Twins are used in variation studies because they allow researchers to isolate the effects of genetic and environmental factors. Studying twins who share genes but are raised in separate environments or together in the same environment can show whether differences between twins are due to nature or nurture. This helps researchers understand the relative contributions of genetic and environmental influences on traits.

1. why are twins used in variation studies?

2. Obesity Studies When the research linking the
variant of the FTO gene to obesity
was released, newspaper headlines
such as ‘Obesity Gene Discovered’
appeared in the media with reports
claiming that people can’t fit into
their jeans because of their genes...
Do such reports give a true
reflection of the research?
Does the so-called obesity gene
cause obesity?
Why do some researchers fear that
reports of an ‘obesity gene’ could
increase the incidence of obesity?

3. Dog Whelk
Investigation
A species commonly used in variation
studies is Nucella Lapillis, the dogwhelk.
They are large marine molluscs that live
on rocky shores. They are mainly
predators and feed on barnacles and
mussels. Their enemies include shore
crabs which crack open the shell with
their strong claws.
The easiest variation to study is related
to the shell that surrounds it. Shell
variations include size, shape, colour, size
of aperture and banding

4. Hand span
investigation