differences between individuals of the same species and of different species
The different ear shapes are examples of genetic variation
The two pierced ears are examples of environment variation
(variation that happens during a lifetime will not be passed
on to any offspring)
Discontinuous variation
Discrete varieties
Red, Purple
Continuous variation
Unlimited varieties
300nm - 700nm
Why have they drawn
a LINE GRAPH?
Because all of the
data is CONTINUOUS
Continuous means it
can be any value
Angle of incidence in degrees
Why have they drawn
a BAR CHART?
Because some of the
data (material) is
CATEGORIC
DISCONTINUOUS
Discontinuous means
it can only be certain
values
How many variations can you spot?
• continuous
• discontinuous
What is the difference
between phenotypic variation
and genetic variation?
Phenotypic
variation is
caused by both
genetic and
environmental
factors
Phenotypes
determined by
genetics
Phenotypes
determined by the
environment
both
Discontinuous variation results in a limited number of phenotypes with no
intermediates. It is mostly caused by genes alone. Continuous variation results
in a range of phenotypes between two extremes.
YOU MUST HAVE:
A DATA TABLE
and A GRAPH
ENSURE THE GRAPH
AND TABLES HAVE
HEADINGS AND UNITS
The IGCSE spec requires you to conduct
research and present your findings on
continuous / discontinuous variation.
Your task is to come up with an
experiment, whereby you can see if
there is a correlation between two
factors –e.g. is shoe size linked to arm
length? You will need to collect
sufficient data/measurements, analyse
the results & plot a scatter graph. From
the graph, you should be able to
determine what kind of correlation is
present, if any; positive/negative/none.
You have the rest of the lesson to
complete this investigation, which then
must be handed in.