4.6 Understand the transfer of substances and of energy along a food chain.
Producer turns light energy into chemical energy.
The chemical energy takes the form of organic molecules Including
Carbohydrates
Proteins
Lipids
These molecules (food) are composed of Carbon to Hydrogen bonds
Carbon to Oxygen bonds
Carbon to Carbon bonds
Oxygen to hydrogen bonds
Carbon to nitrogen
These bonds represent energy.
But Carbon, Hydrogen, Oxygen and nitrate are substances/Matter.
So as the primary consumer consumes the producer, it begins to form these substances and contain the energy which was fixed from sunlight now in the form of chemical energy.
The Primary consumer consumes this for growth, respiration and life processes.
In turn the secondary consumer consumes the primary consumer which passes on the same molecules, reorganising them into Cheetah form and so on.
The substances and energy is passed on.
The food chain links the producer to the primary consumer to the secondary consumer and finally to the tertiary consumer
There is 1 organism per trophic level
Notice: in a food chain you cannot show an organism which is omnivore or an organism that's feeding 2 or more trophic levels.
Food chains show the flow of matter and the flow of energy.
b) Understand the concepts of food webs
Food webs allow us to provide a better description of the ecosystem.
The interaction the food web describes is feeding.
It allows us to show the organisms that are feeding at different trophic levels.
Feeding at different trophic levels has a number of consequences.
1. organisms can have multiple predators.
2. Feeding on multiple prey.
3. Food chain being linked
4.4 recall the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers.
Trophic = feed
Photosynthesis --------> Herbivore --------> Carnivore --------> Top Carnivore
Words used in ecology:
1. Producer - transforming light energy into chemical energy
2. Primary Consumer - Takes the chemical energy of the plant and turns it into chemical energy of the fly. It changes the form of the chemical energy
3. Secondary Consumer - " "
4. Tertiary consumer - Taking in the molecules from the secondary consumer and turning them into molecules suitable for the tertiary consumer.
At some point all of these die.After they are dead, they are broken down by a special group of organisms called DECOMPOSERS
e.g. Fungi and bacteria - important in the recycling of molecules often breaking down the complex molecules into nitrates and phosphates.
4.3 describe the use of Quadrates as a technique for sampling the distribution of organisms in their habitat.
We need to find the population of daisies:
Sample needs to be - Random (to avoid bias)
- Representative (Large enough) We need this and usually the bigger, the better.
about 10 quadrats must be placed or 10% of the area.
After you add up the number of daisies per meters squared in each Quadrat and divided it by the number of Quadrates.
this will give us the value which is the number of daisies per meter square.
You can also you this technique to compare the number of a species in different areas.
4.2 Recall the use of quadrats to estimate the population size of an organism in two different areas
Quadrats are a way of sampling different locations so that populations can be compared in the two different locations.
Sand dune ecosystem is made up of a number of populations which form the community and the habitat.
First thing to do to measure is to count by using a technique called quadrating.
A quadrat is made of squares made of any material and they form a square grid usually half a meter to half a meter.
It is used to sample eg. take samples from area A and count the number of individuals inside the grid. we will repeat this a number of times to get an estimate of the population size.
4.1 understand the terms: population, community, habitat and ecosystem.
Ecosystem = community of organisms and habitat.
Habitat
Abiotic factors = non biological factors of an environment.
1. Daylight and Dark
2. Temperature on local, seasonal or anual cycles
3. Rainfall
4.Humidity
5. Slope of the land etc
These are all non biological and so it would be a description of habitat.
Community of organisms
Population of different species interacting
Population = number of individuals of a particular species (each)
Species= organisms that reproduce to give fertile offspring.
Common interaction is feeding
Our Ecosystem is a community of organisms in a particular habitat. The community is made up of different populations of different species interacting within that habitat.
