b4 - community level systems

ocr gateway dosnt include detailed descriptions of water,carbon and nitrogen cycle

what are 4 examples of materials which are recycled through componenents of an ecosystem

1. water
2. carbon
3. nitrogen
4. oxygen

what are decomposers

microorganisms which break down or decay dead organic material as well as animal waste

what happens during decomposition

nutrients are released back into the soil to be recycled

what are some of the organisms that help in decomposition

bacteria and fungi

what are the three factors affecting decomposition rate

1. temperature
2. water
3. availability of oxygen

how does temperature affect the decomposition rate

Chemical reactions generally work faster in warmer conditions, but if it is too hot the enzymes in the bacteria can denature and stop decomposition.

how does water affect the decomposition rate

• decomposing microorganisms need water for chemical processes

• less water available, the slower these chemical processes will be

how does availability of oxyegn affect the decomposition rate

• decomposers respire aerobically so lack of oxygen forces microorganisms to respire anaerobically

• anaerobic decay is slower and less efficient

why does carbon need to be recycled

because theres only a set amount of carbon in the world

whats a community

the population of different species living in a habitat

whats a population

the number of a particular organism within an area

whats a habitat

a natural home or enviroment of an organism

whats an ecosystem

the interaction of a community of living organisms with the non living parts of the environment

whats distribution

how an organism is spread out in a given area

whats competition

an interaction between organisms or species in which they both try to use the same limited resources.

whats interdependance

idea that all organisms in an ecosystem depend upon one another

whats an abiotic factor

non living parts of an enviroment (e.g. soil PH)

whats a biotic fcator

living parts of an enviroment (e.g. snail)

whats a stable community

the species and environmental factors are in balance so that the population sizes remain fairly constant

what are the abiotic factors affecting communities

1. light intensity
2. temperature
3. moisture levels
4. soil ph and mineral content

how does light intensity affect communities

● Light is required for photosynthesis.

● The rate of photosynthesis affects the rate at which the plant grows.

● Plants can be food sources or shelter for many organisms.

how does temperature affect communities

temperature affects the rate of photosynthesus

how does moisture levels affect communties

Both plants and animals need water to survive

how does soil ph affect communities

Soil pH affects the rate of decay and therefore how fast mineral ions return to soil (which are then taken up by other plants).

what are biotic factors affecting communities

1. food availability

2. new diseases

3. new predators

how does food availability affect communties

more food means organisms can breed more successfully and therefore the population can increase in numbers

how do new predators affect communities

if the number of predatoes decreases, then the number of prey might increase because fewer of them will be eaten

how do new diseases affect communities

when a new pathogen arises the population has no resistance to it so they can be wiped out quickly

what are the 3 types of interdependence

1. mutualism

2. parasitism

3. predation

whats mutualism

when two species can interact and mutually benefit from each other

whats parasitism

rekationship between two organisms where in one organism (the parisite) thrives at the cost of the other (the host)

whats predation

where one organism, the predator, kills and eats another organism, its prey

what are 4 things animals compete for

1. mates

2. space

3. food

4. water

what are 4 things plants compete for

1. light

2. minerals

3. water

4. space

how is a food web different to a food chain

• they are effectively multiple food chains combined

• food webs show all interactions between the species in the community

why is the recycling of nutrients important

if they weren’t recycles there would be used up and there wouldn’t be any left for future organisms

what are producers

● E.g. plants and algae

● They make their own food by photosynthesis.

what are consumers

organisms that consume other organisms for their energy

what are primary consumers

consumers that eat producers

what is a secondary consumer

organisms that eat primary consumers.

what are tertiary consumers

• organisms that eat secondary consumers

• They have no predators and are at the top of the food chain