Recall the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers. 

- Word "Trophic" means to feed, so we are looking at the names given to the different feeding levels.

- A carrot plant here is doing photosynthesis. The carrot fly is eating parts of the carrot plant because it is a herbivore. And the Flycatcher is eating the carrot fly because it is a carnivore. And a carnivore eating another carnivore makes it the Top Carnivore because it is at the top of the food chain.

- Other names exist used in ecology are given to each level.

The Carrot Plant = Producer (turning light energy into chemical energy)

The Carrot Fly = Primary Consumer (taking in the chemical energy of the plant, and turning it into chemical energy of the fly.

The Fly Catchers = Secondary Consumer (eats the primary consumers - changing chemical energy from one form to another)

Top Carnivore = Tertiary Consumer (eats the secondary consumer - changing chemical energy from one form to another)

- All of these organisms at some point will DIE, at which point they are broken down by organisms called Decomposers

Examples of Decomposers: Fungi and Bacteria

They are important in the recycling of molecules - often breaking down the complex molecules into nitrates and phosphates.

Describe the use of Quadrats as a technique for sampling the distribution of organisms in their habitat

- Going to use Quadrats to take the population of daisy's on each side; grazed and ungrazed.

Sample has to be random so it's not biased, and it also has to be representative. Because of this we have to take a sample large enough that our estimate of the population will be as close to the true population as possible.

- The easiest way to do this is to plot a grid on a drawing/map of the land. Then have some random numbers to generate the x and y values. Lets say for example the numbers generated are (x, y) 3, 3

- Then the Quadrat will be placed at the coordinate 3, 3. Then the number of daisy's in that Quadrat must be counted and put into a table.

- This is 1 Quadrat done, but to get the best and most reliable results we would ideally want 10 Quadrats done. or more accurately at least 10% of the actual area of the land.

- Once the 10 Quadrat values have been put into a table then we would add up the number of daisy's and divide by the number of quadrats. This would give us the value of the number of daisy's per meter square.

Recall the use of Quadrats to estimate the population size of an organism in two different areas


- This is a photo of a Sand Dune Ecosystem which is made up of a number of populations which form the community. The habitat is shown below and is split in two different areas by a fence. One side which is grazed by cattle and one side which is ungrazed.

- So we have to different areas within an ecosystems and could choose to study the population on either side. We could do this by counting the number of individuals in the population. The technique is called 'Quadrating.' Based on squares hence the word "Quad". These squares can be made of any material (wood, string, metal) to form a square grid.

- The Quadrat is used to take a sample of the population in a selected area. This is done by laying down the Quadrat and counting the number of individuals inside the square. If this is done for every square in the area, it can be used to gain an estimate of the population size.

- To summarise Quadrats are a method of sampling different locations so populations can be compared.

Understand the terms: Population, Community, Habitat and Ecosystem

An Ecosystem is a Community of Organisms in a particular Habitat. The Community is made up of different populations of the different species interacting within that habitat.

- Habitat includes all the "Abiotic" factors (non biological factors)
eg. cycle of daylight with dark, temperature (local or seasonal), rainfall, humidity, geology (slope of the land)

- Community of Organisms is made up of populations of different species and they are all interacting.
Population is the number of individuals of a particular species.
And species are organisms that reproduce to give fertile offspring.