VCE Biology – Natural SelectionBy Katherine Twite in VCE
8th of June 2018
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Hi, everyone – thanks for tuning in again. Today, we’re going to be talking about natural selection.
So, natural selection – it can sort of be summarised as “survival of the fittest”, which is probably a term that you’ve heard before. But today we’re going to be running through the actual process.
So essentially, when you have a population of a certain species, there will be variations in the traits in that population. So what I mean by that is that there’ll be differences in the phenotypes between individuals of that species. So for example, in a population of cows, some of those cows will be white, and some might be black or brown. There is variation in the coat colour in that population.
Now what happens is environmental selection pressures – that could be climate, that could be a disease – will act upon the phenotypes of that population so that the individuals with the traits that are more favourable are more likely to be able to cope with that pressure, and, therefore, more likely to survive than those which don’t have the favourable traits that will allow them to cope with that pressure.
This means that, over time, those with the alleles conducive to that favourable trait will increase in the populations – will have an increased frequency of that particular allele. And this means that, over time, the population will change to suit its environment, and be able to cope with those selection pressures.
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