Transcript PowerPoint: Artificial Selection

Artificial Selection
Mr. Carter & Ms. Dignan’s Biology Class
4 Observations that lead to
Darwin’s Theory of Evolution
Organisms can produce more offspring than
they can support.
2. Any environment has a finite supply of
resources.
3. Individuals have natural variation in their traits,
due to mutations and genetic recombination.
4. Those individuals most suited to their
environment tend to survive and pass on their
traits.
1.
4. Those individuals most suited to their
environment tend to survive and pass on their
traits.
Most of the time, the
natural environment
will determine which
traits are beneficial
and get passed on to
future generations.
 This is called natural

selection
Sometimes humans
breed organisms, and
consciously choose
which traits get
passed on to future
generations.
 This is called artificial

selection
Examples of Artificial Selection
Most of the crops that
humans consume today
have been selectively
bred for thousands of
years.
 Most of these crops look
very different from their
wild ancestors.
 Examples are rice, corn,
wheat, chickens, cows,
pigs, squash, & bananas

Basic Process of Artificial Selection
Sometimes humans selectively breed the same
plant in different ways.
 The wild mustard plant has been selectively bred
for different traits, resulting in many different
crops that humans can eat.

What traits might humans want to artificially
select for in plant and animal species?
•Volume
of food production
•Quality of food production
•Ease of food production
•Cultural “attractiveness”
•Ability to produce in different climates
•Ability to perform specific tasks – transportation,
field work, protection, etc
https://www.youtube.com/watch?
v=IDN-QeVhQTc
Artificial Selection of Dogs
Domestic dogs
were selectively
bred from
wolves.
 They were bred
for protection
and
companionship,
not food.

Issues with Artificial Selection
Is it humane?
 Loss of genetic
variation

Natural Selection vs. Artificial
Selection
Natural Selection:



Driven by natural factors
such as predators,
weather conditions, and
access to resources.
Exists within diverse
populations
Large changes usually
take many generations.
Artificial Selection:



Consciously driven by
humans.
Exists within non-diverse
populations
Large changes can occur
over a few generations