Basics of Natural Selection

Basics of Natural Selection

Model 1

We take a swab and wipe a desktop. It is allowed to grow in a medium over night. It is then split into two separate containers for another night.

Multiple Choice

What do the circles in the test tube represent?

• proteins

• E. Coli cells

• dust

• antibiotics

Multiple Choice

How many genetic variants of E.coli were present in the culture from the initial swab?

• 2

• 3

• 4

• 5

Multiple Choice

What is triclosan?

• a type of E. Coli

• a chemical that kills cells

• a virus

Multiple Choice

What variants of E.coli are found on the dish grown without triclosan?

• P

• P and Q

• P, Q and R

• P, Q, R and S

Multiple Choice

What variants of E.coli are found on the dish grown with triclosan?

• P, Q, R and S

• P and Q

• R

• S

Open Ended

What likely happened to the other variants of E.coli on the dish with the medium containing triclosan?

Multiple Choice

Suppose the desktop swabbed earlier was cleaned with a solution containing triclosan. Would living E.coli remain?

• Yes

• No

Multiple Choice

Suppose the desktop was swabbed again after cleaning it with triclosan over a 9-month school year. When the sample was cultured only variant S was seen. Is it likely that the bacteria in the new swab were on the desk 9-months ago, or are they off-spring of the original bacteria?

• The swab would have only the original bacteria on it

• The swab would have the offspring of the original bacterial one

Open Ended

What questions do you have? (I can see your name, but I will not say your name. I will just answer.)

Real Example from Great Britain

Populations of most living organisms exhibit genetic diversity among individuals. Certain traits in a population give some organisms a greater chance of survival than individuals that lack these traits. Because these traits tend to increase the chance of survival, these individuals may produce more offspring that will also have the trait that favors survival.

Multiple Choice

Which moth color was more prevalent before 1850?

• light

• dark

Multiple Choice

Describe the change in the percentage of light-colored moths between1850 and 1900

• decreased

• increased

Multiple Choice

During the Industrial Revolution through the mid-20th century, factories and power plants, which burned coal, produced large quantities of soot and smog. Near industrialized areas, black powder covered surfaces, including the moth habitat. Which color moth would have a better chance of surviving predation (better camouflage to hide from predators) on this dark surface?

• light

• dark

Open Ended

How does the coal burning help explain the change in the colors of the moth population shown?

Open Ended

Clean Air Acts were passed by governments of industrialized nations beginning in the mid-1950s. Use this information to explain why the color of the moth population shifted again.

Open Ended

Students like to say "The coal turned the moths dark." Correct this statement.