NESA Biology Problem Solving
2 sample questions with marking guides and sample answers · Avg. score: 62.7%
The table shows data from a transect study along a sand dune.
| Zone | ||||
|---|---|---|---|---|
| A | B | C | D | |
| Distance from sea (m) | 0–100 | >100–150 | >150–250 | >250–300 |
| Age of dune (years) | 0–50 | >50–100 | >100–125 | >125–150 |
| pH of soil | 8.4 | 7.4 | 6.9 | 6.0 |
| Organic matter in soil (%) | 1 | 2.5 | 5 | 30 |
| Number of grass species | 2 | 4 | 6 | 2 |
| Number of tree species | 0 | 1 | 3 | 8 |
Contrast species richness in zones A and D. Refer to data in your response.
Reveal Answer
Species richness is five times higher in zone D than zone A. Zone A has two different species, whereas zone D has 10.
| Descriptor | Marks |
|---|---|
Identifies species richness is higher in zone D | 1 |
Provides appropriate data | 1 |
Infer how organic matter affects the pH of soil. Justify your response.
Reveal Answer
As organic matter increased from 1% to 30%, the pH decreased from 8.4 to 6. This suggests that organic matter lowers soil pH.
| Descriptor | Marks |
|---|---|
Infers that organic matter lowers soil pH | 1 |
Justifies response using data | 1 |
Predict which zone would have the highest proportion of K-selected species. Explain your reasoning.
Reveal Answer
Zone D. Zone D is the oldest dune and has the highest species richness. This suggests it may be further along in succession. The number of K-selected species tends to increase as succession progresses.
| Descriptor | Marks |
|---|---|
Predicts zone D | 1 |
Provides appropriate reasoning | 1 |
The following table provides information on three commonly grown genetically modified (GM) crops in Australia.
| Crop | Genetic modification | Characteristic given by modification |
|---|---|---|
| GM cotton | several bacterial genes inserted | insect resistance and herbicide tolerance |
| GM canola | two genes from two different bacterial species inserted | tolerance to several herbicides |
| GM safflower | a selection of genes silenced within the safflower genome | elevated levels of oleic acid in its seeds |
Select one of the GM crops in the table above and justify whether or not this crop could be described as transgenic.
Reveal Answer
An acceptable answer was one of the following:
- genetically modified (GM) cotton is transgenic as it contains genes from other species OR bacteria.
- GM canola is transgenic as it contains genes from other species OR bacteria.
- GM safflower is not transgenic as it does not contain genes from another species.
| Descriptor | Marks |
|---|---|
Provides a correct explanation of why the selected crop is or is not transgenic (e.g., GM cotton/canola is transgenic as it contains genes from other species/bacteria, OR GM safflower is not transgenic as it does not contain genes from another species) | 1 |
One issue with GM canola is the accidental release, during transport, of seeds along roadsides. Usually, unwanted plants that grow on the side of the road are killed using the herbicide glyphosate. However, GM canola is resistant to glyphosate.
Suggest one practical solution for treating GM canola that is found growing along roadsides.
Reveal Answer
An acceptable answer was one of the following:
- use a different herbicide that the GM canola is not resistant to
- remove by mowing
- pick the GM canola growing by the side of the road by hand
- use controlled burning.
| Descriptor | Marks |
|---|---|
Provides a correct practical solution to remove the GM canola (e.g., use a different herbicide, remove by mowing, pick by hand, use controlled burning) | 1 |
A new GM canola crop has been approved for use in Australia. It contains increased levels of omega-3 fatty acids, which are important, in humans, for building healthy cell membranes and for general growth and development, and also protect against a wide variety of diseases.
Omega-3 has traditionally been sourced from fish. Due to the growing demand for sources of omega-3, bioengineers have been encouraged to continue developing GM canola crops as a sustainable alternative.
Discuss one social implication and one biological implication of using GM canola with increased levels of omega-3. Use a different implication in each response.
Reveal Answer
Social implication
The correct answer was any one of the following:
- Farmers who grow non-GM canola may sell more canola and the farmer may have an improved quality of life OR may sell less canola and have a decreased quality of life.
- Improved nutrition for consumers and therefore less demand on the health system.
- More people have access to better nutrition as GM canola is cheaper OR more accessible than fish.
- There could be a decreased consumption of fish, which results in fish farmers making less money and having a lower quality of life.
- Consumers may not want to consume GM food. This could lead to consumers not buying enough GM canola and farmers having a lower quality of life.
Biological implication
Accepted responses included any one of the following:
- Possible crossbreeding with non-GM canola crops leading to a change in genome of the crops.
- Potential lack of genetic variation within the GM canola crop. All GM canola plants could then die if there is a change in a selection pressure.
- Consumers may not want to eat or purchase any GM products as these consumers are concerned it is not safe to eat.
- Less fish consumed reduces overfishing, leading to an increase in the fish population.
- Improved nutrition for consumers improves health outcomes for consumers.
Social Implication
| Descriptor | Marks |
|---|---|
Identifies a valid social implication (e.g., economic impact on farmers, improved nutrition for consumers, access to cheaper nutrition) | 1 |
Explains the social implication (e.g., improved/decreased quality of life, less demand on the health system) | 1 |
Biological Implication
| Descriptor | Marks |
|---|---|
Identifies a valid biological implication (e.g., crossbreeding with non-GM crops, lack of genetic variation, impact on fish populations, health outcomes) | 1 |
Explains the biological implication (e.g., change in genome, susceptibility to selection pressures, reduces overfishing, improves health) | 1 |