4.7 Energy efficieny

Energy efficiency uses a pyramid of energy. Much of the energy from the producer is lost throughout the food chain due to respiration, excretion and heat loss. All of the energy that we started with will come out when the organism dies and its body decomposes. This process of decomposing is done by decomposers.

4.6 Energy substances in food chains

The producer in the food chain converts sunlight into chemical energy. The chemical energy then takes the form of organic molecules such as Carbohydrates, Proteins and Lipids. Consisting of bonds such as :

C-H

C-O

C-C

O-H

C-N

C H O N substances all contain energy. The energy is passed on along the food chain and adjusts to each animal.

4.5c Pyramids

There are 3 different types of food pyramids:

-Pyramids of number

-Pyramids of biomass

-Pyramids of energy transfer

Pyramids of number:

These pyramids illustrate the number of organisms per trophic level, however there are problems with using this method. The pyramids sometimes goes against the laws of thermodynamics and fails to show the energy transfer between trophic levels. They can be effective but are highly limited.

Pyramids of biomass:

Bio=living and mass=g/kg

Biomass is based on dry mass and tends to be measured in kg/area. It is difficult to find out the dry biomass of each organism per trophic level.

Pyramids of energy transfer:

This measures the movement of energy from on trophic level to another. It follows the laws of thermodynamics and cannot be inverted. It is measured in Joules or KJ/m squared/time (seconds/minutes/years). This method is also extremely hard to calculate.

4.5b Food Webs

The food webs of the ecosystem describe the feeding interaction within a community. It shows organisms feeding at different trophic levels. Organisms can have multiple trophic levels, they can also have multiple prey, multiple predators and everything becomes linked. In many cases, animals can both be primary and secondary consumers.

4.5a Food Chains

The food chain connects the Produce-> Primary Consumer-> Secondary Consumer-> Tertiary Consumer

There is 1 organism per trophic level

The food chain shows the flow of matter and energy

4.4 Trophic Levels

-Trophic means to feed

Photosynthesis Herbivore Carnivore Top Carnivore

Producer Primary Consumer Secondary Consumer Tertiary Consumer

Light energy-> Plant chemical energy-> Chemical energy-> Chemical energy->

chemical energy animal chemical energy Chemical energy Chemical energy

All organisms die and are then broken down my decomposers eg. Funghi and bacteria. These break down complex molecules into nitrates and phosphates.

4.3 Quadrates samples

Wes use quadrates to find the population of certain species, in this case daisies. The sample must be random so there is no bias. It must also be representative.

The sample has to be large enough so that the estimate of the population is as close as possible to the real population.

4.2 Quadrates

The image shows a Sand Dune ecosystem which is made up of a number of populations which form the community and the habitat.

There is a fence which splits the Sand Dune region into grazed by cattle and ungrazed.

So there are two different types of areas within an ecosystem and we can choose to study both populations.

The first step is to count the number of individuals in the population. The technique used to do so is called quadratic. Quadrates are made up of squares and can be produced in any material such as wood, metal or string forming a square grid.

These square grids are used to sample the populations of different areas. By counting the number of individuals in the grid, and repeating this numerous times, we are able to gain an estimate of the population.

4.1 Ecosystems

An ecosystem is a community of organisms in a particular habitat.

The study of habitat is non biological (abiotic factors) eg:

-Cycle of daylight/dark (photo period)

-Temperature (local/seasonal/annual)

-Rainfall

-Humidity

-Slope of the land

The community is made up of populations of different species and their interacting with each other. Population is the number of individuals of a particular species. Species are organisms that reproduce to give fertile offspring. The main type of interacting is: Feeding.

Summarise:

Ecosystem-community of organisms in a particular habitat-community of different species interacting.