B4

Question 1

Describe how to use pitfall traps.

Answer 1

Question 2

Describe how to use quadrats.

Answer 2

Question 3

List 3 methods for capturing insects.

Answer 3

Insects can be captured using sweep nets, pooters and pitfall traps.

Question 4

Describe the capture–recapture technique.

Answer 4

• Animals are trapped, eg using pitfall traps.
• They are marked in a harmless way and then released.
• Traps are used again a few days later.
• The numbers of marked and unmarked animals caught in the traps are recorded.
• The population size is estimated using the following equation:

Question 5

Give definitions for the words abiotic and zonation.

Answer 5

Abiotic factors are non living factors such as pH levels, light and temperature. Zonation describes the distribution of species living in different bands or zones in a particular area.

Question 6

What does the kite diagram below show?

Answer 6

The diagram shows a count of some common tree-species recorded while walking inland from a lake-shore into a forest.

Question 7

Explain why plants grow faster in summer rather than in winter.

Answer 7

In the summer there is more sunlight to provide energy for photosynthesis. It is also warmer which will help the plant enzymes to catalyse chemical reactions.

le>

Question 8

Explain why plants carry out
respiration as well as
photosynthesis.

Answer 8

Plants respire all the time because their cells need energy to stay alive. Plants can only photosynthesise when they are in the light, they do this to make glucose which is used in respiration.

Question 9

Which pigment in chloroplasts absorb light energy?

Answer 9

Chlorophyll.

Question 10

How do materials for photosynthesis enter and leave the plant?

Answer 10

Water enters through the root and leaves via pores in the leaves called stomata. Carbon dioxide enters the leaves through the stomata and oxygen exits through the stomata too.

Question 11

Why do broad leaves allow large amounts of light to be absorbed.

Answer 11

Broad leaves have a large surface area to allow the absorbtion of large amounts of light.

Question 12

Describe the main features of a plant cell.

Answer 12

Question 13

What is the role of the cell wall in a plant?

Answer 13

The cell wall provides a plant with structural support.

Question 14

What is the role of a cell membrane?

Answer 14

The cell membrane allows the movement of substances in and out of the cell.

Question 15

Describe how water travels through the plant in the diagram below.

Answer 15

Water travels through the plant by transpiration. As water evaporates from the stomata in the leaves, more water is absorbed by the root hair cells and up through the xylem vessels.

Question 16

What does the data below tell your about transiration rates.

Answer 16

Water loss by transpiration in plants is faster in conditions with high air movement (fan) and high light intensity. There is less water loss in misty or humid conditions.

Question 17

Describe an experiment using a potometer to show how transpiration is affected by external conditions.

Answer 17

Look at the information below.

Question 18

Which minerals do fertilisers contain?

Answer 18

Nitrogen (N), posphate (P) and potassium (K).

Question 19

Describe how minerals are absorbed by plants.

Answer 19

Minerals which are dissolved in water in the soil are absorbed by the root hair cells by active transport. The process requires energy as the minerals are absorbed up a concentration gradient.

Question 20

What are the main factors that affect the rate of decay?

Answer 20

The factors that affect the rate of decay include: moisture, temperature and amount of available oxygen.

Question 21

Describe the role of the vascular bundles in plants.

Answer 21

Question 22

Describe an experiment to show
decay depends on decomposers
such as bacteria and fungi

Answer 22

Look at the information table below.

Question 23

What is detritous.

Answer 23

Detritous is dead and decaying matter.

Question 24

Describe the importance of saprophites in decay.

Answer 24

Bacteria and fungi are the main decomposers. Bacteria are single-celled microscopic organisms. Fungi are often larger organisms that include moulds and mushrooms. They both cause decay by releasing enzymes onto the dead animal or plant. These break down complex compounds into simple soluble ones that can be absorbed by decomposers. Organisms that feed on dead material in this way are called saprophytes.

Question 25

What are detritivores?

Answer 25

Detritivores, help speed up decay by feeding on detritus. This is dead and decaying material. They break it down into smaller pieces, so increasing the surface area for the bacteria and fungi. Detritivores include:
Earthworms that help break down dead leaves
Maggots that feed on animal tissue
Woodlice that break down wood

Question 26

Why do food preservation methods work?

Answer 26

Food preservation methods reduce the risk of decay allowing the food to last longer.

Question 27

Describe the methods used to preserve food.

Answer 27

Look at the information table below.

Question 28

Describe the use of hydroponics in intensive farming.

Answer 28

In hydroponics soil is replaced by a mineral solution pumped around the plant roots. Removing the soil means there’s no risk of soil organisms causing disease but the plants have to be supported.
It allows crops to be grown in regions where there’s no soil. Due to the costs involved, hydroponics is used only for high-value crops

Question 29

What is organic farming?

Answer 29

An alternative way to produce food by limiting the use of fertilisers, herbicides and pesticides, and replace these with more ‘natural’ methods.
Some believe this produces higher quality food, and that it doesn’t raise as many ethical concerns as there’s less environmental impact. Food produced organically tends to be more expensive as the yield is lower than intensively produced food.

Question 30

Describe organic farming techniques.

Answer 30

Question 31

Give a definition for diffusion. You can use the diagram below to help.

Answer 31

Diffusion occurs when particles move from a region where they are in high concentration to a region where they are in low concentration. This happens in gases and for particles dissolved in solutions. Particles diffuse down a concentration gradient until they are evenly spaced out.

Question 32

Give definition for the words lysis, crenation, turgid, plasmolysed and flaccid.

Answer 32

Lysis – bursting an animal cell by osmosis
Crenation – shrinking an animal cell by osmosis
Turgid – a plant cell fully inflated with water
Plasmolysed – a plant cell that has lost water causing the cell membrane to be pulled away from the inside of the cell wall
Flaccid – a plant cell that is limp through a reduction of pressure inside the cell

Question 33

Describe how to use a transect line

Answer 33

A transect is line across a habitat or part of a habitat. It can be as simple as a string or rope placed in a line on the ground. The number of organisms of each species can be observed and recorded at regular intervals along the transect.

Question 34

Describe the differences in biodiversity in natural and artificial ecosystems

Answer 34

Natural ecosytems will have a greater amount of biodiversity than artificial ecosyatems

Question 35

What is the word equation for photosynthesis.

Answer 35

Question 36

State the balanced symbol equation for photosynthesis

Answer 36

See the image below.

Question 37

Describe the discoveries of Greek scientists, Van Helmont, Priestley

Answer 37

Scientists in ancient Greece believed that plants gained mass only by taking in minerals from the soil. Van Helmont carried out an experiment to see if the idea from ancient Greece was correct; He thought that the extra plant material had come from the water alone. Joseph Priestley carried out an experiment that showed that plants produce oxygen. This gas is oxygen.

Question 38

Describe how the rate of photosynthesis can be increased

Answer 38

The rate of photosynthesis can be increased by increasing light intensity, carbon dioxide levels and temperature.

Question 39

Explain why plants carry out respiration at all times

Answer 39

Plants carryout respiration at all times because it provides the energy they need for cellular processes.

Question 40

Explain how different pigments absorb light from different parts of the spectrum

Answer 40

Chlorophyll is the main photosynthetic pigment. The image below shows the amount of light absorbed by different pigments. Having several chloroplast pigments means that plants can absorb light across a greater range of colour wavelengths.

Question 41

Explain how leaves are adapted for efficient photosynthesis

Answer 41

Question 42

Name and locate the parts of the cross section of a leaf.

Answer 42

Question 43

Explain what diffusion is, you can use the picture below to help.

Answer 43

Particles in liquids and gases tend to move from an area of high concentration to an area of low concentration , down a concentration gradient until they are evenly spread (reach equilibrium).

Question 44

Explain what osmosis is using the idea of a partially-permeable membrane.

Answer 44

The net movement of water through a partially permeable membrane from an area where it is highly concentrated to an area of low water concentration.

Question 45

Explain how plants are supported by turgor pressure in its cells.

Answer 45

Plant cells in a dilute solution take up water by osmosis.The pressure inside the cell increases, this is called turgor pressure. The cell becomes firm or turgid and is able to provide structural support for the plant.

Question 46

Describe the effects of uptake and loss of water from animal cells.

Answer 46

When an animal cell is placed in a concentrated solution, it will loose water by osmosis. The cell becomes crenated (it crinkles). When an animal cell is placed in a dilute solution it takes up water by osmosis, swells and may burst. This is called lysis.

Question 47

Look at the diagram below and describe the arrangement of xylem and phloem in a plant.

Answer 47

Xylem vessels consist of dead cells. They have a thick, strengthened cellulose cell wall with a hollow lumen. On the other hand, phloem consists of columns of living cells. They can be found in the vascular bundles.

Question 48

Describe how transpiration causes water to move in plants.

Answer 48

Water on the surface of spongy and palisade cells (inside the leaf) evaporates and then diffuses out of the leaf throught the stoma. This is called transpiration. As water evaporates, more water is drawn out of the xylem cells inside the leaf to replace what’s lost. As the xylem cells make acontinuous tube from the leaf, down the stem to the roots, this acts like a drinking straw, producing a flow of water and dissolved minerals from roots to leaves.

Question 49

Explain why nitrates, phosphates, potassium and magnesium compounds are needed by plants

Answer 49

Question 50

How would you recognise mineral deficiencies in plants?

Answer 50

Nitrate -Poor growth, yellow leaves. Phosphate -Poor root growth, purple leaves. Potassium- Poor growth of fruit and flowers, yellow leaves with brown spots. Magnesium- Yellow leaves.

Question 51

Recall that minerals are present in the soil in only low amounts

Answer 51

Minerals are present in the soil in only low amounts compareed to the amount of minerals in a plant.

Question 52

Describe how temperature, oxygen and water affect decay.

Answer 52

A warm temperature, moisture and and oxygen will increase decay as these provide the ideal conditions needed for the survival of decay causing micro organisms.

Question 53

What are detritivores?

Answer 53

Detritivores feed on dead and decaying material and they also increase the surface area of the material

Question 54

How can food preservation methods reduce the rate of decay.

Answer 54

Look at the information table below.

Question 55

Explain the advantages and disadvantages of using pesticides.

Answer 55

Advantage- pesticides are sprayed on crops to kill the insects that may reduce crop yield. Disadvantage- some of the chemicals may remain on the surface of, for example, fruit. Others may be absorbed by the plant and therefore be present in the crop.

Question 56

Describe hydroponics and their possible uses.

Answer 56

Hydroponics- Soil is replaced by a mineral solution pumped around the plant roots.
Removing the soil means there’s no risk of soil organisms causing disease but the plants have to be supported. It allows crops to be grown in regions where there’s no soil.

Question 57

Explain the advantages and disadvantages of organic farming and biological control.

Answer 57

Biological control is when a natural predator is introduced to control a pest e.g ladybirds maybe introduced to eat aphids inoder to protect the crop from the pest. Sometimes the introduced predator will effect other animal populations and not prey on the pest species.