Use coordination evidence from plant and animal questions: plan stimulus investigations, interpret response data and explain nerves or hormones.
The diagram shows a food web from a woodland ecosystem.
Woodlice feed on dead and decaying plant material in the soil. The photographs show how a woodlouse can curl up into a ball.
This behaviour is an example of a reflex response.
State what is meant by a reflex response.
Give a reason why this reflex response benefits the woodlouse.
Read the passage below. Use the information in the passage and your own knowledge to answer the questions that follow.
Rivers - the arteries of the world
Rivers are important supplies of water for drinking, farming, industry, and leisure activities. Like our circulatory system, rivers are essential for transport, and have a homeostatic effect on nature. The biodiversity in rivers is high as they are the habitat for many different species. In many countries rivers are under threat from human impact, particularly the release of untreated sewage.
Flooding can cause untreated sewage to run into rivers from pipelines. Scientists estimated that in England and Wales during 2022, sewage was released into rivers for a total time of 300000 hours. This sewage came from 1200 different pipelines. Untreated sewage may contain fertilisers, pesticides, pathogenic bacteria, and pharmaceutical drugs.
The photograph shows sewage being released into a river. The sewage causes the growth of something called 'sewage fungus'. Sewage fungus looks like fungus but is a solid collection of several types of anaerobic bacteria. Sewage fungus is common in rivers that are polluted with untreated sewage or are near to cattle and intensive crop farms. If sewage fungus is found in a river it often indicates that the biodiversity of the river will be low.
Pesticides from agriculture are also released into rivers, and these are frequently transferred through natural food chains. Even pharmaceutical drugs, such as those containing the hormones oestrogen and progesterone, have been found in polluted rivers. These drugs must have been consumed by humans, excreted and then released into the sewage flowing into rivers.
Untreated sewage can also contain pathogenic species of bacteria that then enter rivers. If humans are infected with these bacteria, the large intestine absorbs less water, causing diarrhoea. Some of the bacteria found in sewage are resistant to antibiotics.
Scientists are looking for ways to prevent river pollution. One way is to reduce the risk of pollution from fertilisers and from cattle urine and faeces. Woodchip bioreactors are being trialled in agricultural fields that are near to rivers. These bioreactors are pits filled with woodchips and denitrifying bacteria. Water drains through these bioreactors, which helps to remove nitrates before they reach the rivers. In some countries, efforts are being made to replant forests in areas upstream of rivers to reduce river flooding and the risk of untreated sewage release.
Rivers have a homeostatic effect on nature. This is similar to the role of homeostasis in humans.
State what is meant by the term homeostasis (lines 2 and 3).
Oestrogen and progesterone in polluted water lower the levels of FSH and LH in mammals.
State why lower levels of FSH can reduce fertility in mammals.
State why lower levels of LH can reduce fertility in mammals.
The diagram shows a human reflex arc with some structures labelled. It is the withdrawal reflex, which allows a person to remove their hand from a hot object quickly.
Which structure is the sensory receptor?
L
P
Q
S
Which structure is the cell body of the relay neurone?
L
N
M
P
Which structure is the motor neurone?
L
M
R
S
Which structure is the effector?
L
M
Q
S
A nerve impulse travels at 50 metres per second.
The length of the nerve pathway in the withdrawal reflex arc is 180 cm .
The time a person takes to remove their hand away from a hot object is called the response time.
Explain why the actual response time is different from the time taken for a nerve impulse to travel 180 cm .
The diagram shows a food web from a woodland ecosystem.
Woodlice feed on dead and decaying plant material in the soil. The photographs show how a woodlouse can curl up into a ball.
This behaviour is an example of a reflex response.
Give a reason why this reflex response benefits the woodlouse.
Read the passage below. Use the information in the passage and your own knowledge to answer the questions that follow.
Rivers - the arteries of the world
Rivers are important supplies of water for drinking, farming, industry, and leisure activities. Like our circulatory system, rivers are essential for transport, and have a homeostatic effect on nature. The biodiversity in rivers is high as they are the habitat for many different species. In many countries rivers are under threat from human impact, particularly the release of untreated sewage.
Flooding can cause untreated sewage to run into rivers from pipelines. Scientists estimated that in England and Wales during 2022, sewage was released into rivers for a total time of 300000 hours. This sewage came from 1200 different pipelines. Untreated sewage may contain fertilisers, pesticides, pathogenic bacteria, and pharmaceutical drugs.
The photograph shows sewage being released into a river. The sewage causes the growth of something called 'sewage fungus'. Sewage fungus looks like fungus but is a solid collection of several types of anaerobic bacteria. Sewage fungus is common in rivers that are polluted with untreated sewage or are near to cattle and intensive crop farms. If sewage fungus is found in a river it often indicates that the biodiversity of the river will be low.
Pesticides from agriculture are also released into rivers, and these are frequently transferred through natural food chains. Even pharmaceutical drugs, such as those containing the hormones oestrogen and progesterone, have been found in polluted rivers. These drugs must have been consumed by humans, excreted and then released into the sewage flowing into rivers.
Untreated sewage can also contain pathogenic species of bacteria that then enter rivers. If humans are infected with these bacteria, the large intestine absorbs less water, causing diarrhoea. Some of the bacteria found in sewage are resistant to antibiotics.
Scientists are looking for ways to prevent river pollution. One way is to reduce the risk of pollution from fertilisers and from cattle urine and faeces. Woodchip bioreactors are being trialled in agricultural fields that are near to rivers. These bioreactors are pits filled with woodchips and denitrifying bacteria. Water drains through these bioreactors, which helps to remove nitrates before they reach the rivers. In some countries, efforts are being made to replant forests in areas upstream of rivers to reduce river flooding and the risk of untreated sewage release.
Rivers have a homeostatic effect on nature. This is similar to the role of homeostasis in humans.
State what is meant by the term homeostasis (lines 2 and 3).
The body has a hormonal control system that coordinates some of the body's responses.
Plants also respond to changes in their environment.
In many plants, flowering is stimulated by the number of hours of daylight.
Suggest why flowering in many plants is stimulated by the number of hours of daylight rather than by temperature.
The body has a hormonal control system that coordinates some of the body's responses.
Plants also respond to changes in their environment.
Explain how plants benefit from the responses of their roots and stems to the direction of light they receive.
Plants respond to stimuli.
Some of these responses are called tropic responses.
Describe the role of auxin in plant responses to light.
Fur colour in rats is controlled by a gene with two alleles.
One allele codes for black fur colour. The other allele codes for agouti fur colour.
Several female rats with agouti coloured fur are mated with several male rats with black coloured fur.
All of the offspring have agouti coloured fur.
Scientists observed that genes that control fur colour in rats can affect rat behaviour, such as how tame they are.
Other genes that control the size of the adrenal glands and the production of neurotransmitters also affect rat behaviour.
Scientists also noticed that coat colour is associated with differences in anatomy and physiology, such as the size of the adrenal glands and the production of neurotransmitters.
Explain why the size of the adrenal glands and the production of neurotransmitters would affect rat behaviour.
Reflexes are responses that protect the body and involve the central nervous system (CNS).
Give the name of one part of the CNS.
Neurones transmit nerve impulses.
The diagram shows a neurone.
Some neurones do not have a myelin sheath.
A scientist investigates the impulse speed for neurones with different diameters. She does this for neurones with a myelin sheath and neurones without a myelin sheath.
The graph shows the scientist's results.
Impulse speed in m per s
Which conclusion is supported by the graph?
impulses are always faster in neurones with a myelin sheath
neurones always have a myelin sheath
wider neurones have a myelin sheath
wider neurones have faster impulses
Multiple sclerosis is a condition that can slow down the speed at which electrical impulses travel along neurones.
The time taken for the blink reflex to occur can be used to help diagnose if someone has multiple sclerosis.
The blink reflex causes the eyelid to close.
Air is blown on to the eye and the time taken for the eyelid to close is recorded.
The diagram shows the reflex pathway.
The speed the impulse moves along the reflex arc consisting of all three neurones in a person without multiple sclerosis is 77 metres per second.
The time taken for the blink reflex to occur in a person with multiple sclerosis is 0.0050 s .
The total length of the neurones in the reflex arc for the person with multiple sclerosis is 25 cm .
The speed of an impulse along the axon of the motor neurone for someone without multiple sclerosis is 120 metres per second.
Suggest why the speed of the impulse calculated along all three neurones is less than the speed of the impulse along only the motor neurone.
Reflexes are responses that protect the body and involve the central nervous system (CNS).
If an animal steps on a sharp object, a reflex arc occurs so that it picks up its foot to prevent further damage.
Describe how named neurones bring about a withdrawal reflex to protect the animal from damage.
The diagram shows the structure of a human eye.
Which of these is the structure labelled X ?
conjunctiva
cornea
lens
retina
Fur colour in rats is controlled by a gene with two alleles.
One allele codes for black fur colour. The other allele codes for agouti fur colour.
Several female rats with agouti coloured fur are mated with several male rats with black coloured fur.
All of the offspring have agouti coloured fur.
Some rats with white fur also have pink eyes.
These rats have pink eyes because they do not have pigment in their irises.
This means that their irises let light pass through, unlike the coloured irises found in other rats.
Explain how this difference in the iris affects vision in the rats with pink eyes.
The skin is an organ involved in temperature regulation.
The diagram shows a section of human skin.
Explain how the skin capillaries regulate body temperature when the body temperature increases.
Animals produce hormones to communicate between cells.
Which hormone causes an increased blood flow to the muscles during exercise?
adrenaline
insulin
progesterone
testosterone