Topic 15 Triple Ecology & energy flow

Question 1

ecosystem

Answer 1

is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of the environment

Question 2

A stable community

Answer 2

is one where all the species and environmental factors are in balance so the population sizes remain fairly constant

Question 3

To survive and reproduce organisms require a:

Answer 3

supply of materials from their surroundings and from the other living organisms there.

Question 4

Within a community each species depends on:
If one species is removed:

Answer 4

other species for food, shelter, pollination, seed dispersal etc.
it can affect the whole community

Question 5

Plants in a community or habitat often compete for

Answer 5

light, space, water and mineral ions

Question 6

Animals compete for

Answer 6

food, mates and territory

Question 7

Abiotic (non-living) factors which can affect a community are:

Answer 7

Light intensity
Temperature
Moisture levels
Soil pH and mineral content
Wind intensity and direction
Carbon dioxide levels for plants
Oxygen levels for aquatic animals

Question 8

Biotic (living) factors which can affect a community are:

Answer 8

Availability of food
New predators arriving
New pathogens
One species outcompeting another so the numbers are no longer sufficient to breed eg. introduction of grey squirrels into Britain leading to native reds being outcompeted

Question 9

Organisms have adaptations that enable them to

These

Answer 9

in the conditions in which they normally live.

adaptations may be structural (shape or colour), behavioural or functional (physiological).

Question 10

Some organisms live in environments that are very extreme, such as high temperature, pressure or salt concentration e.g
These organisms are called

Answer 10

eg. Bacteria living in deep sea vents. extremophiles.

Question 11

usually a : which:

Feeding relationships within a community can be represented by food chains. All food chains begin with a producer

Answer 11

All food chains begin with a producer which synthesises molecules and produces biomass for life on Earth. This is usually a green plant or alga which makes glucose by photosynthesis

Question 12

Producers are eaten by

which in turn may be eaten by

Answer 12

primary consumers,

secondary consumers and then tertiary consumers

Question 13

Trophic levels can be represented by numbers:

Answer 13

Level 1: Plants and algae make their own food and are called producers
Level 2: Herbivores eat plants/algae and are called primary consumers
Level 3: Carnivores that eat herbivores are called secondary consumers
Level 4: Carnivores that eat other carnivores are called tertiary consumers. Apex predators are carnivores with no predators.

Question 14

Pyramids of biomass can be constructed to represent the relative amount of

Trophic level 1 is at the

Answer 14

biomass in each level of a food chain

bottom of the pyramid.

Question 15

Producers are mostly plants and algae which transfer about

Only approximately x% of the biomass from each trophic level is transferred to the level above it.

Answer 15

1% of the incident energy from light for photosynthesis

10%

Question 16

Losses of biomass are due to:

Answer 16

Not all the ingested material is absorbed, some is egested as faeces
Some absorbed material is lost as waste, such as carbon dioxide and water in respiration, and water and urea in urine

Question 17

Consumers that kill and eat other animals are
and those eaten are

In a stable community the number of predators and prey:

Answer 17

predators
prey

rise and fall in cycles.

Question 18

Transects and quadrats are used by ecologists to determine the

Answer 18

distribution and abundance of species in an ecosystem

Question 19

Decomposers break down

Answer 19

dead plant and animal matter by secreting enzymes into the environment. Small soluble food molecules then diffuse into the microorganism.

Question 20

Gardeners and farmers try to provide optimum conditions for rapid decay of waste biological material. The compost produced is used as a

Answer 20

natural fertiliser for growing garden plants or crops

Question 21

Anaerobic decay produces ——- gas. ——— ———can be used to produce methane gas as a fuel

Answer 21

methane
Bio gas

Question 22

All materials in the living world are recycled to provide the

Answer 22

recycled to provide the building blocks for future organisms

Question 23

The carbon cycle returns

Answer 23

carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis

Question 24

The water cycle provides
water is continuously:

Answer 24

fresh water for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated

Question 25

Biodiversity is the

Answer 25

the variety of all the different species of organisms on earth, or within an ecosystem

Question 26

Rapid growth in the human population and an increase in the standard of living mean that increasingly Unless waste and chemical materials are properly handled,

Answer 26

more resources are used and more waste is produced. more pollution will be caused.

Question 27

Pollution can occur:

Answer 27

In water, from sewage, fertiliser or toxic chemicals In air, from smoke and acidic gases eg. sulfur dioxide On land, from landfill and from toxic chemicals eg. herbicides, pesticides

Question 28

Pollution kills which can

Answer 28

plants and animals which can reduce biodiversity

Question 29

Humans reduce the amount of land available for other animals and plants by

Answer 29

building, quarrying, farming and dumping waste

Question 30

The destruction of peat bogs, and other areas of peat to produce: reduces the area of this habitat and thus: The decay or burning of the peat releases:

Answer 30

garden compost the variety of different plant, animal and microorganism species that live there. carbon dioxide into the atmosphere

Question 31

Evaluate the environmental implications of deforestation Positives and Negatives

Answer 31

Positive Provide land for cattle and rice fields to increase food production Grow crops from which biofuels, based on ethanol, can be produced Negative Increased release of carbon dioxide into the atmosphere (because of burning and activities of microorganisms) Reduced rate of carbon dioxide removal from the atmosphere by photosynthesis Reduction in the biodiversity of plant and animal species

Question 32

Levels of carbon dioxide and methane in the atmosphere are increasing and Describe biological consequences of global warming

Answer 32

contribute to global warming Loss of habitat when low-lying areas are flooded by rising sea levels Changes in the distribution of species in areas where temperature or rainfall has changed Changes to the migration patterns of animals

Question 33

The scientific consensus about global warming and climate change is based on

Answer 33

systematic reviews of thousands of peer reviewed publications

Question 34

Environmental changes affect the distribution of species in an ecosystem. These changes include: Changes may be seasonal, geographic or caused by human interaction

Answer 34

Temperature Availability of water Composition of atmospheric gases

Question 35

A great biodiversity ensures the

Answer 35

stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment

Question 36

The future of the human species on Earth relies on us maintaining a: Many human activities are reducing biodiversity and only recently have measures been taken to try to stop this reduction

Answer 36

good level of biodiversity.

Question 37

Scientists and concerned citizens have put in place programmes to reduce the negative effects of humans on ecosystems and biodiversity:

Answer 37

Breeding programmes for endangered species Protection and regeneration of rare habitats eg. coral reefs, mangroves, heathland Reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crop Reduction of deforestation and carbon dioxide emissions by some governments Recycling resources rather than dumping waste in landfill

Question 38

Food security means having

Answer 38

enough food to feed a population

Question 39

Biological factors which are threatening food security include: Sustainable methods must be found to feed all people on Earth

Answer 39

The increasing birth rate in some countries Changing diets in developed countries means scarce food resources are transported around the world New pests and pathogens that affect farming Environmental changes that affect food production, such as widespread famine occuring in some countries if rains fail The cost of agricultural inputs Conflicts that have arisen in some parts of the world which affect the availability of water or food

Question 40

The efficiency of food production can be improved by

Answer 40

restricting energy transfer from food animals to the environment. This can be done by limiting their movement and by controlling the temperature of their surroundings. Some animals are fed high protein foods to increase growth.

Question 41

Fish stocks in the oceans are It is important to maintain fish stocks at a level where: or certain species may: ways to do this:

Answer 41

declining. breeding continues disappear altogether in some areas. Control of net size and the introduction of fishing quotas play important roles in conservation of fish stocks at a sustainable level

Question 42

Explain possible biotechnical and agricultural solutions to meet the demands of the growing human population

Answer 42

Modern biotechnology techniques enable large quantities of microorganisms to be cultured for food, using industrially controlled vats The fungus Fusarium is useful for producing mycoprotein, a protein-rich food suitable for vegetarians. The fungus is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified A genetically modified bacterium produces human insulin. When harvested and purified this is used to treat people with diabetes GM crops could provide more food or food with an improved nutritional value such as golden rice

Question 43

there is less : and less: every time you move up a stage in a food chain: There are usually fewer--------- every time you move up

Answer 43

energy and biomass organisms

Question 44

Using quadrats to estimate the population size of plants in a uniform environment

Answer 44

An area of 100 m2 will have been marked out for you using two 10 m tapes. Within this area is a population of daisies. Place a 0.25 m2 quadrat at 20 positions within the marked-out area, using random coordinates to place quadrats randomly. Count the number of daisies within each quadrat and record in the table below. Calculate the mean number of daisies per quadrat. Use the formula to estimate the total number of daisies in the 100 m2 area. Estimated population size = total area × mean number of daisies counted area of quadrat

Question 45

Method- RP 10 Decay

Answer 45

Aim To investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change. Background Decomposers release extracellular enzymes to digest large molecules. The smaller products of digestion are then absorbed by the decomposers. In this practical, the large fat molecules in milk will be digested into smaller molecules. Think: What are the small products of fat digestion? Which type of enzyme would be released by decomposers to digest fat? An indicator called Cresol red is purple in alkaline solutions and yellow in acidic solutions. The time taken for Cresol red to change colour will be used to measure how long the milk takes to decay. Method You have been provided with a boiling tube containing 1cm3 of lipase. Take an empty boiling tube and label it “milk”, then add: 5 cm3 milk 7 cm3 sodium carbonate solution 5 drops of Cresol red The solution should now be purple. Put both tubes in a water bath as indicated by your teacher. Place a thermometer into the “milk” tube and wait until the contents reach the same temperature as the water bath. Once the required temperature is reached, pour the contents of the “milk” tube into the “lipase” tube and briefly shake to mix. Immediately start the stopwatch. Gently shake the contents of the “lipase”, holding the tube away from you, until the solution turns yellow. Record the time taken for the colour to change to yellow, in seconds. If no colour change occurs after 10 minutes, stop timing and record “ > 600”. Enter your data into the class spreadsheet. Repeat steps 1-8 using a different temperature as indicated by your teacher.

Question 46

Explain how temperature, water and availability of oxygen affect the rate of decay of biological material

Answer 46

temp: warmer temps make things decompose quicker because they increase the rate that the enzymes decompose at. If it's too hot though decomposition slows down or stops because enzymes are destroyed. Really cold temps slow rate of decomposition too water availability: decay takes place faster in moist environments because organisms involved in decay need water to carry out biological processes oxygen availability: many organisms need oxygen to respire

Question 47

Explain the role of microorganisms in cycling materials through an ecosystem by returning carbon to the atmosphere as carbon dioxide and mineral ions to the soil

Answer 47

mineral ions are returned to the soil when organisms die and decay. materials decay by microogranisms putting stuff that plants need to grow back in the soil this is a constant cycle co2 removed by plants during photsynthesis carbon used to help make glucose when plant eaten by animals carbon becomes part of fats and proteins in their bodies carbon then moves thru the foo chain.when animals and plants die microorganisms feed on them and respire co2 retunrd to atmos processes restarts