SCSA Biology Science as a Human Endeavour
6 sample questions with marking guides and sample answers · Avg. score: 91.3%
Urban areas are susceptible to epidemics primarily because they
are unhygienic.
are densely populated.
have many vectors.
have antibiotic-resistant pathogens.
Reveal Answer
are unhygienic.
While poor sanitation can exacerbate disease spread, modern urban areas often have advanced sanitation infrastructure, making this an incorrect primary cause.
are densely populated.
High population density in urban areas increases the frequency of close contact between individuals, which facilitates the rapid transmission of infectious diseases.
have many vectors.
Disease vectors, such as mosquitoes or ticks, are often more abundant in rural or natural environments rather than urban areas.
have antibiotic-resistant pathogens.
While antibiotic resistance is a serious medical concern, it is a global issue not unique to cities and does not primarily drive the initial rapid spread of an epidemic.
In Western Australia, permits are required to move honeybees, honey and bee-keeping equipment between regions within the State. The main reason for this regulation is to
reduce competition between honeybees and native bees.
ensure that honeybees are available to pollinate crops.
limit the spread of honeybee pathogens.
regulate the number of honeybees present in a region.
Reveal Answer
reduce competition between honeybees and native bees.
While competition between honeybees and native bees occurs, movement permits are primarily implemented for biosecurity purposes, not to manage ecological competition.
ensure that honeybees are available to pollinate crops.
Movement restrictions actually regulate and potentially limit the transport of bees, rather than ensuring their availability for crop pollination.
limit the spread of honeybee pathogens.
The primary purpose of these biosecurity regulations is to prevent the introduction and spread of devastating honeybee diseases and pests between regions.
regulate the number of honeybees present in a region.
The permit system is designed for disease control and biosecurity, not to manage or cap the total population of honeybees in specific areas.
The Varroa mite is an external parasite of European honey bees and is considered to be the most serious pest of honey bees worldwide.
Why is Varroa mite infection considered to be an infectious disease?
Reveal Answer
Varroa mite is an infectious disease because the mite is a parasitic pathogen that is spread between bees and hives that come into direct contact with the pest.
| Descriptor | Marks |
|---|---|
Provides justification for Varroa mite infection being an infectious disease | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
In June 2022, the Varroa mite was detected for the first time in Australia at the Port of Newcastle. It then spread to surrounding areas.
Explain TWO procedures that could have been employed to prevent the spread of the Varroa mite in honey bees.
Reveal Answer
Measures used to prevent the spread of Varroa mite include:
- Early identification of Varroa mite infestation ensures early detection and isolation of infected bee populations. This will stop them from spreading to healthy bees
- Destroy infected hives. This will kill the mites and infected bees, preventing the spread of the mite to healthy hives.
| Descriptor | Marks |
|---|---|
Explains TWO procedures used to prevent the spread of Varroa mite | 4 |
| 3 |
| 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Xerophytic plants need to maintain water balance while allowing for gas exchange, and have a variety of adaptations to achieve this.
Explain why plants lose water to the environment during gas exchange and three distinctly different ways in which xerophytic plants minimise water loss from gas exchange.
Reveal Answer
Gas exchange occurs through stomata, which are pores in the leaf. When stomata are open, water is lost from the plant via transpiration/evaporation.
Ways to minimise water loss from gas exchange are (any 3 of):
- Reduced stomata size, such that there's smaller area to lose water through.
- Sunken stomata, which increases humidity around stomatal pore.
- Closing stomata during the day, when temperatures are higher.
- Rolled leaves, which protect stomata from the environment.
Water loss during gas exchange
| Descriptor | Marks |
|---|---|
gas exchange occurs through (open) stomata or plants release oxygen/take in carbon dioxide through (open) stomata | 1 |
stomata are pores in the leaf (that are surrounded by guard cells) | 1 |
water/water vapour is lost from plant when stomata are open | 1 |
via transpiration or evaporation | 1 |
Minimising water loss 1
| Descriptor | Marks |
|---|---|
Identifies a valid strategy to minimise water loss (e.g., fewer stomata/reduced size, sunken stomata/hairs in pit/rolled leaves, stomata open at night/close during day, less stomata on upper surface/more on lower surface) | 1 |
Provides the corresponding explanation for how the identified strategy minimises water loss (e.g., fewer openings/smaller area, increases humidity/creates humid microclimate, open when temperatures are lower, protects stomata from environment/wind/sunlight) | 1 |
Minimising water loss 2
| Descriptor | Marks |
|---|---|
Identifies a valid strategy to minimise water loss (e.g., fewer stomata/reduced size, sunken stomata/hairs in pit/rolled leaves, stomata open at night/close during day, less stomata on upper surface/more on lower surface) | 1 |
Provides the corresponding explanation for how the identified strategy minimises water loss (e.g., fewer openings/smaller area, increases humidity/creates humid microclimate, open when temperatures are lower, protects stomata from environment/wind/sunlight) | 1 |
Minimising water loss 3
| Descriptor | Marks |
|---|---|
Identifies a valid strategy to minimise water loss (e.g., fewer stomata/reduced size, sunken stomata/hairs in pit/rolled leaves, stomata open at night/close during day, less stomata on upper surface/more on lower surface) | 1 |
Provides the corresponding explanation for how the identified strategy minimises water loss (e.g., fewer openings/smaller area, increases humidity/creates humid microclimate, open when temperatures are lower, protects stomata from environment/wind/sunlight) | 1 |
The chance of an epidemic occurring depends on several factors.
Using influenza as an example, explain why urban areas are susceptible to epidemics and how vaccination and three other healthcare provisions can reduce disease transmission.
Reveal Answer
Influenza is easily spread via direct contact or airborne particles. Urban areas have high population density, which increases disease transmission, as uninfected people are more likely to come into contact with an infected person. Increased travel to urban areas also increases the chance of introducing a new strain with little resistance in the population.
Vaccines give people immunity without catching the disease, which reduces the chances of an individual catching the disease even if they are in contact with an infected individual. The spread of disease will slow if a large proportion of the population are vaccinated.
Other healthcare provisions include education about good hygiene. Healthcare can implement quarantine of infected people, and provide antiviral medication to reduce the severity and duration of symptoms. Monitoring and reporting can result in early detection and early implementation of control measures.
Urban areas
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 4 of): | 4 |
Vaccinations
| Descriptor | Marks |
|---|---|
States that vaccines give people immunity (without catching the disease) | 1 |
Explains that vaccination reduces the chances of an individual catching the disease (even if they are in contact with an infected individual) | 1 |
Describes that the spread of disease will slow/transmission will be reduced if a large proportion of the population are vaccinated/immune/with herd immunity | 1 |
Other healthcare provisions
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 3 of):
| 3 |
The pathogen that causes jarrah dieback is a type of protist.
In order to prevent the spread of jarrah dieback, vehicles are banned from driving on some tracks when the soil is wet.
List two structural features of protists that are not found in bacteria.
Reveal Answer
Protists are eukaryotes and membrane-bound organelles.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |
List two structural features of protists that are not found in fungi.
Reveal Answer
Protists are usually unicellular and often have flagella.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |
Explain how this can prevent the spread of jarrah dieback.
Reveal Answer
The disease is spread from plant to plant by spores, which are more active when it is wet. Vehicles pick up more contaminated soil when it is wet, therefore the risk of transmission is greater when the soil is wet. Furthermore, vehicles can spread the disease over a large area.
| Descriptor | Marks |
|---|---|
Identifies that the disease is spread (from plant to plant) by spores/zoospores | 1 |
States that spores/zoospores are more active when it is wet | 1 |
Explains that vehicles pick up more (contaminated) soil when it is wet, therefore the risk of transmission/spread is greater when the soil is wet | 1 |
Describes that vehicles can spread the disease/spores/zoospores over a large area | 1 |
Describe how the tuberculosis pathogen is transmitted to a new host.
Reveal Answer
The pathogen is airborne and a new host inhales the pathogen.
| Descriptor | Marks |
|---|---|
States that the pathogen is in the air/airborne OR affected individuals breathe out the pathogen/droplet | 1 |
States that a new host breathes in/inhales the pathogen | 1 |
Describe the impact that the tuberculosis pathogen has on the host.
Reveal Answer
The pathogen infects the lungs and causes coughing.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |
Explain how vaccination helps to control the spread of tuberculosis.
Reveal Answer
Vaccination introduces a weakenedversion of a pathogen into the body, which stimulates the production of antibodies. Vaccinated individuals become immune. The higher the proportion of the population that is immune, the greater the protection.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 4 of):
| 4 |
When travellers enter Australia from overseas, they are required to declare all plant and animal matter that they have brought with them. Explain why.
Reveal Answer
This is biosecurity measure that protects the agricultural industry. It stops the introduction of exotic pests found in other countries but not in Australia. Plant and animal matter found to be infected will either be treated with pesticides or insecticides, or destroyed.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 4 of):
| 4 |
Measles in Samoa
Measles is one of the most contagious viruses affecting humans. Measles spreads when an infected person coughs or sneezes and the virus is breathed in by another person, or by direct contact with bodily fluids. In a susceptible population – people who have neither been vaccinated nor had measles previously – one person with measles could infect 12 to 18 other people.
The Pacific island nation of Samoa had a significant measles outbreak in 2019. This started when a person who had measles arrived in Samoa by plane in August 2019. In the following months over 5000 measles cases were recorded and more than 70 people died.
A measles outbreak was declared by the Samoan Government in October 2019. On 15 November the Samoan Government declared a 30-day state of emergency as the number of measles cases continued to rise and more people died. Ninety per cent of the deaths were among children less than five years old. More than one in five Samoan babies aged six to 11 months contracted measles during this outbreak and more than one in 150 babies in this age group died. Fewer deaths occurred in babies who were less than six months old.
Prior to the measles outbreak in Samoa, the vaccination rate for measles for five-year-old children in the country had fallen to 31% in 2018. One of the responses of the government to the outbreak was a mandatory vaccination program for all people. By early December 2019 over 90% of the population had been vaccinated.
In Australia a measles-containing vaccine (MMR vaccine) is recommended for children aged 12 months of age or older. A single dose of the measles vaccine provides protection for between 95% and 98% of recipients, while two doses protects 99% of vaccinated people. In 2018 in Australia, 95% of five-year-old Australian children were fully vaccinated.
People who are vaccinated are unlikely to be affected by the measles virus.
Is the measles outbreak discussed in the article above best described as an epidemic or a pandemic? Give your reasoning.
Reveal Answer
The outbreak is best described as an epidemic as it is contained within the region of Samoa and did not spread globally over multiple countries or continents.
| Descriptor | Marks |
|---|---|
Identifies the outbreak as an epidemic. | 1 |
States that it is contained within the region of Samoa and did not spread globally. | 1 |
Consider the Samoan children who were less than five years old during the measles outbreak. Of this group, what age were the children who were least likely to die from measles? Explain why children of this age would be less likely to die.
Reveal Answer
The age of the students less likely to die from measles was under six months old.
These children are protected by passive natural immunity.
| Descriptor | Marks |
|---|---|
Identifies the age as under six months old. | 1 |
Provides a valid reason (e.g., protected by passive natural immunity, breastfeeding, or less contact with people/reduced mobility). | 1 |
What is the percentage difference between vaccinated five-year-old children in Samoa and Australia in 2018?
Reveal Answer
64 per cent
| Descriptor | Marks |
|---|---|
Calculates the percentage difference as 64 per cent. | 1 |
The MMR vaccine contains antigens for measles, mumps and rubella.
What form of immunity is given when a person is vaccinated with the MMR vaccine?
Reveal Answer
The type of immunity is artificial and active.
| Descriptor | Marks |
|---|---|
Identifies the form of immunity as artificial and active. | 1 |
Some children, for example those undergoing chemotherapy, cannot be vaccinated.
Explain how high vaccination rates can also protect unvaccinated individuals.
Reveal Answer
For example:
-
Herd immunity occurs.
-
High vaccination rates reduce the number of susceptible hosts.
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |
Describe two strategies, other than vaccination, that could reduce the transmission of measles.
Reveal Answer
| Descriptor | Marks |
|---|---|
1 mark for each correct point (any 2 of):
| 2 |