B17 - Organisation of an ecosystem Flashcards
(42 cards)
1
Q
What do food chains show?
A
- Feeding relationships showing what organisms eat or are eaten by others and through this the levels of organisation in an ecosystem
- Add together to make food webs for a habitat
2
Q
What are producers?
A
- Photosynthetic organisms that are the producers of biomass
- At start of food chain
- e.g green plant or alga
3
Q
Structure of food chains?
A
Producer –> primary consumer –> secondary consumer –> predator
4
Q
What are primary consumers?
A
- Organisms that eat producers
5
Q
What are secondary consumers?
A
- Organisms that eat primary consumers
6
Q
What are predators and prey? What is their relationship in a stable community?
A
- Animals that hunt and kill others
- Those that are hunted and killed
- Numbers of predators and prey rise and fall in cycles
7
Q
What is the top animal in the feeding relationship called?
A
- Apex predator
8
Q
What are decomposers?
A
- Bacteria and fungi
- Break down dead organisms in a process called decomposition or rotting
- Release enzymes onto the dead matter and after consume the broken down substances
- Form a vital role in the recycling of matter
- Organisms die and decompose, plants absorb the broken down nutrients through their roots
9
Q
RP9 - Measure the population size of a common species in a habitat using random sampling(5)
A
- Place 5 quadrats randomly in an area in which conditions of a particular factor are similar(e.g high light intensity)
- Count number of organisms growing within that quadrat
- Identify outliers and calculate an average
- Repeat by placing 5 quadrats in contrasting conditions(e.g low light intensity)
- Compare data from different environment
10
Q
RP9 - Measure the population size of a common species in a habitat using continuous sampling(5)
A
- Lay down a tape measure the length of the area being investigated
- Put quadrat at 0cm mark and count how many of that organism are within the transect
- Record abiotic conditions
- Place a quadrat every 5m and count number of organisms within the quadrat. Record abiotic factors
- Repeat these steps with 4 more transects
11
Q
RP9 - Why should quadrats be placed randomly?
A
- To avoid bias
12
Q
RP9 - How could you position a quadrat randomly?
A
Throw over shoulder or with eyes closed or use a random number generator to create coordinates
13
Q
RP9 - When investigating distribution using quadrats how could you ensure results are valid?
A
- Repeat using more quadrats
14
Q
RP9 - When using a transect how could you ensure results are valid?
A
Repeat using a transect line in a different position
15
Q
RP9 - How could you estimate % cover using a quadrat?
A
- Count number of squares within quadrat more than 50% covered
- Divide by total number of squares in grid
- Multiply by 100
16
Q
RP9 - How could you estimate the number of organisms in a field?
A
- Find area of field and number of organisms in 1m2
- Multiply these numbers together
17
Q
RP9 - What is a transect?
A
- A line across a habitat
18
Q
RP9 - When would you use a transect?
A
- To investigate a gradual change in a habitat
19
Q
Why is it important to eestimate the number of organisms in a population?
A
- Better understand relationships in a community
- Monitoring impact of conservation projects aiming to conserve endangered species or habitats
20
Q
How is an estimate drawn?
A
- Sampling: number of organisms counted within a sample site, then multiplied to estimate total number
- Done through pitfall traps = small traps dug into the ground, often with food inside to attract small mammals
- Done through large nets to sweep through grasses or leaves of trees - sweep netting
21
Q
What are samples used for?
A
- See if number of species or percentage cover changes within an area
- Often as a result of a change in an abiotic factor
22
Q
Why is it important that materials are cycled?
A
- Provide building blocks for future organisms
23
Q
Which processes cycle carbon?
A
- Photosynthesis
- Respiration
- Combustion
24
Q
Word equation for photosynthesis?
A
Carbon dioxide + water –> glucose + oxygen
25
Word equation for respiration?
Glucose + Oxoygen ---> Carbon Dioxide + Water
26
Word equation for combustion?
Fuel + Oxygen --> Carbon Dioxide + Water
27
How do decomposers contribute to the carbon cycle?
- Help dead organisms break down and rot
- Help recycle minerals and nutrients to the environment - used by others
- Dead matter decomposed, decomposers also respire and release CO2
28
What are the stages of the carbon cycle?
1. Carbon enters atmosphere as CO2 from respiration and combustion
2. CO2 absorbed by producers to make carbohydrates in photosynthesis
3. Animals feed on plants, passing carbon compounds. Most carbon consumed is exhaled as CO2 during respiration
4. When they die, they are eaten by decomposers and carbon in their bodies is returned to the atmosphere as CO2, if it is blocked the material could be available as a fossil fuel for combustion
29
What happens during the water cycle?
- Provides fresh water for plants and animals on land before draining into the sea
- The water is continously evaporated and precipitated
30
What are the processes of the water cycle?
- Evaporation=water turns from liquid to gas, energy from sun evaporates water from all places
- Condensation=water cools and converts from gas to liquid, often forming clouds
- Tranport=water within clouds blown many miles by strong winds and transported to other areas
- Precipitation=rain, snow, hail and sleet fall
- Surface runoff=if large volume falls or ground is already wet some water can run along surface
- Infiltration=water fallen as precipitation absorbed into the ground, stored within underground rocks called aquifers
- Transpiration=plants need to maintain a constant stream of water to their leaves for transport and support, allow some water to evaporate as water vapour from their leaves
31
How does tempearture affect the rate of decay?
- Increased temperature increases rate of decay
- Decay stops if temperature is too hot as enzymes denature
32
How does water affect the rate of decay?
- Damp conditions increase rate of decay
33
How does availability of oxygen affect the rate of decay?
- Increased availability increases rate of decay
34
What is compost?
- A natural fertiliser used by gardeners used to help grow garden plants or crops
- Produced when gardeners and farmers try to provide optimum conditions for rapid decay of waste biological material
35
What does anaerobic decay produce?
- Methan gas
- Biogas generators used to produce methane gas as a fuel
36
RP10 - investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change(9)
1. Add 5cm3 of lipase to test tube
2. Add drops of creosol red to another test tube
3. Add 5cm3 of milk to same test tube
4. Add 7cm3 of sodium hydroxide to same test tube
5. Add thermometer to test tube
6. Add both test tubes to water bath
7. Remove 1cm3 of lipase and add it to milk
8. Time how long it takes for colour to change yellow
9. Repeat at different temperatures
37
RP10 - How do calculate uncertainty?
Range in values divided by 2(excluding outliers)
38
RP10 - What are detritus feeders?
- Include maggots and worms
- Eat the dead organism and produce waste
39
RP10 - What is the impact of increased moisture on rate of decay?
- Mircoorganisms involved with decay grow faster in moist conditions
- Moisture makes it easier for them to digest their food and prevents them from drying oit
40
RP10 - Is oxygen required for decay to happen?
- Many microorganisms can respire aerobically and anaerobically
41
RP10 - What is the impact of higher oxygen levels on rate of decay?
- Decay will happen faster
- More aerobic respiration will take place meaning more energy will be transferred to the cells
42
What environmental changes affect the distribution of species in an ecosystem?
- Temperature
- Availablity of water
- Composition of atmospheric gases
- May be seasonal, geographic or caused by human interaction
