variation. Flashcards
what is variation?
differences within a species.
can either be inherited (from family), affected environmental factors or a combination of both.
define inherited characteristics.
features that are passed down from parents and are determined by DNA.
define environmental characteristics.
features that are affected by how we live and the choices we make eg: what you eat/ where you live.
define interspecific variation.
variation between species.
define intraspecific variation.
variation within species.
categorise these words into the sections: inherited, both and environmental (referring to characteristics.) hand size, blood group, foot size, eye colour, rolling tongue, hair colour, earlobe shape, sporting ability, height, reg-green colour blindness, skin colour, genetic diseases, language spoken, intelligence, body mass.
inherited: blood group, eye colour, natural hair colour, red-green colour blindness, genetic diseases.
both: sporting ability, height, skin colour, hand size, foot size, rolling tongue, earlobe shape, intelligence, body mass.
environmental: language spoken.
what two types of variation can you get?
continuous and discontinuous variation.
what is continuous variation influenced, controlled by, what kind of categories does it have, is it quantitive, what limit/ not does it have on what, what sort of graph is used to represent it?
environment, genes, quantitive, no distinct categories, no limit on the valve that can occur within a population, a line graph.
what are some examples of continuous variation?
weight, foot length, height.
what is discontinuous variation affected/ not by, what is it controlled by, is it qualitative, what kind of categories does it have?
unaffected by environment, few genes, qualitative, distinct categories.
what are some examples of discontinuous variation?
natural hair colour, ear lobes, eye colour, gender.
exam questions: sex cells are produced by meiosis, describe what happens to the chromosomes when a cell divides by meiosis?
chromosomes are replicated and arranged into pairs. they line up at the equator and divided to opposite poles of the cell and the cell divides.
exam questions: Darwin’s theory of natural selection depends on the fact that individual organisms within a species may show wide range of variation, explain how meiosis and sexual reproduction gives rise to variation?
offspring receives alleles form both parents.
gametes fuse.
exam questions: mutation may also give rise to variation, what is meant by variation?
new form of gene.
are all mutations harmful? explain the reason for your answer.
no. some are neutral. some increases your chance of survival.
