Transcript SELECTIVE BREEDING

SELECTIVE BREEDING &
GENETIC ENGINEERING
3.f. Develop a logical argument for or against
research conducted in selective breeding and
genetic engineering, including (but not limited
to) research conducted in MS.
Bellwork 1/5
► Write
a paragraph (at least 5 sentences)
about your Christmas Break
Selective Breeding & Genetic
Engineering
► Selective
breeding & genetic engineering
are 2 scientific techniques in which humans
try to produce offspring with desirable traits
What is selective breeding?
► Definition:
 Selective breeding is where
humans select (chose) 2 animals
with desired traits & breed
(mate) them trying to produce
offspring with the desired traits
of both parents
Selective Breeding
► Typically,
strains which are selectively bred
are domesticated
► Over many generations, the practice leads
to the development of strains with the
desired characteristics
Examples of selective breeding
► Intentionally
mating 2 dogs in order to
achieve or eliminate a specific trait
► A farmer saves seed from a hearty crop to
replant the next year
► Dogs are bred for competition or for hunting
► Cows can be bred to increase muscle mass
or milk production
Examples of Selective Breeding
► Dogs
are a good example of selective breeding.
Gamekeepers who hunted birds for leisure in the
1800s wanted a dog that didn’t actually exist. So,
they selectively breed a mastiff and a bulldog to
get the qualities that they wanted. Mastiffs were
big, strong & good companions, but they lacked in
speed and aggression. The bulldog however was
aggressive and fast but lacked in strength. The
selective breeding process eventually produced a
bullmastiff which was large, quick, strong, &
aggressive
Bullmastiff
Big, strong & good companion
(not aggressive or fast)
Aggressive & fast (not big & strong)
When selective breeding
these 2 dogs, we get a
Bullmastiff
Large, quick, strong & aggressive dog
Example of Selective Breeding in
Cattle
Brahman cattle: good resistance to
heat, but poor meat
English shorthorn cattle: good beef, but poor
heat resistance
When selecting to breed
these 2 animals we get a
Santa Gertrudis cattle
Result = good beef AND
resistant to heat
Selective Breeding in Crops
Selective Breeding of Lions & Tigers:
LIGER
► Ligers
are the world’s biggest cats
► Larger than their parents with the strength
of a lion and speed of a tiger combined
► An average male liger stands almost 12ft on
its hind legs & weigh up to half a ton (twice
the weight of a wild lion or tiger)
How did the liger appear?
► If
the father is a lion & the mother is a tiger,
the offspring are known as ligers and the
pairing results in gigantism
Strong but lacks speed
Fast but not
as strong
Ligers are fast & strong
& twice as big as parent
Why do people selectively breed
animals & plants?
► To
make animals grow bigger, faster,
prettier & stronger
► To make plants grow bigger, faster, prettier
& produce more crops
Pros of Selective Breeding
► Benefits:
 Farmers can produce crops with higher yield
►More
fruit or vegetables on a stalk
 Farmers can produce animals that grow more
meat, more milk, more eggs, faster & stronger
 Can produce friendlier and prettier pets
Cons of Selective Breeding
► Disadvantages:
 Loss of genes in a population
► By
not allowing some animals to breed, their genes could be lost
forever in a population
► Take Hitler for example, he tried to kill all Jews, therefore, trying to
eliminate the genes and all Jews from the planet
 Animal discomfort
► Farmers
breed cows to have large utters, so now some cows have
difficulty walking & have health problems
► Some chickens are too heavy to stand, so they have to lay down
all the time
 Can lead to inbreeding
► In
order to create a certain type of animal through selective
breeding, sometimes brothers & sisters of a population will mate to
pass on favorable traits, and this can lead to bad health problems
for children of inbreeding
Bellwork 1/6
► Define
selective breeding.
Classwork 1/6
► With
a partner, come up with at least 5
specific examples of selective breeding.
 IF YOU FINISH BEFORE I CALL TIME, YOU
NEED TO COME UP WITH MORE UNTIL I TELL
YOU TO STOP.
GENETIC ENGINEERING
► Genetic
engineering is a lot like selective
breeding but a much faster process
► Definition: taking favorable genes from one
organism and implanting it into another
organism’s DNA
 This can only be done in a laboratory with
special equipment
Examples of Genetic Engineering
1.
People have taken the insulin making gene
from humans and inserted it into bacteria
causing bacteria to make human insulin
► Why?
►
Bacteria can reproduce quickly causing them to
produce insulin at a much faster rate
Examples of Genetic Engineering
2.
People have taken bad genes (genes
which cause cancer and other diseases)
out of a person and inserted healthy genes
into a person to cure them of diseases
► However, they may be cured of that disease
but get another worse disease because of
being implanted with the other gene
Examples of Genetic Engineering
3.
People have taken a weed resistant gene
and inserted the gene into certain crop
plants
► Now farmers can spray weed killer on the
crops to kill the weeds, but the spray will not
affect the crops.
► The crops will grow better and bigger because
weeds do not take away sunlight, nutrients,
and water
►
However, this gene has leaked over into the weed
population sometimes and caused the weeds to be
resistant to herbicides (weed killer spray)
Examples of Genetic Engineering
4.
People have inserted genes into crops to
make the crops resistant (poisonous) to
pests, but are harmless to humans (we
think)
Genetically Engineered Fish
► We
have inserted genes into fish to make
them grow twice as big and twice as fast
Genetically Engineered Chickens
► We
have inserted genes into chickens to
make them grow twice as big and twice as
fast. They are so big they can’t walk.
Genetically engineered crops
► Humans
have injected genes into crops to
make them grow in colder environments
► Humans have injected genes into crops to
make them grow in dry (drought)
environments
Genetically Engineered Pigs
► Humans
inject genes into pigs’ DNA in order
for the pig to grow human-like organs, so
people can transplant these organs into
people who need them
Genetically Engineered Mice
► Humans
inject genes into mice to make the
mice grow human ears for cosmetic
purposes
Genetically Engineered Vaccines
► Genetically
engineered vaccines may be
safer because they do not use live viruses
like traditional vaccines do
Genetic Engineering
► Genetic
engineering may work wonders but
it is all a process of manipulating the natural
The Pros & Cons of
Genetic Engineering
Pros Include:
1.
2.
3.
Humans have made crops with better
taste, nutrition, and growth rate
Humans have made pest resistant crops
and crops with longer shelf life
Humans have been able to produce new
foods
► Foods which couldn’t be reproduced in nature
4.
5.
Humans can help cure certain disease
Boosts positive traits and suppress
negative ones
Cons Include:
1.
2.
3.
By making plants bigger, taste better, and better
appearance we have accidentally made some
crops allergenic to people
By making plants bigger, taste better, and better
appearance we have accidentally made some
crops have less nutritional value
Accidental gene transfer
► Such as when we inserted genes into crops to make
them resistant to pest or herbicides, the genes leaked
over into weeds and made them resistant to pest and
herbicides too
Cons Include:
4.
Genetic engineering in human beings can have
certain side effects
► While treating one defector disease, the genetic
engineering may lead to another disease which could
be worse
5.
What’s next?
► Will people try to insert genes into babies to have
children which are smarter, muscular, prettier, certain
color eyes, certain color hair, and talented
6.
Playing God…
Quiz
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8.
Define selective breeding.
List 3 examples of selective breeding.
List 2 benefits of selective breeding.
List 2 disadvantages of selective breeding.
Define genetic engineering.
List 3 examples of genetic engineering.
List 2 benefits of genetic engineering.
List 2 disadvantages of genetic
engineering.
Bellwork 1/7
► List
benefits and disadvantages of selective
breeding.
► List benefits and disadvantages of genetic
engineering.