B7 Core Questions
Topic 7 Ecology – Core Questions
1
What is an ecosystem?
An ecosystem is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
2
What is a habitat?
The place where an organism lives.
3
What is a population (in ecology)?
The total number of individuals of the same species.
4
What is a community (in ecology)?
A group of organisms of different species that share a geographical area.
5
State four factors plants compete with each other for.
Space, light, mineral ions, water
6
State three factors animals compete with each other for.
Food, mates, territory
7
What is interdependence?
Each species within a community depend on others for food, shelter, pollination, seed dispersal, etc. If one species is removed, this will affect the whole community.
8
What is a stable community?
A community where all the species and environmental factors are in balance so that population sizes remain fairly constant.
9
What is an abiotic factor?
A non-living variable which can affect a community.
10
State 3 of the 7 possible abiotic factors which may affect a community.
Light intensity, temperature, moisture levels, soil pH and mineral content, wind intensity (and direction), carbon dioxide concentration, oxygen concentration
11
What is a biotic factor?
A living variable which may affect a community.
12
State all 4 possible biotic factors which may affect a community.
Availability of food, new predators, new pathogens, being outcompeted
13
Organisms have adaptations to enable them to survive in their usual conditions. What 3 categories do these adaptations fall under?
Structural, behavioural, functional (cellular reactions)
14
What is an extremophile?
An organism that lives in an extreme environment, such as at high temperature, pressure or salt concentration.
15
Give an example of an extremophile.
Bacteria living in deep sea vents.
16
What is a producer?
A photosynthetic organisms that produces biomass.
17
What do all food chains begin with?
Producers
18
Give two examples of a producer.
Green plants and algae.
19
What does a producer make? How?
Glucose, through an endothermic chemical reaction known as photosynthesis.
20
Name 2 methods used by ecologists to determine the distribution and abundance of species in an ecosystem.
Random and systematic sampling.
21
Name 3 types of consumers and what they eat.
1. Primary consumers eat producers.
2. Secondary consumers eat primary consumers
3. Tertiary consumers eat secondary consumers
22
What is a predator?
A consumer that kills and eats other animals.
23
What are prey?
An animal that is killed and eaten by predator.
24
Why are all materials in the living world recycled?
To provide the building blocks for future organisms.
25
What uses carbon dioxide in the atmosphere?
Plants during photosynthesis.
26
State three processes which return carbon from organisms to atmospheric carbon dioxide.
1. Respiration – releases carbon dioxide.
2. Release (carbon containing) waste – microorganisms decompose this and respire – releases carbon dioxide.
3. Death – microorganisms decompose the body and respire – release carbon dioxide.
27
Where does the fresh water for animals and plants on land come from?
Continuous evaporation of water from oceans and precipitation over land.
28
State 3 factors which may affect the rate of decay of biological material.
1. Temperature
2. Water
3. Oxygen availability
29
What is compost used for by gardeners and farmers?
Used as a natural fertiliser for growing plants and crops.
30
What is a biogas generator and how does it work?
A generator used to anaerobically decay biological material which produces methane gas as a fuel.
31
Name 3 environmental changes that affect the distribution of species in an ecosystem.
Temperature, availabilty of water, composition of atmospheric gases
32
State three causes of environmental change.
Seasons, geographic location, human interaction
33
How do humans reduce the amount of land available for other animals and plants?
By building, quarrying, farming and dumping waste
34
Why are peat bogs being destroyed?
To produce garden compost.
35
What effect does destruction of peat bogs have on an area?
Reduces biodiversity.
36
What happens as a result of decay or burning of peat?
Release of carbon dioxide into the atmosphere.
37
What is biodiversity?
The variety of all the different species of organisms on earth, or within an ecosystem.
38
Why does having great biodiversity ensure stability in an ecosystem?
Because species have reduced dependence of one another for food, shelter and maintenance of the physical environment.
39
What is human activity reducing, which may be an issue for the future of the human species on Earth?
Biodiversity.
40
What is happening to the levels of resources we are using and the waste we are producing as human population rapidly grows?
Increasing (dangerously).
41
What is the increased release of waste and chemical materials causing?
(More) pollution.
42
How is water polluted?
Sewage, fertilisers or toxic chemicals.
43
How is air polluted?
Smoke and acidic gases.
44
How is land polluted?
Landfill and toxic chemicals.
45
Why does pollution reduce biodiversity?
It kills plant and animals.
46
Give three causes of deforestation.
1. Provide land for cattle or rice fields
2. Grow crops for biofuels
3. To clear space for building
47
Which 2 gases are increasing in the atmosphere and contributing to global warming?
1. Carbon dioxide
2. Methane
48
What are the five main biological consequences of global warming?
1. Increased spread of pathogens
2. Affecting migration patterns of animals
3. Melting of polar ice caps, causing flooding
4. Reduced habitats in polar regions
5. Reduced biodiversity
49
State three positive human interactions in an ecosystem.
1. Breeding programmes for endangered species
2. Protection and regeneration of rare habitats
3. Reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crop
4. Reduction of deforestation and carbon dioxide emissions by some governments
5. Recycling resources rather than dumping waste in landfill
50
State two negative human interactions in an ecosystem.
1. Clearing of land for agriculture, buildings and/or transport
2. Hunting of rare species
3. Mining from the land
51
What is a trophic level?
The position a species occupies in a food chain.
52
Name two organisms found in trophic level 1 (the lowest level).
Plants and algae.
53
What is the group name for organisms which are found in in trophic level 1?
Producers.
54
Name the group of organisms found in trophic level 2.
Herbivores or primary consumers
55
Name the group of organisms found in trophic level 3.
Carnivores that eat herbivores or secondary consumers.
56
What is the group name for carnivores with no predators?
Apex predators.
57
Which group of organisms break down dead plant and animal matter?
Decomposers (microorganisms).
58
How do they break down the plant & animal matter?
By secreting enzymes into the environment.
59
What do pyramids of biomass represent?
The relative amount of biomass in each level of a food chain.
60
In a pyramid of biomass, where would trophic level 1 be placed?
At the bottom.
61
Approximately how much light energy that falls on Earth is absorbed by plants and algae?
0.01
62
Approximately how much energy is transferred between a trophic level and the level above it?
0.1
63
State two reasons for the loss of biomass through a food web.
1. Not all the ingested material is absorbed, some is egested as faeces
2. Some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine
64
In a hypothetical food chain, the producers contain 500kJ of biomass. The primary consumers contain 435kJ of biomass. What is the percentage of energy transferred from producers to primary consumers?
(500 – 435) / 500 *100 = 13%
65
In the same food chain, the secondary consumers contain 326.25kJ of biomass. What fraction of the biomass was lost between the two levels?
435 – 326.25 = 108.75
108.75/435 = 0.25 = 1/4
66
What is "food security"?
Ensuring an entire population can be fed.
67
State six biological factors which threaten food security.
1. The increasing birth rate has threatened food security in some countries
2. Changing diets in developed countries means scarce food resources are transported around the world (e.g. quinoa from Chile)
3. New pests and pathogens that affect farming
4. Environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail
5. The cost of agricultural inputs (e.g. fertiliser)
6. Conflicts that have arisen in some parts of the world which affect the availability of water or food
68
How can the efficiency of food production from animals be improved?
69
State three ways the energy loss from animals can be reduced.
1. Limiting the movement of animals
2. Control the temperature of their environment
3. Feed animals a high-protein diet
70
Generally, what is happening to ocean fish stocks?
Stocks are declining.
71
What level of population must be maintained in fish to avoid extinction?
A large enough population to enable breeding.
72
How does controlling the net size used in fishing help sustainability?
Bigger holes in the net mean only large, adult fish are caught and smaller, younger fish are left to grow and reproduce.
73
How do fish quotas used in fishing help sustainability?
Prevents over-fishing of a species by fisherpeople from different countries.
74
What does the fungus Fusarium produce?
Mycoprotein (Quorn and other similar brands).
75
What is required to grow Fusarium?
Glucose syrup, oxygen.
76
What genetic characteristics could be used in developing GM crops?
Herbicide or pesticide resistance; increased growth or production; added nutritional value (e.g. golden rice, which contains high concentrations of Vitamin A).