Transcript Selective Breeding - ESC-2

Artificial Selection
or
Selective Breeding
What is
Selective Breeding?
 Selective breeding is the process of breeding
plants and animals for particular traits. The term
selective breeding is synonymous with artificial
selection.
 This selection process is "artificial" when human
preferences for specific traits have a significant
effect on the changes in a particular population
or species.
Domestication and
Selective Breeding
 Domestication is the process whereby a
population of animals or plants, through a
process of artificial selection, is changed at the
genetic level, accentuating traits desired by
humans.
 It differs from taming in that a change in the
genetics and physical traits of the animal
occurs. Taming is the process by which animals
become used to the presence of humans.
Advantages of
Selective Breeding
 Selective breeding tries to establish and
maintain certain stable traits that animals
will pass to the next generation.
 These are traits that humans find desirable
in domesticated species such as disease
resistance, strength, calmness, more lean
meat, endurance, etc.
 In many cases this makes the species
stronger.
Disadvantages of
Selective Breeding
 Breeding from too small a gene pool can lead to
the passing on of undesirable characteristics or
even a collapse of a breed population due to
what is called inbreeding depression.
 Breeding for only one trait, over all others, can
cause problems.
DOG:
bred for
pulling,
hunting, and
protection
wolf
great dane
chihuahua
greyhound
pitbull
bassett
hound
CATTLE:
Selectively
bred for
meat or milk. The auroch (ancient bovine, all modern
english breeds derived from
holstein
angus
brahma
hereford
dwarf angus
HORSE:
bred for
pulling,
riding, meat,
and milk
Prezwalski’s horse
shire
miniature
arabian
quarter horse
Tennessee
walker
CAT:
bred for pest
control and
companionshi
p
African wild cat
munchkin
Maine coon
devon rex
persian
Scottish fold
CORN: bred for larger kernel and ear
size
WILD CABBAGE: bred for food
wild cabbage
kale
brussel sprouts
cauliflower
broccoli
collard greens
Selective Breeding…gone too far???
Selective Breeding and
Natural Selection
The main difference between natural
selection and selective breeding is
human involvement.
 In natural selection, the reproduction of
organisms with certain traits is attributed
to improved survival or reproductive ability
(survival of the fittest).
 In artificial selection, humans favor specific
traits and control breeding for those traits.