Topic 7-Ecology Flashcards
1
Q
What is an ecosystem?
A
The interaction between the living components and non-living components
2
Q
What are the levels of organisation in an ecosystem?
A
Individual, population, community, ecosystem
3
Q
What are some factors that plants may compete for?
A
- Light
- Space
- Water
- Mineral ions from soil
4
Q
What are some factors that animals may compete for?
A
- Food
- Mates
- Territory
5
Q
What is intraspecific competition?
A
Competition within a species
6
Q
What is interdependance?
A
Different species in an ecosystem depend on each other for various resources, if one species is removed, the whole community may be affected
7
Q
What is a stable community?
A
- Biotic and abiotic factors are in balance
- Population sizes remain constant
- When lost, it can be very hard to replace them
- Tropical rainforests, oak woodlands and coral reefs
8
Q
What is an abiotic factor?
A
A non-living factor
9
Q
State some abiotic factors that may affect an ecosystem
A
- Light intensity
- Temperature
- Moisture
- Soil pH and mineral content
- Wind intensity
- Carbon dioxide level
- Oxygen level
10
Q
Why might light intensity affect an ecosystem?
A
- Required for photosynthesis
- Rate of photosynthesis affects the rate at which the plant grows
- Plants can be food sources or shelter for many organisms
11
Q
Why might temperature affect an ecosystem?
A
Temperature affects the rate of photosynthesis
12
Q
Why might moisture levels affect an ecosystem?
A
Both plants and animals need water to survive
13
Q
Why might soil pH and mineral content affect an ecosystem?
A
Soil pH affects the rate of decay and therefore how fast mineral ions return to soil (which are then taken up by other plants)
Different species of plants of thrive in different concentration levels
Most plants require a high level of soil minerals to grow well
14
Q
Why might CO2 levels affect an ecosystem?
A
CO2 affects the rate of photosynthesis in plants
It also affects the distribution of organisms as some thrive in high CO2 environments
15
Q
Why might oxygen levels for aquatic animals affect an ecosystem?
A
- Levels in water vary greatly, unlike oxygen levels in air
- Most fish need a high concentration of oxygen to survive
16
Q
What is a biotic factor?
A
It is a living factor
17
Q
State biotic factors that may affect an ecosystem?
A
Food (more food means organisms can breed more successfully and therefore the population can increase in numbers)
New predators
New pathogens (when a new pathogen arises the population has no resistance to it so they can be wiped out quickly)
Competition (if one species is better adapted to the environment than another, then it will outcompete it until the numbers of the lesser adapted species are insufficient to breed)
18
Q
Define population
A
A species that occupy the same habitat
19
Q
Define habitat
A
The place in which an organism lives
20
Q
Define community
A
Populations of different species interacting
21
Q
Define biomass
A
The total mass of living material
22
Q
What are trophic levels
A
The stages in a food chain
23
Q
Describe a simple food chain
A
Producer-Primary consumer-Secondary consumer-Tertiary consumer
24
Q
What is a producer
A
An organism that makes its own food
25
What types of organisms are primary producers?
Photosynthetic organisms like green plants and algae that trap energy from the sun
Through photosynthesis, they make glucose
Glucose is used to make other biological molecules in the plant
26
What piece of apparatus is used to measure the abundance and distribution of organisms in an area?
A quadrat
27
How does wind intensity affect an ecosystem?
Plant seeds are more likely to germinate in locations with lower wind intensity, which may also attract animals that depend on the plant to live nearby
28
What do food chains show?
Food chains show the feeding relationships of different organisms and the flow of energy between the organisms
29
What do arrows in a food chain represent?
The direction of biomass transfer
30
What is a predator?
A consumer that kills and eats other animals
31
What is prey?
An animal that is killed and eaten by another animal
32
Describe the pattern of predators and prey in a stable community
The numbers of predators and prey rise and fall in cycles
33
Why are producers the first trophic level?
Producers provide all biomass for the food chain (production of glucose via photosynthesis)
The rest of the food chain involves the transfer of this biomass
34
What piece of apparatus is used to study the distribution of organisms across a gradient?
Belt transect
35
Describe a population cycle within a stable community between the predators and prey
If the population of prey increases, the population of predators will also increase
This will result in the number of prey decreasing after some time as more would be consumed by the increased number of predators
When there isn't enough prey to feed all the predators, the population of predators will decrease, which will allow the population of prey to increase again
36
Describe how materials cycle through the living and non-living components of an ecosystem
Organisms take in elements from their surroundings e.g soil, air
Elements converted to complex molecules which become biomass
Elements transferred along food chains
Elements returned to environment during excretion and decomposition of dead organisms
37
Give 3 molecules which are cycled through ecosystems
Oxygen, carbon dioxide and water
38
Describe how CO2 is removed from the air during the carbon cycle
CO2 is removed from the air in photosynthesis by green plants and algae- they use the carbon to make carbohydrates, proteins and fats. They are eaten and the carbon moves up the food chain
39
Describe how CO2 is returned to the air during the carbon cycle
CO2 is returned to the air when plants, algae and animals respire.
Decomposers (a group of microorganisms that break down dead organisms and waste) respire while they return mineral ions to the soil
CO2 is returned to the air when wood and fossil fuels are burnt (called combustion) as they contain carbon from photosynthesis
40
Describe the water cycle
The sun's energy causes water to evaporate from the sea and lakes, forming water vapour
Water vapour is also formed as a result of transpiration in plants
Water vapour rises and then condenses to form clouds
Water is returned to the land by precipitation (rain, snow or hail), and this returns to lakes via surface runoff to provide water for plants and animals
This then runs into seas and the cycle begins again
41
Why is the carbon cycle important?
Carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells
42
Why is the water cycle important?
Living organisms require water and the water cycle provides organisms on land with a continuous supply of water
43
How does temperature affect the rate of decomposition?
Chemical reactions generally work faster in warmer conditions, but if it is too hot the enzymes can denature and stop decomposition
44
How does water affect decomposition?
Microorganisms grow faster in conditions with water as it is needed for respiration. Water also makes food easier to digest
45
How does availability of oxygen affect the rate of decomposition?
Most decomposers respire aerobically
46
Why are microorganisms important for the cycling of materials through an ecosystem?
Microorganisms (bacteria and fungi) return carbon to the environment by releasing carbon dioxide through respiration while they decompose dead matter.
The decomposition of dead matter in soils returns mineral ions to the environment for other organisms to use eg plant use mineral ions for growth
47
What is meant by decompositon?
The breakdown of dead materials into simpler organic matter
48
How do decomposers break down dead matter?
Decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules
49
What are the two types of decomposition?
Aerobic decomposition (with oxygen)
Anaerobic decomposition (without oxygen)
50
What factors affect the rate of decomposition?
Oxygen availability
Temperature
Water content
51
Why is oxygen required for decomposition?
Most decomposers require oxygen for aerobic respiration
52
Why can decomposition still occur in the absence of oxygen?
Some decomposers respire anaerobically
However the rate of decomposition is slower as anaerobic respiration produces less energy
53
How does soil water content affect the rate of decomposition?
Decomposers require water to survive
In most conditions the rate of decomposition is high
In waterlogged soils there is little oxygen for respiration so the rate of decomposition decreases
54
Why does decomposition require water?
Water is required for the secretion of enzymes and absorption of dissolved molecules
55
How is the rate of change calculated when considering the decay of biological material?
Rate of change= change in value/change in time
Where value is a measurable variable associated with the decay of the material
56
What is compost?
The nutrient-rich product of the rapid decay of water biological material (dead plants and animal waste) in optimum conditions set by gardeners and farmers
57
How is compost used?
It is used as natural fertiliser to promote growth of crops or garden plants
58
Describe how biogas generators work
Biogas generators provide methane gas for fuel through anaerobic decomposition that occurs in animal waste
59
What are some of the conditions needed for biogas generators?
They require a constant temperature (30 degrees) so the microorganisms keep respiring
It cannot be stored as a liquid so it needs to be used immediately
60
How is methane gas produced?
Microorganisms decompose waste anaerobically to produce methane gas
This can be burnt as a fuel
61
The carbon in dead leaves is recycled through the carbon cycle
Explain how the carbon is recycled into the growth of new leaves
Microorganisms respire and release the carbon from the leaves as carbon dioxide
Plants take in the carbon dioxide released to use in photosynthesis to produce
Glucose produces in photosynthesis is used to make amino acids
These are required for the growth of new leaves
62
Why did the strawberry decay?
Stored at a higher temperature
More oxygen
More water/moisture
More microorganisms that cause decay
63
Give one way in which food production might be more efficient from battery chickens that from free-range chickens
Limits their movement which reduces energy transfer
64
Name two products other than methane that are products of anaerobic respiration
Ethanol
Carbon dioxide
Lactic acid
65
In the quadrat practical, how can you make an estimate more accurate?
Use bigger quadrats
Do repeats of the quadrats in different locations
More quadrats placed randomly
66
Why might a conclusion not be correct?
Didn't carry out repeats
Mass may have not been the same each time
Only tested a certain amount of variables
Temperature of surroundings may have been different each time
67
How do you use the quadrat with a tape measure to distribution along a distance?
Place 30m tape measure across field
Place quadrat next to tape
Count amount of item
Repeat at regular intervals
68
How can you improve a quadrat investigation so that a valid conclusion can be made?
Repeat quadrat countings at different locations
69
Why does turning over a compost heat make the waste decay more quickly?
Oxygen is added which aids aerobic respiration of microorganisms
70
Why do plants in a woodland grow well each year without material from compost heaps being added?
Dead leaves fall off of trees and minerals are released into the soil
71
Why might gardeners be against producing compost through anaerobic decay?
Methane is produced which is a greenhouse gas
72
Explain how carbon is recyled into the growth of new leaves
Carbon compounds in dead leaves are broken down by microorganisms.
These microorganisms respire aerobically and release the carbon from the leaves as carbon dioxide
Plants take in the carbon dioxide that has been released to use in photosynthesis to produce glucose
Glucose produced in photosynthesis is used to make amino acids and proteins which are required for the growth of new leaves
73
When fertiliser/minerals go into a river or stream, why does the concentration of oxygen decrease and how does it affect other plants and invertebrates?
fertiliser/ions/salts cause growth of algae/plants
(algae/plants) block light for photosynthesis
(low light) causes plants to die
microorganisms cause decay of organic matter /dead plants
(aerobic) respiration (by microorganisms) uses O2 and releases carbon dioxide
Since the microorganisms use up all the O2, invertebrates die due to lack of oxygen
This is known as eutrophication
74
Give one way in which food production may be more efficient from battery chickens than free-range chickens.
It limits the chickens movement which reduces energy transfer
75
Why would the volume of biogas produced be less at a higher temperature than 35 degrees celcius?
Enzymes would become denatures
Enzyme shape is vital for function
76
Food chains are usually not more than 5 organisms long
Why?
Not enough biomass/energy
77
How can micro-organisms help to recycle materials
Microorganisms decompose materials and this releases materials
78
Why do lighter birds require more energy per day per gram of body mass?
Bird has large SA:V ration
Heat is lost more quickly
