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Long before the development of agricultural crops, hunter-gatherers in southern Africa would pick the tastiest nutty fruits of the marula tree and scatter them around their camps - VCE - SSCE Biology - Question 9 - 2010 - Paper 1
Question 9
Long before the development of agricultural crops, hunter-gatherers in southern Africa would pick the tastiest nutty fruits of the marula tree and scatter them aroun... show full transcript
Worked Solution & Example Answer:Long before the development of agricultural crops, hunter-gatherers in southern Africa would pick the tastiest nutty fruits of the marula tree and scatter them around their camps - VCE - SSCE Biology - Question 9 - 2010 - Paper 1
Step 1
a. Explain how this practice is an example of selective breeding.
Answer
This practice is an example of selective breeding as it involves humans intentionally selecting the best fruits from the marula trees, which is indicative of a desired phenotypic characteristic—specifically, the tastiness or nutritional value of the fruit. The selective agent in this scenario is humans, who choose the best fruits to propagate, ensuring that the traits associated with the selected fruits are passed on to the next generation of trees.
Step 2
b. i. What can you infer about the genotype of trees propagated through marcotting?
Answer
The genotype of trees propagated through marcotting is identical or the plants are clones. Since marcotting involves taking a branch from an existing tree, the new plants will have the same genetic makeup as the parent tree, making them genetically identical.
Step 3
b. ii. Outline one disadvantage of a plantation of marula trees grown through marcotting compared to a natural population of marula trees.
Answer
One disadvantage is the lack of genetic variability. In a plantation where all trees are clones, a disease could wipe out the entire population, as there would be no genetic diversity to provide resistance. In contrast, a natural population has a mix of genotypes, which can offer protections against various threats.
Step 4
c. Should the fruit from marcotted marula trees be labelled as genetically modified (GM)? Explain why.
Answer
The fruit from marcotted marula trees should not be labelled as genetically modified (GM). Marcotting is a natural asexual propagation method that does not involve altering the plant's DNA or genome. Therefore, the genetic structure of the fruit remains unchanged, and it does not fit the common definition of genetically modified organisms.