7.2 organisation of an ecosystem

producer

An organism that can make its own food.

How do producers make their own food?

photosynthesis

primary consumers

energy is transferred from producer to primary consumer

secondary consumer

An organism that eats primary consumers

transects use

-Used to study distribution of organisms along a line

transects steps

1. Mark out a line in the area you want to study using a tape measure

2. Then collect data along this line, either by counting organisms that touch the line or by placing quadrats along the line at regular intervals

quadrats

square frames (usually 1m x1m) used in estimating abundance in plants or slow-moving animals

quadrats practical

1-place quadrat on ground within 1st sample area

2-count all organisms within quadrat

3-repeat 1+2

4-calculate mean of number of organisms per quadrat

5-repeat steps 1-4 in 2nd sample area

6-compare means

stable community

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

carbon cycle examples

-co2 removed during photosynthesis by algae

-co2 returned when algae respire

-co2 returned when fossil fuels burnt(combustion)

carbon cycle definition

the movement of carbon from the nonliving environment into living things and back

water cycle

The continual movement of water among Earth's atmosphere, oceans, and land surface through evaporation, condensation, and precipitation

what is decomposition

the process by which chemicals are returned to the ecosystem from dead biotic matter

factors affecting decomposition

temp

water

availability of oxygen

how does temp affect rate of decomposition

chemical reactions work faster in warmer conditions, but if too hot enzymes can denature and stop decomposition

how does water affect rate of decomposition

Microorganisms grow faster in conditions with water as it is needed for respiration. Water also makes food easier to digest.

how does oxygen affect rate of decomposition

most decomposers respire aerobically

compost

decayed organic material used as a plant fertilizer.

methane gas

produced when microorganisms decompose waste anaerobically.

can be burnt as a fuel

decay practical

1. Measure out 5cm3 of lipase solution and add it to a test tube. Lapel tube with an 'L'

2. Add 5cm3 of milk to another test tube and add 5 drops of phenolphthalein indicator

3. Add 7cm3 of sodim carbonate solution to the milk to make it alkaline. The solution should be pink

4. Put both tubes into water bath set at 30oC and leave them to reach temperature. Check temp w/ thermometer

5. Then use a calibrated dropping pipette to put 1cm3 of lipase into milk tube and start stopwatch straight away.

6. Stir contents of tube with glass rod. The lipase will decompose the milk.

7. As soon as the solution loses its pink colour, stop the stopwatch and record the time.

8. Repeat three times. Repeat at a range of temperatures. Calculate means.

9. Use means to calculate rate of decay (1000/time) (units s-1)

temp effect on distribution of species in ecosystem

may lead to insects migrating to places in the world which are becoming hotter

water availability effect on distribution of species in ecosystem

populations may migrate to find water

atmospheric gas composition effect on distribution of species in ecosystem

certain pollutants can affect organisms, some plants cant grow

Biogas

A mixture of methane and carbon dioxide produced by bacterial degradation of organic matter and used as a fuel.

Biogas generators

Devices producing methane from organic waste.