Artificial Selection

Multiple Choice

The process of choosing parent organisms for desired characteristics is called ________.

• natural selection

• Artificial selection

• random selection

• genetic manipulation

Artificial Selection
Selective Breeding

Objective:
• Explain how artificial selection influences the

inheritance of traits in organisms

• Explain how humans have manipulated traits

in various organisms to acquire desired traits

What is artificial selection?

Artificial Selection or “ Selective

Breeding”

• the breeding of plants and animals to

produce desirable traits

• people select certain organisms to

reproduce in order to obtain
offspring that inherit ONLY the
desired features

Dogs – bred for a purpose

• Dogs have been selectively bred for a

purpose for over 14,000 years

• How many breeds of dogs currently

exist?

• Currently there are over

400 breeds of dogs.

• All descended from the wolf.

Dogs – bred for a purpose

• Dogs have been selectively bred for a

purpose for over 14,000 years

• Starting with some wolves, dogs were

initially bred to help with:

– Hunting; producing
sight hounds, scent
hounds, terriers, and
retrievers

Dogs bred as sighthounds -
clockwise from top left: Whippet,
Borzoi, and Saluki

Observe and record the similarities
in their anatomy.

What physical characteristics do you
think were selected?

14thcentury
print of a hunt.

Can you spot
the sight-
hounds?

How did you
identify them?

Dogs – bred for a purpose
–Farming; producing
herding dogs and
guard dogs

German
Shepard

Great Dane

Dogs – bred for a purpose
Farming; producing herding dogs

Dogs bred as herding dogs – clockwise
from top left – Border collie,
Lancashire heeler, Rottweiler, Old
English Sheepdog
Do you think the
characteristics that
are bred for are
physical or
behavioural?

Why?

Dogs – bred for a purpose

• Modern breeding has given us

companion dogs and toy dogs –
whose purpose is to keep us
company.

• What characteristics would be

desirable in companion dogs?

• What characteristic common in

all toy breeds of dog?

All 400 dog breeds are the product
of artificial selection!

Let’s look at the history of where cows
came from….

Suppose you wanted a variety of cow that

produced a lot of milk. How do we get to our goal?

2. Let only these cows reproduce

4. Let only these offspring reproduce

5. Keep repeating the process of selection and
breeding until you achieve your goal.

3. Select the offspring that produce the most milk

1. Select the cows in your herd that produce the most milk

What was the “desired trait”?

• Identify the

desired trait.

• How do you

know?

Meat

Dairy

Draft

What was the “desired trait”?

• Identify the

desired trait.

• How do you

know?

Artificial

selection in

plants

Wheat

• Tall wheat plants have a high yield,

but are easily damaged in wind and
rain

• Dwarf wheat plants have a low

yield, but are able to survive nasty
weather

• Q: What do you think happened when

the two types were cross-bred?

•

Q: What do you think happened

when the two types were cross

-

bred?

•

A: A dwarf wheat

with high yield that

was able to survive

nasty weather. !

PROBLEMS

• Traits are chosen to

benefit humans

, not the

animal
– Physical problems often occur in domestic animals

eg. Inflammation of the udder (mastisis) in cows due
to increased milk production

• Usually involves

inbreeding

, which can lead to

reduced genetic diversity

• Alters “natural selection ”; Interferes with

an organisms natural ability to change
overtime in order to adapt to changing
environments

In summary…

•

Selective breeding = Artificial selection

• Has been used for animals and plants
• The method:

– The

desired characteristics

are identified

– They are

bred

together

– Only the

offspring exhibiting the desired

characteristics

are bred again

– This is

repeated over several generations

until the desired trait is fully developed

Natural vs. Artificial selection - Group sort

You can open this webpage in a new tab.

Copy link

Open in new tab

Multiple Choice

Which statement is true comparing natural selection and artificial selection?

• In natural selection, traits benefit humans and in artificial selection, the traits benefit the species

• In natural selection, traits benefit the species and in artificial selection, the traits benefit humans

• In natural and artificial selection, the process takes hundreds of years to occur

• In natural and artificial selection, nature determines what traits will be passed down to offspring.

Multiple Choice

Artificial selection is also known as _________.

• natural selection

• selective hearing

• genetic manipulation

• selective breeding

Multiple Choice

Artificial selection is also known as

surivial of the fittest.

• True

• False

Multiple Choice

Humans often use methods of artificial selection, such as selective breeding, to produce horses with specific traits.

​

Which statement best describes how selective breeding helps horse breeders produce the most desirable traits for racing?

• Selective breeding produces horses with a higher rate of survival due to an increase in the genetic diversity of the horse offspring.

• Selective breeding helps breeders control which traits are passed on by producing horse offspring that only have the desired traits.

• Selective breeding uses two horse parents with the desired traits to increase the chances of passing the desired traits on to offspring.

• Selective breeding uses two horse parents with unknown traits to produce offspring with genetic variations and different traits.

Multiple Choice

Artificial selection takes ________.

• a shorter period of time than natural selection

• a longer period of time than natural selection

• the same amount of time as natural selection

• millions of years