variation

[jaja]

hello
making notes from teh study design, i couldnt find info on continuous and discontinuous variation
does that simply mean genotypes can continue in a family but phenotype can't???
and for variation genotype and phenotype do we simply need to noe their definitions/???  And how do they variy////

[shinny]

hello
making notes from teh study design, i couldnt find info on continuous and discontinuous variation
does that simply mean genotypes can continue in a family but phenotype can't???
and for variation genotype and phenotype do we simply need to noe their definitions/???  And how do they variy////

•   A continuous trait is one which does not appear to have a discreet phenotype, and will tend to show a wide range of phenotypes across a population, and may often result in a normal distribution. Conversely, a discontinuous trait has discreet phenotypes.

To elaborate, an example of a continuous trait is height in a population. Most continuous traits arise because there are a number of genes which code for height, and together with environmental factors, height is said to be multifactorial as such a wide range of factors impact on its phenotype. Most continuous traits end up producing a normal distribution when you observe them in a population.

On the other hand, discontinuous traits include things like blood type which are discrete in that they can be defined clearly as either A, B, O, or AB, and then + or - for the Rhesus antigen. In this case, because a much lower number of genes code for the phenotype as well as there being no environmentally determined component, there are far fewer phenotypes available.

As for what you need to understand, well, definitions are always needed in Biology, and identifying whether a factor is continuous or discrete has been an exam question before. I also recall there being a question where you had to do something similar, but from observing a graph of a trait.