Survival And Response Flashcards
Give one similarity and one difference between a taxis and a tropism.
Simularity:
- They are both directional responses to stimulus
Difference:
- Taxis occurs in animals
- Tropisim occurs in plants
Scientists investigated tropisms in the roots of tomato plants.
They grew tomato plants from seeds on vertical agar plates, as shown in Figure 1.
The top of each plate was made of agar gel containing no salt.
The bottom of each plate was made of one of the following:
- agar gel containing no salt
- agar gel containing salt.
Typical results for growth of the roots are shown in Figure 1.
( Figure 1 shows two different growths of plants )
( One image shows a plant with agar gel with no salt in it )
( The other image shows a palnt with agar gel with salt in it at the bottom of the agar plate )
( The diagrams show that the roots of the plant grow but not in the area of salt, so the roots will grow downwards, avoiding the agar gel with salt in it )
What do these results show about the responses of the roots of tomato plants to gravity and salt?
Roots repond to gravity and salt by:
- Roots grow in the direction of gravity
- Roots grow away from salt
- Salt has a greater effect on the growth of roots than gravity
In root tips of tomatoes, IAA is transported out of the cells by a carrier protein.
In roots of tomatoes, high concentrations of IAA inhibit cell elongation.
The scientists’ hypothesis was that salt causes a change in the number of IAA carrier proteins in cells in different parts of the root tip.
Figure 2 shows two cells, L and R, in the root tip of a tomato plant.
( Figure two shows a root tip and two different cells on either side of it )
( Cell “ L “ and “ R “ are the two different cells )
( Cell “ L “ has more carrier proteins than cell “ R “ )
( Salt diffuses in the direction of cell “ L “ )
Explain why this root tip would grow away from salt.
Root tip grows away from salt because:
- Cell “ L “ has more carrier proteins than cell “ R “
- So there’s less IAA in cell “ L “
- So there’s more growith in cell “ L “
A biologist investigated the behaviour of a species of worm that lives in soil.
He cultured three samples of worms in three separate trays of soil for many days.
Each culture:
- contained a food supply
- was kept at a different temperature.
The temperatures of the cultures were 17 °C, 20 °C and 23 °C.
The biologist then removed food from the trays for several hours.
Then he transferred each sample of worms onto a glass surface where there was no food.
Each surface had a temperature gradient across it. After 1 hour, the biologist recorded the position of each
worm.
The figure below shows his results.
On each diagram, ( The circled “ X “ ) marks where he released the worms onto the glass surface.
( Figure shows three images of the same glass surface ranging in temperatures )
( From left to right, the temperature ranges from 17 degrees on the left, 20 degrees on the centre and 23 degrees on the right )
( The circled “ X “ is in the centre of the glass surface )
( On the first image, the worms cultured ( moved and stayed ) at 17 degrees )
( On the second image. the worms cultured at the centre )
( On the third image, the worms cultured at the right )
The biologist concluded that the worms’ behaviour demonstrated taxis.
How do these results support this conclusion?
The results support this conclusion because:
- Taxis is a directional response to a stimulus
- So the worms move towards a temperature they are used to
Using the information provided, suggest an explanation for the worms’ behaviour on
the glass surfaces in the absence of food.
( A biologist investigated the behaviour of a species of worm that lives in soil.
He cultured three samples of worms in three separate trays of soil for many days.
Each culture:
- contained a food supply
- was kept at a different temperature.
The temperatures of the cultures were 17 °C, 20 °C and 23 °C.
The biologist then removed food from the trays for several hours.
Then he transferred each sample of worms onto a glass surface where there was no food.
Each surface had a temperature gradient across it. After 1 hour, the biologist recorded the position of each
worm.
The figure below shows his results.
On each diagram, ( The circled “ X “ ) marks where he released the worms onto the glass surface.
( Figure shows three images of the same glass surface ranging in temperatures )
( From left to right, the temperature ranges from 17 degrees on the left, 20 degrees on the centre and 23 degrees on the right )
( The circled “ X “ is in the centre of the glass surface )
( On the first image, the worms cultured ( moved and stayed ) at 17 degrees )
( On the second image. the worms cultured at the centre )
( On the third image, the worms cultured at the right ) )
The worms’ behaviour on the glass surfaces in the absence of food is:
- In the absence of food, they respond to temperature
- They move towards a temperature they are used to
- Then stay in this temperature
In each experiment, the biologist exposed the surfaces to light that was dim and
even, so he could see where the worms went.
Apart from seeing where the worms went, suggest two reasons why it was
important that the light was dim and even.
( A biologist investigated the behaviour of a species of worm that lives in soil.
He cultured three samples of worms in three separate trays of soil for many days.
Each culture:
- contained a food supply
- was kept at a different temperature.
The temperatures of the cultures were 17 °C, 20 °C and 23 °C.
The biologist then removed food from the trays for several hours.
Then he transferred each sample of worms onto a glass surface where there was no food.
Each surface had a temperature gradient across it. After 1 hour, the biologist recorded the position of each
worm.
The figure below shows his results.
On each diagram, ( The circled “ X “ ) marks where he released the worms onto the glass surface.
( Figure shows three images of the same glass surface ranging in temperatures )
( From left to right, the temperature ranges from 17 degrees on the left, 20 degrees on the centre and 23 degrees on the right )
( The circled “ X “ is in the centre of the glass surface )
( On the first image, the worms cultured ( moved and stayed ) at 17 degrees )
( On the second image. the worms cultured at the centre )
( On the third image, the worms cultured at the right ) )
The two reasons why it was important that the light was dim and even is because:
- Dim light is a normal environment to them
- The light is even because worms might move away from bright light
Stemborers are insect pests that feed on maize plants.
Scientists investigated the effect of push-pull stimuli on the control of these pests.
For this investigation, the scientists divided a large field into plots measuring 50m × 50m.
They then designated each plot as a control plot or a test plot. The following figure shows
what they planted in each type of plot.
( The diagram shows a “ control plot “, which is a maize, 50m × 50m in area )
( The diagram next to it is labelled the “ Test plot “, which is a maize and legume plants in equal numbers )
( The “ Test plot” is still 50m × 50m in area, but on the outside of the plot, there’s a 1m wide strip of a grass species surrounding a 1m of wide strip of bare ground )
( In summary, within the 1m wide strip of a grass species is a 1m of wide strip of bare ground, and within that is the maize and legume plants in equal numbers )
The legumes planted with the maize drive stemborers away.
The grass species attracts stemborers.
The table below shows the scientists’ results.
Plots:
1 ) Control
2 ) Test
Mean percentage damage to maize plants:
1 ) 29.6
2 ) 6.7
Mean maize grain yield / tonnes per hectare ( ± standard deviation ):
1 ) 1.5 ( ±0.2 )
2 ) 3.7 ( ±0.3 )
Mean production costs per farmer / $ per hectare ( ± standard deviation ):
1 ) 250 ( ±0.7 )
2 ) 278 ( ±1.1 )
Mean total income for farmer / $ per hectare ( ± standard deviation )
1 ) 329 ( ±5.9 )
2 ) 679 ( ±10.2 )
In the test plot of land, identify the push stimulus and the pull stimulus.
Push stimulus:
- legume
Pull stimulus:
- Grass
When measuring the mean percentage damage to maize plants, 60 plants from each test plot were selected at random and examined.
Describe how the maize plants could be selected at random.
( Stemborers are insect pests that feed on maize plants.
Scientists investigated the effect of push-pull stimuli on the control of these pests.
For this investigation, the scientists divided a large field into plots measuring 50m × 50m.
They then designated each plot as a control plot or a test plot. The following figure shows
what they planted in each type of plot.
( The diagram shows a “ control plot “, which is a maize, 50m × 50m in area )
( The diagram next to it is labelled the “ Test plot “, which is a maize and legume plants in equal numbers )
( The “ Test plot” is still 50m × 50m in area, but on the outside of the plot, there’s a 1m wide strip of a grass species surrounding a 1m of wide strip of bare ground )
( In summary, within the 1m wide strip of a grass species is a 1m of wide strip of bare ground, and within that is the maize and legume plants in equal numbers )
The legumes planted with the maize drive stemborers away.
The grass species attracts stemborers.
The table below shows the scientists’ results.
Plots:
1 ) Control
2 ) Test
Mean percentage damage to maize plants:
1 ) 29.6
2 ) 6.7
Mean maize grain yield / tonnes per hectare ( ± standard deviation ):
1 ) 1.5 ( ±0.2 )
2 ) 3.7 ( ±0.3 )
Mean production costs per farmer / $ per hectare ( ± standard deviation ):
1 ) 250 ( ±0.7 )
2 ) 278 ( ±1.1 )
Mean total income for farmer / $ per hectare ( ± standard deviation )
1 ) 329 ( ±5.9 )
2 ) 679 ( ±10.2 ) )
Maize plants could be selected at random by:
- Setting up tape measures on two sides of the plot
- Use a random number generator
- To generate coordinates
In the test plot, bare ground was left between the maize and the grass species.
Suggest an explanation why.
( Stemborers are insect pests that feed on maize plants.
Scientists investigated the effect of push-pull stimuli on the control of these pests.
For this investigation, the scientists divided a large field into plots measuring 50m × 50m.
They then designated each plot as a control plot or a test plot. The following figure shows
what they planted in each type of plot.
( The diagram shows a “ control plot “, which is a maize, 50m × 50m in area )
( The diagram next to it is labelled the “ Test plot “, which is a maize and legume plants in equal numbers )
( The “ Test plot” is still 50m × 50m in area, but on the outside of the plot, there’s a 1m wide strip of a grass species surrounding a 1m of wide strip of bare ground )
( In summary, within the 1m wide strip of a grass species is a 1m of wide strip of bare ground, and within that is the maize and legume plants in equal numbers )
The legumes planted with the maize drive stemborers away.
The grass species attracts stemborers.
The table below shows the scientists’ results.
Plots:
1 ) Control
2 ) Test
Mean percentage damage to maize plants:
1 ) 29.6
2 ) 6.7
Mean maize grain yield / tonnes per hectare ( ± standard deviation ):
1 ) 1.5 ( ±0.2 )
2 ) 3.7 ( ±0.3 )
Mean production costs per farmer / $ per hectare ( ± standard deviation ):
1 ) 250 ( ±0.7 )
2 ) 278 ( ±1.1 )
Mean total income for farmer / $ per hectare ( ± standard deviation )
1 ) 329 ( ±5.9 )
2 ) 679 ( ±10.2 ) )
Bare ground was left between the maize and the grass species because:
- It prevents competition between the maize and grass
- To prevent competition with nutrients
The legume plants have nodules containing nitrogen-fixing bacteria on their roots.
Explain how nitrogen-fixing bacteria could increase the growth of the maize.
( Stemborers are insect pests that feed on maize plants.
Scientists investigated the effect of push-pull stimuli on the control of these pests.
For this investigation, the scientists divided a large field into plots measuring 50m × 50m.
They then designated each plot as a control plot or a test plot. The following figure shows
what they planted in each type of plot.
( The diagram shows a “ control plot “, which is a maize, 50m × 50m in area )
( The diagram next to it is labelled the “ Test plot “, which is a maize and legume plants in equal numbers )
( The “ Test plot” is still 50m × 50m in area, but on the outside of the plot, there’s a 1m wide strip of a grass species surrounding a 1m of wide strip of bare ground )
( In summary, within the 1m wide strip of a grass species is a 1m of wide strip of bare ground, and within that is the maize and legume plants in equal numbers )
The legumes planted with the maize drive stemborers away.
The grass species attracts stemborers.
The table below shows the scientists’ results.
Plots:
1 ) Control
2 ) Test
Mean percentage damage to maize plants:
1 ) 29.6
2 ) 6.7
Mean maize grain yield / tonnes per hectare ( ± standard deviation ):
1 ) 1.5 ( ±0.2 )
2 ) 3.7 ( ±0.3 )
Mean production costs per farmer / $ per hectare ( ± standard deviation ):
1 ) 250 ( ±0.7 )
2 ) 278 ( ±1.1 )
Mean total income for farmer / $ per hectare ( ± standard deviation )
1 ) 329 ( ±5.9 )
2 ) 679 ( ±10.2 ) )
Nitrogen-fixing bacteria could increase the growth of the maize:
- Nitrogen-fixing bacteria convert nitrogen from the air, into ammonium compounds, which are then converted into nitrates ( Nitrification )
- Maize uses nitrates in the soil for amino acid production
A year after this investigation, the government of one country decided that their farmers should use these push-pull stimuli.
How do these data support this decision?
( Stemborers are insect pests that feed on maize plants.
Scientists investigated the effect of push-pull stimuli on the control of these pests.
For this investigation, the scientists divided a large field into plots measuring 50m × 50m.
They then designated each plot as a control plot or a test plot. The following figure shows
what they planted in each type of plot.
( The diagram shows a “ control plot “, which is a maize, 50m × 50m in area )
( The diagram next to it is labelled the “ Test plot “, which is a maize and legume plants in equal numbers )
( The “ Test plot” is still 50m × 50m in area, but on the outside of the plot, there’s a 1m wide strip of a grass species surrounding a 1m of wide strip of bare ground )
( In summary, within the 1m wide strip of a grass species is a 1m of wide strip of bare ground, and within that is the maize and legume plants in equal numbers )
The legumes planted with the maize drive stemborers away.
The grass species attracts stemborers.
The table below shows the scientists’ results.
Plots:
1 ) Control
2 ) Test
Mean percentage damage to maize plants:
1 ) 29.6
2 ) 6.7
Mean maize grain yield / tonnes per hectare ( ± standard deviation ):
1 ) 1.5 ( ±0.2 )
2 ) 3.7 ( ±0.3 )
Mean production costs per farmer / $ per hectare ( ± standard deviation ):
1 ) 250 ( ±0.7 )
2 ) 278 ( ±1.1 )
Mean total income for farmer / $ per hectare ( ± standard deviation )
1 ) 329 ( ±5.9 )
2 ) 679 ( ±10.2 ) )
( Push stimulus:
- legume
Pull stimulus:
- Grass )
These data support this decision because:
- There is reduced percentage in damage to Maize plants ( from the table )
- Standard deviations in the results don’t overlap but need statistics to show significance of this difference ( From the table )
- There’s more profit than additional costs ( From the table )
Scientists investigated the response of lateral roots to gravity. Lateral roots grow from the side of main roots.
The diagrams show four stages, A to D, in the growth of a lateral root and typical cells from the tip of the lateral root in each stage.
All of the cells are drawn with the bottom of the cell towards the bottom of the page.
( There are 4 diagrams, labelled, “ Stage A, B C and D “ respectively )
( Each “ Stage “ shows a diagram of the plant’s root and a cell from the tip of that root )
( In “ Stage A “, the root is growing to the right, in a straight line )
( The cell from the tip of this root only has a nucleus )
( In “ Stage B “, the end of the root is starting to grow downwards )
( A cell from the tip of this root contains starch grains in addition to the nucleus )
( In “ Stage C “, the root has grown more downwards )
( The cell from the root tip has now gained a vacuole and more starch grains )
( In “ Stage D”, the root is now growing parellel to a y-axis, so it’s growing straight down )
( The cell from the root tip has it’s starch grains towards the bottom of the cell, in the direction in which the root is growing )
Describe three changes in the root tip cells between stages A and D.
Three changes in the root tip cells between stages A and D are:
- The formation of a vacuole
- Formation of starch grains
- The movement of grains towards the bottom of the cell
The scientists’ hypothesis was that there was a relationship between the starch grains in the root tip cells and the bending and direction of growth of lateral roots.
Does the information in the diagram support this hypothesis?
Give reasons for your answer.
( Scientists investigated the response of lateral roots to gravity. Lateral roots grow from the side of main roots.
The diagrams show four stages, A to D, in the growth of a lateral root and typical cells from the tip of the lateral root in each stage.
All of the cells are drawn with the bottom of the cell towards the bottom of the page.
( There are 4 diagrams, labelled, “ Stage A, B C and D “ respectively )
( Each “ Stage “ shows a diagram of the plant’s root and a cell from the tip of that root )
( In “ Stage A “, the root is growing to the right, in a straight line )
( The cell from the tip of this root only has a nucleus )
( In “ Stage B “, the end of the root is starting to grow downwards )
( A cell from the tip of this root contains starch grains in addition to the nucleus )
( In “ Stage C “, the root has grown more downwards )
( The cell from the root tip has now gained a vacuole and more starch grains )
( In “ Stage D”, the root is now growing parellel to a y-axis, so it’s growing straight down )
( The cell from the root tip has it’s starch grains towards the bottom of the cell, in the direction in which the root is growing )
)
Information in the diagram supports this hypothesis because:
- The root grows sideways before the starch grains form
- The root bends after the starch grains have formed
- There’s more bending as grains increase in number
The diagram shows the distribution of indoleacetic acid ( IAA ) in the lateral root at Stage B.
( The diagram shows a high concentration of IAA towards the side of the root bending )
( It also shows a low concentration of IAA on the other side of the root )
Explain how this distribution of IAA causes the root to bend.
( Scientists investigated the response of lateral roots to gravity. Lateral roots grow from the side of main roots.
The diagrams show four stages, A to D, in the growth of a lateral root and typical cells from the tip of the lateral root in each stage.
All of the cells are drawn with the bottom of the cell towards the bottom of the page.
( There are 4 diagrams, labelled, “ Stage A, B C and D “ respectively )
( Each “ Stage “ shows a diagram of the plant’s root and a cell from the tip of that root )
( In “ Stage A “, the root is growing to the right, in a straight line )
( The cell from the tip of this root only has a nucleus )
( In “ Stage B “, the end of the root is starting to grow downwards )
( A cell from the tip of this root contains starch grains in addition to the nucleus )
( In “ Stage C “, the root has grown more downwards )
( The cell from the root tip has now gained a vacuole and more starch grains )
( In “ Stage D”, the root is now growing parellel to a y-axis, so it’s growing straight down )
( The cell from the root tip has it’s starch grains towards the bottom of the cell, in the direction in which the root is growing )
)
This distribution of IAA causes the root to bend because:
- Where IAA concentration is high, it inhibits the elongation of cells
- Where IAA concentration is low, it promotes elongation of cells
Scientists investigated the response of the roots of pea seedlings to gravity.
They took three samples of seedlings, A, B, and C, and placed them so that their roots were growing horizontally.
The root tips of each sample had been given different treatments. After a set time, the scientists recorded whether the roots of the seedlings had grown upwards or downwards and the amount of curvature.
The table shows the treatment they gave to each sample and their results.
Treatment: ( These are also shown with diagrams )
A ) None
B ) Root tip is removed
C ) Upper half of root tip is removed
Results
Direction of growth:
A ) Downwards
B ) Contines to grow horizontally
C ) Downwards
Mean amount of curvature / degrees
A ) 60
B ) 0
C ) 30
The pea seedlings were kept in the dark after each treatment. Explain why this was necessary.
Pea seedlings were kept in the dark after each treatment, this is necessary because:
- Seedlings respond to light
