This is because apparently we can all fail IGCSE if I give you resources and stuff...I don't really understand it but yeah...better safe than sorry...So...please after this post. If you share the link do it privately...and password too!!
Thank you.
Anyone who fails to follow...I'm afraid I'll have to close all access to this site for everyone :(
I don't wanna fail... ._.
-.- Who does?
Sorry. And thanks xD
-mirunae
PS-YOU DO NOT KNOW MY NAME EITHER. I AM MIRUNAE! MIRUNAE!
:D
KEYWORDS-
Producer - Producers are usually plants, they are organisms which produce food directly with sunlight with processes such as photosynthesis.
Ecosystem - All of the species of organisms living in an area as well as things that affect them. This could be the soil or the weather. An ecosystem will include all the interactions between all the living organisms and the components of their habitats.
Consumer - Consumers get energy by eating plants and other animals.
Environment -
Community -
Population -
Decomposer -
Habitats -
Community -
Autotroph -
Heterotroph -
Pyramid of number -
Pyramid of biomass -
Pyramid of energy -
Organisms and their Environment-
4.1 - understand the terms population, community, habitat and ecosystem.
Population - The number of a particular species living in an ecosystem at one time.
Community - The populations of all organisms living in an ecosystem at one time. (Made up of different populations of different species)
Habitat - The homes of where specific organisms live - features are all non-biological
Ecosystem - A community of organisms interacting with each other with and in their habitats. (Contains organisms of many kinds that interact through feeding relationships.)
4.2 - explain how quadrats can be used to estimate the population size of an organism in two different areas.
Quadrats can be used to estimate the population of organisms in their habitats in different areas.
Choosing to study the population of two different areas in the same ecosystem would mean you would have two different areas in the same ecosystem that are separated by fencing and such. We could choose to count the population in each area.
If you had 2 areas. For example, a sand dune with grazed and ungrazed grass, and you want to estimate the population. You can do so by using quadrats.
To do this, you would sample the area on both sides, placing you quadrat (made of any material, a perfect square) on the ground and counting the population. You would repeat this many times to get an estimated population size of the organisms in two different areas which can then be compared.
4.3 - explain how quadrats can be used to sample the distribution of organisms in their habitats.
http://www.youtube.com/watch?v=64NOXf-N-aY
Like in the last point, you can use quadrats to sample the population of organisms in their habitats.
You can try daisies in sand dunes, bugs in your garden or whatever.
However, the sample has to be non bias...as in you can't pick an area to just place your quadrat...cuz then you lazy people will pick areas with no organisms cuz you ain't bothered to count!
-RANDOM (Non-biased)
-Representative (sample large enough so that the estimate is as accurate as possible [AASP haha] The bigger the better)
To do this, you would have a grid system across the ecosystem area. Then you need random numbers (to be non bias) which can be generated randomly from anywhere...use your calculator! This is to obtain the x-coordinate and y-coordinate.
With this, you can then place your quadrat! Try to cover about 10% of the AREA. Then you record this data in a table...with quadrat number and the number of organisms in that quadrat...
Then you add it up, and divide by the number of quadrats... so the mean. And that's the estimate of the population!
Feeding relationships
4.4 - explain the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers.
http://www.youtube.com/watch?v=Ua_ZKHPvqSw
Tropic levels are food levels...so
A producer produces it's own energy using sunlight with processes such as photosynthesis, the primary consumers eat the producers to convert energy for itself. The same happens with the secondary consumer eating the primary consumer and the tertiary consumer eating the secondary consumer.
Decomposers are like the beggars.These are fungi and bacteria, they are important in the recycling of molecules - they break down and decompose dead material and waste products to recycle the nutrients.
4.5 - understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer.
Food chains - food chains are the MOST simplest ones...You have only 1 organism per trophic level. They show the flow of matter and energy...cuz you know they're always converting energy. (I'm surprised...is there such thing as an energy war? O_O)
Food webs - much better description of the ecosystem. (Community of organisms that interact.) Allows us to see the different trophic levels of organisms feeding.
-multiple predators
-feeding on multiple pray
-linked food chains = food web (easy, no?)
Pyramids - (LoL...Listen to the song by Charice xD Asians ftw.)
Pyramids of numbers - representing the numbers of organism at each trophic level. Shows more than who's eating who. (Basically, made of counting the number of organisms at each trophic level)
So...if cows eats a lot of grass and then I (a mirunae) eat a lot of beef and then bears eat mirunaes then...
This can also show the percentage of energy being converted by each organism at each trophic level.
Another thing could be...1 tree and many creature feeding from that tree...but...this cannot show the energy levels as there is no way to increase energy as we can create energy! We can only convert energy. This can represent number but not energy levels.
Pyramid of biomass - the biological matter that makes up an organism - based on dry mass. Mass of matter passed from 1 trophic level.
It is difficult to calculate as it is the dry mass...NO WATER :O You gotta like dry everything haha. -.-
Biomass gets less at each level because:
-Plant roots and animal bones are not eaten.
-POO. Is not digested. Fibres. (FAECES)
-PEE. Some break down but then are not used. (URINE/UREA)
-Some is used up in respiration.
-Only a little bit is used for growth and new body mass which makes up the biomass.
Pyramid of energy transfer - how one energy is transferred from one trophic level to another.
Sunlight at 100%
Producer at 10%
Consumer 1 at 1%
So...it gets less...the energy that's there.
You could draw it like the pyramid of number...with 10% of the preceding tophic level energy used by the next.
This is time consuming and bothersome. Just use the number one -.- It's WAYYYYY easier.
4.6 - understand the transfer of substances and energy along a food chain.
When the producer converts light energy to chemical energy in the form of organic molecules. C, H, O, N (remember? :D :D :D AGENT CHO! and N of VIXX :D :D :D) These molecules are also food for the thing that eats the producer and the thing that eats that. Energy is used for respiration and such too. The energy is in the bond.
C-H
C-O
C-C
H-O
C-N
When photosynthesis takes place it produces the molecules...then when it gets eaten these molecules are also transferred and are used for respiration. Substances, matter and energy (within the bonds) are transferred.
4.7 - explain why only 10% of energy is transferred from on trophic level to the next.
Only -10% is transferred cuz y'know, every living thing gotta do what it's gotta do. (Quoting someone from law class today...A man's gotta do what a man's gotta do when he has to do it. haha) Yes, energy is lost in poo and then you use it up for respiration and stuff so the thing that eats you only get 10% of your energy...
(WORTH IT? haha. But then everyone gets only 10%! So it's fair.)
Sooo...
100kJ -> 10kJ -> 1kJ
And then you die. What a sad life.
Cycles within ecosystems-
4.8 - describe the stages in the water cycle, including evaporation, transpiration, condensation and precipitation.
Oh! Remember the song? Goes up as evaporation, comes together as condensation, comes down as precipitation, yes it does!
Youtube it! It will help you remember!~ http://www.youtube.com/watch?v=QJdKdtA9aeE <LINK :D :D :D
THE WATER CYCLE SONG :D :D :D
TRANSPIRATION - when plants take water in through their roots and then it is evaporated from the leaves
4.9 - describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition and combustion.
photosynthesis
Carbon dioxide + water -photosynthesis/chlorophyll/light> glucose and oxygen
This reduces carbon dioxide levels in the atmosphere.
Feeding
Eats and converts energy to be used. Carbon passes along the food chain.
Respiration
glucose + oxygen -> carbon dioxide + water and energy
-Adds carbon dioxide to the atmosphere.
-All organisms put co2 into atmosphere with this process.
Decomposition
All organisms will die! And then the decomposers break the organic molecules that remain. This will result in release of CO2 back into the atmosphere.
Combustion
Fossil fuels from the remains of animals, as oils and fuels - these are combustable and by doing so, this releases CO2 into the atmosphere.
It may also occur naturally, with lightning or forest fires.
So you have carbon dioxide in the air...plants take it in...they die or are eaten...by animals who respire animals die...and decomposers turn that into co2 and then...it's also fossilized creating fossil fuels.
4.10 - describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria.
nitrogen fixing bacteria - exist in root nodules of leguminous plants and they make ammonia which plants use to make amino acids.
decomposers - they turn dead molecules into ammonia.
nitrifying bacteria - they oxidise ammonia into nitrates in the soil in a process called nitrification.
denitrifying bacteria - they break nitrogen in soil down into nitrogen gas.
nitrogen fixing bacteria in leguminous plant nodules make ammonia while lightning can allow there to be nitrates in soil, ammonia is then oxydized by nitrifying bacteria into the soil. Fertilizers can be used to put nitrates into the soil as well. This is then absorbed by plants which are eaten and such by animals that die and decompose which can create ammonia as well. The denitrifying bacteria breaks nitrogen down into nitrogen gas. Animal excretion also contains nitrogen - urea.
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