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Just over fifty years ago the myxoma virus was brought to Ireland - Leaving Cert Biology - Question b - 2008
Question b
Just over fifty years ago the myxoma virus was brought to Ireland. The disease for which it is responsible in rabbits, myxomatosis, quickly decimated the wild popula... show full transcript
Worked Solution & Example Answer:Just over fifty years ago the myxoma virus was brought to Ireland - Leaving Cert Biology - Question b - 2008
Step 1
Why do you think that the rabbit population was decimated when the myxoma virus was first brought to Ireland?
Answer
The rabbit population was decimated due to a lack of immunity against the myxoma virus. When the virus was introduced, the rabbits had not previously been exposed to it, and thus there was no existing resistance. The rapid spread facilitated by suitable vectors, like fleas, coupled with a high population density of rabbits, led to widespread infection and high mortality rates.
Step 2
Suggest a reason why myxomatosis is no longer a major threat to the Irish rabbit population.
Answer
One reason myxomatosis is no longer a major threat to the Irish rabbit population is the development of natural immunity in rabbits. Over time, the surviving rabbits that were exposed to the virus may have developed immunity, allowing them to reproduce and pass on this resistance to their offspring.
Step 3
Suggest one advantage and one disadvantage of biological control.
Answer
An advantage of biological control is that it can be environmentally friendly since it often uses natural predators that specifically target the pest species, thus minimizing harm to non-target species. A disadvantage is that it can upset the balance of nature; for example, if the predator population increases excessively, it may lead to a decline in prey populations, causing further ecological imbalances.
Step 4
Would you expect a similar trend to that shown by myxomatosis as time passes? Explain your answer.
Answer
Yes, it is plausible to expect a similar trend to that shown by myxomatosis as time passes with HIV. Over time, human populations may develop some level of natural immunity or resistance to HIV, analogous to the way some rabbits became immune to myxomatosis. However, factors such as the virus's mutation rate and the availability of medical interventions could also significantly influence the outcome.
Step 5
Outline briefly how a virus replicates (reproduces).
Answer
A virus replicates by first attaching to a host cell. It then introduces its nucleic acid (either DNA or RNA) into the host cell. The host cell's machinery is then hijacked to replicate the viral genetic material and produce viral proteins. These components are assembled to form new viral particles, which are released from the host cell, often destroying it in the process.