Download Natural and Artificial Selection

G7- I can list examples of changes in genetic traits due
to natural and manmade influences
What is Natural Selection?

Write it on your white board
Which of the following is an
example of Natural Selection?
A.
B.
C.
Humans breed cows to produce 8
gallons of milk per day
Farmers plant only the biggest, tastiest
ears of corn and as a result will get
more big, tasty ears of corn
Horses were once short and slow to
escape predators. Today they are taller
and run very quickly, making it easier to
escape predators
What is Artificial Selection?

Write it on your white board
Which of the following is an
example of Artificial Selection?
Millions of years ago, plants were short
and did not have root systems, but now
plants can grow very tall and have large
root systems
B. Over time, birds bones have become
hollow making them lighter for easy flying
C. Tomatoes at the grocery store stay fresher
longer because humans like eating fresher
tomatoes and therefore grow only fresh
tomatoes
A.
Read the following:
“Antibiotics work to kill bacteria.
Bacteria are single-cell organisms. If
bacteria make it past our immune
systems and start reproducing inside our
bodies, they cause disease. We want to
kill the bacteria to eliminate the
disease.”
Raise your hand if you have ever taken
antibiotics for anything
Read the following:
“An antibiotic is a selective poison. It has been
chosen so that it will kill the desired bacteria,
but not the cells in your body. Each different
type of antibiotic affects different bacteria in
different ways. For example, an antibiotic
might stop a bacterium's ability to turn sugar
into energy, or its ability to build its cell wall.
When this happens, the bacterium dies
instead of reproducing.”
Summarize the idea of this paragraph with your
partner
Read the following:
“Antibiotics do not work on viruses because
viruses are not alive. A bacterium is a
living, reproducing organism. A virus is just
a piece of DNA(or RNA). A virus injects its
DNA into a living cell and has that cell
reproduce more of the viral DNA. With a
virus there is nothing to "kill," so antibiotics
don't work on it”
Can Viruses (or other non-living things)
Adapt? Why do you think this?
Think about “Survival of the
fittest.”
New antibiotics always have to be created
to treat colds and flu. Why do you think
this happens?
Antibiotics
Why is it a mistake to take antibiotics for
viral cold/flu?
A. Bacteria becomes resistant
B. The virus becomes resistant
C. Antibiotics are expensive
D. Antibiotics taste bad
Peppered Moths and Adaptations

http://www.youtube.com/watch?v=LyRA
807djLc
What characteristic of moths was
“selected” to survive when the soot
turned the trees black?
Peppered Moths and Adaptations
Because the trees turned black, were
there more black peppered moths, or
white peppered moths in the next
generation? Why is this?
Farmers are always changing the
types of insecticide to fight pests
because…
A.
B.
C.
D.
Insecticides actually make insects
healthier
Chemical labs make more money by
making new insecticides
This is a tradition that farmers always
follow
Insects develop resistance to old
insecticides
Write down two examples of
adaptations that organisms have
changed because of Natural
Selection
Write down two examples of
adaptations in organisms that have
changed because of Artificial
Selection
A tangelo is a cross between a
tangerine and a grapefruit. Why do
plant Scientists make genetic
crosses like this?
The new offspring may have desirable traits
They are accidents that scientists cannot
prevent from happening
C. Tangelos are better than tangerines or
grapefruit
D. We need to keep discovering new fruits
because the fruits we have are not healthy
enough
A.
B.
Human beings walk upright.
What adaptive advantage does
this provide?
We run faster than other animals
B. We see in more color than other
animals
C. It allows us to use our hands
D. It gives us the ability to hear better
A.
*Is this adaptation a result of Natural
Selection or Artificial Selection?
Asexual v. Sexual
A disastrous infection has the capability to
wipe out an entire group of organisms, but
some organisms may survive if they have
the right traits for survival.
Does an Asexual population have a better or
worse chance of surviving the disastrous
infection than a Sexual population?
Discuss what you think with a partner and
write it on your whiteboard