ORGANISMS IN THEIR ENVIRONMENT
IMPORTANT DEFINITIONS IN ECOSYSTEMS 1- Ecosystem: A group of living organisms and their environment interacting with each other. 2- Community: All the dif ferent species of organisms that make up that are found in a given area. 3- Population: All that individuals of one species of an organism. 4- Habitats: The place in which organism live
AN ECOSYSTEM
FOOD CHAINS This is a series of organisms which feed of f of each other. A food chain starts with a producer and ends with a decomposer.
Producer: Plants Primary consumer: Herbivore (animal) Secondary consumer: Carnivore Tertiary consumer: Carnivore Decomposer: Bacteria/Fungus
Each step in a food chain is called a trophic level.
EXAMPLE OF A FOOD CHAIN
ENERGY LOSS IN FOOD CHAINS  1- in a food chain, energy is changed from one form to another.  For example, when solar energy is absorbed by plants, it is converted into chemical energy in food. Then, that plant will respire giving out energy as heat. Then, when the primary consumer eats the plant, it respires some of the plant losing some of its energy and also since it doesn’t eat every bit of that plant some of the energy remains in the plant. That means that the original solar energy was not completely passed from one trophic level to the next.
FOOD WEBS ď‚Ą A series of food chains interacting with each other.
MANIPULATING FOOD CHAINS IN THE FORMATION OF DATA A - pyramids of Numbers B- Pyramids of Biomass C- Pyramids of Energy
REMEMBER that the food chain begins at the base of the pyramid and ends at the apex!
A- PYRAMIDS OF NUMBERS Think about this food chain, Grass Antelope Leopard. Grass is the most in number and since it’s the beginning of the food chain, it makes up the base of the pyramid. The antelopes that eat the grass are less than grass in number, but more than the leopard, so they form the middle of the pyramid The leopard which is the last orga nism of the food chain is the least in number, therefore forming the apex
A- PYRAMIDS OF NUMBERS
A- PYRAMIDS OF NUMBERS Another example, Tree leaf eating insects insect eating birds birds of prey
SAMPLE QUESTION
B- PYRAMIDS OF BIOMASS These pyramids are built depending on the MASS of organisms. Tree leaf eating insects insect eating birds birds of prey
C- PYRAMIDS OF ENERGY Since energy is lost along the food chain, the pyramid will look like the following: Cabbage Snails Birds Birds of prey
THE WATER CYCLE
EXPLANATION OF THE WATER CYCLE The water cycle is made up of 3 main par ts: 1) Evaporati on: a) Water is lost from the sur face of water bodies such as Oceans, Seas….. Etc. b) Water is lost from leaves via TRANSPIRATION. 2) Condensati on: The process by which the water vapour is conver ted into clouds. This happens because in the sky the temp. is colder than on the sur face of the ear th. 3) Precipitation: The process by which the condensed water returns to the ear th in one of the following forms: a) Rain b) Hail c) Sleet d) Snow
THE CARBON CYCLE
EXPLANATION OF THE CARBON CYCLE There is a 0.04% carbon dioxide in the atmosphere A) USE OF CARBON: Plants use up the carbon dioxide for photosynthesis. The carbon is stored in the glucose that is made during photosynthesis. B) RETURNING CARBON : 1) Plants respire to return carbon in CO 2. 2) Animals eat the plants and then respire to return carbon in CO2. 3) Plants/Animals die and are decomposed by decomposers which return CO 2 by respiration. 4) Combustion of fossil fuels.
GLOBAL WARMING Too much carbon dioxide in the atmosphere results in the earth becoming warmer. (another gas that contributes to global warming is methane) This comes about as the result of the suns rays being trapped on the earths surface because of the dif ference in wavelength changes. You see when the suns rays descend to earth they come with a certain wave length, the moment they hit the earths surface, their wave length changes as the bounce back of f the earths surface. These waves can’t leave the earths surface because there is a blanket of co 2 trapping it. This results in the heating of the surface of the earth.
HUMAN INFLUENCES ON GLOBAL WARMING ď‚Ą 1) Deforestation: Humans cut down trees to make space or to use the wood for particular purposes. The less trees there are the less co2 that can be absorbed for photosynthesis.
ď‚Ą 2) Burning fossil fuels: just count how many cars you have in the garage and it will all make sense! Cars, Heating, Planes etc.
NITROGEN CYCLE
NITROGEN CYCLE EXPLANATION There is a 78% Nitrogen concentration in the atmosphere. Nitrogen is inert (unreactive) But….we need nitrogen to make amino acids and hence proteins. So how can we use this INERT gas? Easy look @ the next slide.
NITROGEN CYCLE EXPLANATION A) Making use of the Nitrogen: ď‚Ą Nitrogen can be used in one the following ways: 1) Lightning: the energy in a strike of lightning will cause force the nitrogen and oxygen to fuse into nitrogen oxides. These oxides are dissolved in rain water and are carried into the soil to form NITRATES. 2) Nitrogen fixing bacteria: these are found In the nodules of some plants like LEGUMES. This bacteria forces the nitrogen and oxygen to combine forming NITRATES. 3) Haber process: it is an industrial process in which nitrogen and hydrogen are made to react with each other to form AMMONIA. The ammonia is used to make fertlisers (example: Ammonium nitrates) Note: the Nitrates and the ammonia can then be taken up by the roots of plants. Plants then use these to make amino acidsďƒ proteins.
NITROGEN CYCLE CONT’D  Returning the Nitrogen: 1) Excretion of urea can return nitrates to the soil. 2) the death of an organism results in 2 types of bacteria playing a role in returning nitrogen a) Nitrifying Bacteria in the soil: returns the nitrogen stored in proteins to nitrates or ammonia in the soil. (This is useful for other plants ) b) Denitrifying Bacteria: Turns ammonia and nitrates back to nitrogen which is left to go into the atmosphere. Note: without the nitrogen cycle there is no chance of us getting any proteins.
POPULATION SIZE