Ecology

Question 1

What are the two ways of sampling? (SO E Bi)

Answer 1

• random sampling
• sampling along a transect

Question 2

What is random sampling used for? (SO E Bi)

Answer 2

to compare the numbers of organisms in different areas.

Question 3

How do you do random sampling with a quadrat and what is the technique used for? (SO E Bi)

Answer 3

place it randomly on the ground and count the number of organisms inside the quadrat. Do this a large number of times to make it more likey that we get valid results. This techniwue is used to sample plants or slow moving animals

Question 4

What is a quadrat and how do you use it? (SO E Bi)

Answer 4

a wooden or plastic square used in random sampling.
place it on the ground and count the number of organisms inside the quadrat.

Question 5

How do we use random sampling to estimate the total population size of a species in an area? (SO E Bi)

Answer 5

Use this equation:

total poulation size =( total area / area sampled ) x number of organisms of that species counted in sample

Question 6

Why is it important that we place a quadrat a large number of times? (SO E Bi)

Answer 6

to make it more likely that we get valid results. If we place it only once that it might not give us a sample which accuratly represents the whole area.

Question 7

When do we use sampling along a transect? (SO E Bi)

Answer 7

when we want to ivestigate wether the numbers of species change as we move across a habitat

Question 8

What is a transect and where do we place it when doing sampling? (SO E Bi)

Answer 8

a line such as a tape measure or a piece of rope. We place the transect so it runs across the habitat that we are investigating

Question 9

How do you do transect sampling? (SO E Bi)

Answer 9

1. place the transect across the habitat
2. place qudrats at intervals on the transect
3. count the number of organisms in these transects
4. repeat this a number of times so that we get valid results - move the transect across

Question 10

What size of quadrat do we use for estimating the total population of daisies? (RP9 E Bi)

Answer 10

0.5m x 0.5m

Question 11

What is the method for the required practical of estimating the total polulation of diasies? (RP9 E Bi)

Answer 11

Use random sampling
1. Place two tapemeasures at right angles (20m in length)
2. Have two bags which each have numbers 1 to 20 in
3. 1 takes a number from the bag e.g 8. They then move to the 8m point on one of the tape measures
4. 2 takes a number from the bag and moves to that point on the other tape measure. e.g 12
5. 3 takes a quadrat (0.5m x 0.5m) and places it on the ground at the 8m by 12m point
6. record the number of daisies in the first quadrat
7. place the numebrs back into the bag
8. rpeat this process nine more times for a total of 10 samples
9. work out the estimated total population size.

Question 12

What should you do in the sampling daisies rp when you think that there are large amount that have too many or too little daisies and don’t represent the whole field? (RP9 E Bi)

Answer 12

increase the number of samples that you do so that you can cover a greater percentage of the area

Question 13

How do you find out how light intensisty affects the number of diasies in an area and what do we expect to come from this experiment? (RP9 E Bi)

Answer 13

transect sampling.
One end of the tape measure should be under a shady part and then it should stretch into the sunny parts
1. record the number of diasies and the light intesisty (ap or light meter) at the shadiest end of the tape measure
2. move the quadrat 1m down the tape measure and repeat the measurements
3. continue all the way down the tape measure
We are likely to find that there is a larger amount of dasisies as we move away from the tree. Because there will be a lower light intensity and plants need light to photosynthesise. Also the tree will absorb a lot of the water and minerals from the soil so light intensity might not be the only abiotic factor affecting the number of daisies

Question 14

What does every food chain start with? (FCPPC E Bi)

Answer 14

A producer. which is usually a green plant.

Question 15

Why are producers extremely important in food chains? (FCPPC E Bi)

Answer 15

they synthesise complex molecules which are passed through the food chain. Green plants make the molecule glucose by photosynthesis by using energy from the sun
they are the sources of all biomass in a community

Question 16

What are molecules such as glucose called? (FCPPC E Bi)

Answer 16

biomass

Question 17

What are the organisms that eat the producers called? (FCPPC E Bi)

Answer 17

primary consumer

Question 18

What is a secondary consumer? (FCPPC E Bi)

Answer 18

an animal that eats a primary consumer

Question 19

What is a tertiary consumer? (FCPPC E Bi)

Answer 19

An animal that eats a secondary consumer

Question 20

What are consumers that kill and eat other animals called? (FCPPC E Bi)

Answer 20

predators

Question 21

What is an animal that is being eaten called? (FCPPC E Bi)

Answer 21

prey

Question 22

What do the numbers of predators and prey do? (FCPPC E Bi)

Answer 22

they fluctuate in cycles. (rise and fall). But this is only in a stable community - if a drought happened or a new predator arrived then the predator-prey cycles would start to change

Question 23

What is a stable community? (FCPPC E Bi)

Answer 23

when biotic and abiotic factors are in balance.

Question 24

What is biomass? (PB E Bi)

Answer 24

the mass of all organisms at a certain tophic level.
Biomass is the living tissure of an organism including proteins lipids and carbohydrates.

Question 25

Why would a scientist dry out all of the organisms that they want to measure the biomass for? (PB E Bi)

Answer 25

because dry biomass is a lot more useful than wet biomass. This is because the moisture content of organisms can vary widely and prodcuce innaccurate results

Question 26

What percentage of sunlight is absorbed by producers and used for photosynthesis? (PB E Bi)

Answer 26

1%

Question 27

What does the amount of biomass do as you move up the trophic levels? (PB E Bi)

Answer 27

It decreases

Question 28

Why does the amount of biomass decrease as you move up the trophic levels? (PB E Bi)

Answer 28

1. not all of the material that the bird ingests is absorbed - some is egested as faeces 2. some of the biomass that is absorbed is converted into waste products of metabolism and is released - urea in humans 3. a large amount of biomass is used by the bird for respiration to release energy (used in movement and some to maintain a constant body temerpature) and create waste compunds (water and carbon dioxide)

Question 29

What does aerobic respiration release? (PB E Bi)

Answer 29

energy, carbon dioxide and water

Question 30

Around what percantage of biomass at what tophic level is passes onto the next one? (PB E Bi)

Answer 30

10%

Question 31

What does the loss of biomass as you move up the tophic levels mean? (PB E Bi)

Answer 31

in most food chains, the number of organisms at each trophic level tends to decrease and there is a very small number of food chains with a large number of trophic levels

Question 32

How do you calculate the efficiency of biomass transfer? (PB E Bi)

Answer 32

efficiency = gain in biomass / total biomass intake

Question 33

What does the carbon cycle start with and where? (CC E Bi)

Answer 33

Starts with carbon dioxide in the atmousphere

Question 34

What is the only way that carbon can enter the carbon cycle? (CC E Bi)

Answer 34

through photosynthesis

Question 35

How does carbon get back into the atmousphere in the carbon cycle? (CC E Bi)

Answer 35

aerobic respiration

Question 36

What are the two main processes in the carbon cycle? (CC E Bi)

Answer 36

photosynthesis - brings carbon into the cycle aerobic respiration - returns carbon to the atmosphere

Question 37

Describe the carbon cycle: (CC E Bi)

Answer 37

**Atmosphere:** carbon dioxide in the atmosphere **plants and algae:** - take the carbon dioxide from the atmosphere by photosynthesis - the carbon is used for making carbohydrates, fats and proteins which makes up their cells - they respire so some carbon is released back into the atmosphere as carbon dioxide **animals:** - eat the plants and the algae - some eat the animals who ate the plants and algae - the carbon becomes their carbohydrates, fats and proteins for their cells - they respire so some carbon is released back into the atmosphere as carbon dioxide - animals produce waste products such as faeces and they all die eventually **decomposing microorganisms:** - bacteria and fungi - the waste products and dead remains are broken down - they respire so the carbon from the waste products and the dead remains is returned to the atmosphere as carbon dioxide - release imernal ions to the soil **fossil fuels:** - under certain conditions, decomposers cannot function effectively so the carbon in the dead remains will slowly be converted to fossil fuels - a large amount of carbon has been trapped underground as fossil fuels over millions of years - humans have been buring fossil fuels. this combustion is releaseing a large amount of carbon dioxide back in the atmosphere

Question 39

Whhy do farmers use compost as a natural fertiliser? (D E Bi)

Answer 39

compost is very rich in the minerals that plants need to grow

Question 40

What are the names of the optimal conditions for decompositon (conditions that make decomposition take place most rapidly)? (D E Bi)

Answer 40

1. temperature 2. amount of water 3. amount of oxygen

Question 41

At which temperatures does decomposition take place faster and why? (D E Bi)

Answer 41

warmer because the decomposers use enzymes to break down the plant materials and these enxymes work faster in warm conditions. BUT NOT TOO WARM coz enzymes can denature

Question 42

Why do compost heaps tend to be quite warm anyway? (D E Bi)

Answer 42

because decomposers release energy when they carry out aerobic respiration

Question 43

Why is it important that compost does not get too hot? (D E Bi)

Answer 43

the enzymes in the decomposers can denature and the decomposers can die.

Question 44

What amount of water do microorganisms require to work fastest? (D E Bi)

Answer 44

if the compost is moist it will have the fastest miccroorganisms because many of the chemical reactions in decay require water so it is important that the compost heap does not dry out

Question 45

Why does compost need to be moist? (D E Bi)

Answer 45

lots of the chemical reactions require water

Question 46

Why do decomposers need a good amount of oxygen? (D E Bi)

Answer 46

becasue the decomposer microorganisms aerobically respire and it requiers a good amount of oxygen. (compost bin with enough oxgen to enter could have holes in the sides.

Question 47

What are the ways of allowing oxygen into compost heaps/bins?

Answer 47

1. have a compost bin with holes in it so that oxygen can get in 2. gardening fork to mix the compost regularly which allows more oxygen to pass into the centre. It also breaks up large clumps and also increases the surface area for decomposers to act on.

Question 48

What happens if there is no oxygen in the compost? (D E Bi)

Answer 48

the decomposing microorganisms carry out anaerobic decay which produces a mixture of gases including methane <- biogas

Question 49

What do biogas generatures use?(D E Bi)

Answer 49

plant materials such as food waste or animal manure

Question 50

When do decomposers produce biogas? (D E Bi)

Answer 50

Under anaerobic conditions

Question 52

How is methane released? (GW E Bi)

Answer 52

- by bacteria in paddy fields (growing rice) - cows when they trump

Question 53

What are both carbon dioxide and methane? (GW E Bi)

Answer 53

greenhouse gases - trap heat in the atmosphere which leads to global warming

Question 54

What is peer- review and what does it help do?

Answer 54

scientists checking eachothers work and helps to detect false claims and makes sure that research published in scientific journals is valid

Question 55

What are the consequencses of popular media (newspapers) not being subject to peer review? (GW E Bi)

Answer 55

reporting on global warming can sometimes be oversimplified inaccurate or biased

Question 56

What is one of the main consequences of global warming? (GW E Bi)

Answer 56

loss of habitats e.g loss of ice levels in the Arctic which will cause the population of arctic organisms such as polar bears to fall as their habitat is reduced

Question 57

What will happen to aniamls such as birds and insects as temperatures rise? (GW E Bi)

Answer 57

gradually extend their range nothwards towards cooler conditions (malaria can be brought up to the UK) also migration patterns could change

Question 59

How will temperatures increasing due to global warming affect plants? (GW E Bi)

Answer 59

spring plants are flowering earlier due to warmer conditions. We may be able to grow grapes in parts of the UK where we cannot today but in other parts of the world it may become too hot to grow the crops that are needed.