B17 - Organising an ecosystem Flashcards
What do all food chain start with ?
A producer
Why are producers extremely improtant to a food chain ?
-They SYNTHESISE complex MOLECULE .
(Green plant make GLUCOSE by PHOTOSYNTHESIS with energy from the sunlight .)
What are molecules like glucose known as ?
-Known a Biomass , and these are molecules pass down a food chain to toher organisms .
-So producers are the source of all the biomas in a community , which is why they are important .
What are primary consumers ?
Organims that eat the producers .
What are secondary consumer ?
-Animal that eat priamry consumers .
What are Tertiary conumers ?
Eats secondary conumers .
What are predators ?
Consumers that kill and eat other animals .
What are prey ?
Animal that is being eaten .
What does the grpah show ?
The graph shows the populations of predator and prey in a community . (Will see a similar graph for any predator and prey .)
What is they key idea of the graph ?
The nuber of predator and prey rise and falls in cycles .
EXPLAIN they key idea of the graph with an example .
Foxes and rabbits e.g
-Warm Summer , lots of grass for rabbits to eat meaning rabbits offspring survive and rabbit poulation increases .
-Now the foxes have MORE , rabbits to eat , so after sometime , the fox population alo INCREASES .
-hOWEVER , as there are more foxes thaan rabbits , means more rabbits iwll be eaten , so population of rabbits falls . )
-Now foxes have fewer rabbits to eat so less foxes , so rabbits survive and population of rabbit tart to increase , but thi means foxe have more to eat so their populatrion rise .
When is this key idea only true ?
In a table community - where all the biotic and abitoic factor are in balance .
How can the prey predator cycle change ?
-If omething like a drought , disease , new predator , then the prey cycle will start to change .
Where does the carbon cycle start ?
It start with carbon dioxide in the atmosphere .
What is the ONLY WAY carbonc an enter the carbon cycle ?
Through photoynthei , (In photoyntheisis , carbondioxide i combined with water to make sugar and glucose . Photosynthesis also ues light energy and is carried out by plants .)
How does carbondioxide reutrn back into the atmospherre ?
By respiration - carried out by every single living organism .
What is stage one of the carbon cycle ?
Plant and algae take in carbon dioxide from the atmosphere in photosyntehsis . The carbon is used to make carbohydrate , fats and proteins , which make up the cells in plants and alage .
What is stage two of the carbon cycle ?
Plants and alage respire , so some of the carbon is released back into the atmosphere as carbondioxide .
What is stage three/ stage four of the carbon cycle ?
Plants and alage can be eaten by animals , and these animals can be eaten by other animals .
-At this point the carbon in the plants , bcomes part of the cabrohydrates fat and proteins in the cells of animals .
What is stage five of the carbon cycle ?
Animals also respire , so ome of the carbon is releaed back as carbondioxide .
What is stage six of the carbon cycle ?
Animal release waste products such as faeces .
-Eventually all plants and animals die .
What is stage seven of the carbon cycle ?
Now we have carbon in waste product and dead remains. The waste product is broken down by decomposing material like bacteria and fungi .
What is stage seven.5 of the carbon cycle ?
When decomposers carry out respiration , the carbon in the waste and dead remain is returned to the atmospehre as carbondioxide .
Why are decomposer important ?
-As they ccle material through an ecosytem .
-As well a returning carbon to the atmospehre as carbondioxide .
-They alo release mineral ions into the soil .
What is stage eight of the carbon cycle ?
Under certain condition (Lack of oxygen ) decompoer cannot function effectively .
-If this happen then the carbon in the dead remain can slowly be converted into fossil fuel .
-Over millions of year ago , a large amount of carbon ha been trapped underground as fossil fuels .
What is stage nine of the carbon cycle ?
Howveer , over the alt 200 years , humans have been burning , huge amount of foisil fuels , for example coal and oil .
-Combusting fossil fuels is releasing a large amount of carbon dioxide back into the atmosphere .
Stage one of the watercycle
-Almost all the water on Earth is found in the oceans , this is saltwater .
-Energy from the sun casues this water to evporate from the surace of the sea .
Stage two of the watercycle
-The water vapour now travels into the air nad coolds down .
Stage three of the watercycle
-When it cools , the watervapour condenses to form clouds .
Stage four of the watercycle
-The water in clouds then falls to the ground as percipitation .
-Precipitation includes rain andsnow as well as halt and sleet
KEY IDEA aout precipitation
-All forms of precipitation contains freshwater , (no salt )
Stage five of the watercycle
-Once the water hits the ground , some of it simply evporates back into the atmosphere as watervapour .
Stage six of the watercycle
-Some of the water passes through the roots and forms aquifers .
Stage seven of the watercycle
A lot of the waater forms rivers and streams .
Stage eight of the watercycle
The water in rivers and streams eventually drains back into the sea .
How do plants play a role in the water cycle ?
-Plants take up water in the roots , and the water moves up the plant in the xylem , and passes out of the leaves through the stomata as watervapour (TRANSPIRATION)
How do animals play a role in the water cycle ?
Animals take in water by drinking it and in food , animals release water in their urine ,, faeces and when they exhale .
What do decomposers do ?
-Carry out decomposition of wasye materials and dead remains .
-As well as returning carbon into the atmosphere , decomposers also return mineral ions back into the soil .
What is compost explained (1)
-Compost heap is often found in gardens and farms .
-Gardeners put dead plant matrail such as grass onto the compost hep .
-Overtime , bacteria and fungi decompose the plant material to produce compost .
What is compost explained (2)
-Gardeners and farmers then use he compos as a natural fertiiser . As compost is very rich in minerals that plants need to grow .
Three factors that effect the rate of decompostion ?
-Temperature
-Amount of water
-oxygen .
How does the temperature effect the rate of decompostion ?
-Decompostion takes place FASTER at warmer temperatures .
-As decomposers use enzymes to breakdown plant material these enzymes work faster in warm conditions .
What is the temperature like in compost ?
-Compost heaps tend to be warmer anyways .
-That is because decomposers release energy when they carry out aerobic respirtion .
-However , if the compost gets too hot , the enzyymes and decomposers can denautre and the decomposers can die .
How does the amount if water effect the rate of decompostion ?
-Decomposing microrganisms work faster if the compost is mosit .
-As many of the chemical reactions in decay , require water .
-So its important gardeners do not alow a compsot heap ot dry out .
How does the amount of oxygen effect the rate of decompostion ?
-Decomposer carry out aerobc respiration .
-This requires a good supply of oxygen .
What gardeners do in terms of amount of oxygen in compost ?
-Man gardners use a gardening fork , to mix their compost regularly , allowing more oxygen to pass into the center .
-Mixing the compsot also breaks up larger clumps , it increases the surface area for decompsoers to acton .
What do decomposers do if there is no oxygen ?
-Decomposers carry out anaerobbic decay .
-Anerobic decay produces a mixture of agses including methane - scientits call htis biogas .
What is biogas used for ?
-Small scale can be used by generators , providing fuel fo homs .
-Often using plant material like food waste or animal maure .
What are we investigating in this RQP ?
-We are investigting the effect of temeprture on the rate of decay on fresh milk by mesurin pH change .
What is the decay process of milk ?
Milk;
-If milk is left at room temperature , its goes sour , after a couple of days .
-As bavteira in the milk start the decy process .
-These bacteria use enzymes to produce acidic olecules , and that is why sour milk tatses acidic .
What is the problem with this RQP ?
-Decay is a very slow process , so it is hard to observe that in a lesson .
SOLUTIOn - is to model decay using the enzyme lipase .
(so we ren’t strirtly looking at decay , but apporximately , what is close to decay )
Stage one of decay rqp
-Label a tube ‘lipase’
-Use a pipette to place 5cm3 of lipase solution in the test tue .
Stage two of decay rqp
-Label another test tube ‘mlk’
-Add five drops of indicator cresol red .
Stage three of decay rqp
-Add 5 cm3 of milk and 7cm3 of sodium carbonate solution to the milk test tube .
-At this point , the solution should be pirpel - as sodium carbonate solution is alkaline and cresol red is purple in alkaline conditons .
Stage four of decay rqp
Place thermometer into the test tube containing the milk .
Stage five of decay rqp
Place both test tubes into beaker of water t our first chosen temperature .
(e.g 20 degrees - at room teperature ).
-At this point , we need to wait until the temperatures of our solution is the same as the water in the beaker .
Stage six of decay rqp
-NOw we use a pipette to transfer 1cm3 of lipase solutoin into the test tube containing milk and we stir the solution .
-At the same time we start a timer .
Stage seven of decay rqp
-At this point , the enzme lipase , will stat to breakdown the fat molecules in the milk .
-This releases fatt acids , causig the milk solution to become acidic .
Stage eight of decay rqp
In acidic conditions , cresol red changes to yellow .
-So once the solution turns yellow , we stop timing and record the results .
Stage nine of decay rqp
Repeat the experiment at a range of different temperatures .
What is the independant variable ?
Temperature .
What is the dependant variable?
Time taken for the milk solution to turn yellow .
WHat is the control variable ?
-The volumes of the different solutions .
-Need to make sure the volumes of lipase milk , sodium carbonate solution and cresol red do not change .
Why do we need to use a clean test tube for the milk solution in each experiment ?
-Any traces of lipase will trigger the reaction before we are ready .
What do we do with stopping the timer ?
-As we are looking for a change in colour , it can be difficult to decide when to stop thetimer .
-To reduce the effect of this , SHARE DATA , with other groups and calculate the mean .
Look at the graah , what does star one show ?
-At low temperautres , the reaction is slow .
-*As enzymes work slowly , at lower temperatures .
Look at the graph , what does star two show ?
At certain temperatures , the reaction is taking place at its fastestt rate , scientists callt his hte optimum temperature .
Look at the graph , what does star three show ?
In conditions that are warmeer than the optimum temperature , the reaction slows down , may even stop completely .
-As the enzyme denatures at higher temperature .
The RQP linking with decomposers .
-Dcomposers work faster in warm conditions but NOT IN hot conditons .
-This is becasue enzymes DENATURE , when the temperature is to high .
