the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
What do organisms require in order to survive and reproduce?
Supply of materials :
from surroundings
other living organisms
What did animals in a community or habitat compete for?
food
mates
territory
Define the term interdependence
Within a community each species depends on other species.
If one species is removed it can affect the whole community
Examples of what organisms depend on each other for
Food
Shelter
Pollination
Seed dispersal
Define a stable community and effect on the population
where all the species and environmental factors are in balance.
population sizes remain fairly constant.
What do plants in a community or habitat often compete with each other for?
Light
Space
Water
Mineral ions
What are 'abiotic factors'?
non-living factors
What are 'biotic factors'?
Living factors
7 examples of abiotic factors
Light intensity
Temperature
Moisture levels
Soil pH & Mineral Content
Wind intensity & Direction
Carbon dioxide levels for plants
Oxygen levels for aquatic plants
4 examples of biotic factors that affect communities :
Food availability
New predators arriving
New pathogens
one species outcompeting another so the numbers are no longer sufficient to breed.
3 types of adaptations in communities :
Structural
Behavioural
Functional
Define what is meant by an adaptation
Features that enable organisms to survive in conditions in which they normally live in.
What are extremophiles?
Organisms that live in environments that are very extreme.
Example of extreme conditions :
High temperature, pressure, salt concentration
Examples of extremophiles
Bacteria that live in deep sea vents
Abiotic : Light intensity
light is required for photosynthesis
rate of photosynthesis affects growth of plant
plants can be food sources or shelters for other organisms
Abiotic : Temperature
temperature affects rate of photosynthesis as there are enzymes controlling photosynthesis
Moisture levels
animals and plants need water to survive
Soil pH and mineral content
soil pH affects rate of decay and how rate of mineral ions return to soil, then absorbed by plants.
different species of plants thrive in different nutrient concentration levels
Wind intensity and direction
wind affects the rate of transpiration
transpiration affects temperature of plant, rate of photosynthesis since it transports water and mineral ions to the leaves
carbon dioxide levels
carbon dioxide affects the rate of photosynthesis
affects the distribution of organisms as some thrive in higher carbon dioxide concentrations
oxygen levels in aquatic animals
levels of oxygen water vary
most fish need high concentration of oxygen to survive
Increase in food availability
organisms can breed more successfully and therefore populations increase
New pathogens
When a new pathogen arises in a population that has no resistance, so is wiped out rapidly
Competition
If one species is better adapted to the environment than another, then it will outcompete it until the numbers of lesser adapted species insufficient to breed