophiles
For life on Earth, what are the producers of biomass?
Photosynthetic organisms
How can feeding relationships in a community be represented?
In a food web.