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selective breeding is also known as
artificial selection it is a process by
which humans breed plants and animals
for particular genetic
characteristics we have been doing this
for thousands of years ever since we
first bred food crops from wild plants
and started domesticating animals about
10,000 years ago this is when we made
the transition from hunter gatherers to
Farmers we no longer needed to wander
around to gather Food Supplies Wheat
barley lentils peas rice and potatoes
were all cultivated by early citizens we
also began to tame animals for milk meat
and hides goats sheep and chicken are
thought to have been the first animals
to be domesticated followed later by
bigger animals like horses and oxen for
plowing and
transportation agriculture allowed fewer
people to provide more food regular
predictable food production led to
increased populations and density of
people people now had the time to travel
trade and communicate settlements began
growing the first Villages and then
cities were built near fields of
domestic icated plants civilization was
founded upon selective breeding how does
selective breeding work parents with the
desired characteristics are selected
from a mixed population and are bred
together from The Offspring those with
the desired characteristics are then
also bred together this continues over
many generations until all The Offspring
show the desired characteristic just
think of all the breeds of dog that are
around today these were all selectively
bred from a common wolf ancestor the
desired characteristics that we select
for can be chosen for usefulness or
appearance such as insect and disease
resistance in food crops by breeding
from the naturally resistant individuals
to increase
yields animals which produce more meat
or milk to increase
yields domestic dogs with a gentle
nature large or unusual flowers
we just keep breathing and selecting and
breathing once more until we hit the
desired
jackpot look at what we've done to
Modern chickens in 50 years it's over
four times bigger due to selective
breeding by inbreeding parents that are
genetically closely related negative
outcomes can arise The Offspring will
all share very similar genes which could
make some diseases more dangerous as all
individuals would have the same weak
weaknesses the reduced gene pool also
means that they are more vulnerable as
they have less chance of being able to
adapt to changes in the environment such
as climate change there's also an
increased risk of genetic disease caused
by recessive genes being genetically
very similar if both parents carry the
recessive gene for a genetic disease
like cystic fibrosis then The Offspring
will all inherit this
disease the white tiger is a good
example of severe mutations boarding up
due to the inbreeding of individuals
that are too closely related we have
been selectively breeding for thousands
of years getting closer to our desired
goal with each generation of Offspring
nowadays we have come up with a faster
way to do it genetic engineering we can
transplant the gene for a desired
characteristic straight into an organism
we will look at genetic engineering in
more detail in another video so there
you have selective
breeding we have been doing it since the
origins of Agriculture and aren't
looking to stop anytime soon we do
however need to bear in mind the
potentially negative outcomes such as a
loss of genetic variety potentially
making the species vulnerable to other
diseases