Unit 5: Exercise 4A Inherited Traits - A Genetic Coin Toss?

Hey Everyone, Welcome back to Biology in a Box.

Today, we're going to be learning about inherited traits.

Do you have freckles?

Whether or not you have freckles, as well as many other traits you possess are the results

of dominant and recessive alleles.

Dominant and recessive alleles are different forms of the same gene.

These alleles are inherited from your parents and determined before you were born.

A dominant allele is one that is always seen if, at least one copy of it is present.

And a recessive allele is one whose trait is only observed if, a child gets two copies

of the recessive allele, one from each parent.

If, a child gets the dominant allele from one parent and a recessive allele from the

other parent, the trait that is coded by the dominant allele masks the trait coded by the

recessive allele.

For example, freckles are the result of a dominant allele.

While a lack of freckles, is a recessive trait, which is two recessive alleles.

Many traits that humans possess are inherited.

So, how likely is it that a person will end up with a certain trait?

Today, in, today's exercise, find a partner to work with.

You and your partner will be tossing two coins at a time onto a flat surface.

And recording how they land.

You will need to make a table, so you can show tally marks in the correct column to

indicate, how the coins landed for each toss.

The table should look something like this.

I flipped heads.

And let's say that my partner flipped tails.

For this toss, a tally mark would go in the heads-tails column.

When you have finished tossing the coins and recording the results a total of fifty times,

find the total number of tallies for each column.

The three totals should have a sum of fifty.

Then, find the percentage of each combination of tosses.

For example, if, fourteen out of the fifty tosses were heads-heads, to find the percentage

divide fourteen by fifty and you'll get zero point two eight.

Then multiply that by one hundred and that gets twenty-eight.

This means that twenty-eight percent of the total tosses were heads-heads.

Do the same for each total number of tosses for each of the three possible combinations.

Once you have your three percentages, double-check your answers by adding them all up together.

The sum of those percentages should equal one hundred to represent the whole set of


How do your percentages for the different combinations compare?

Do the three percentages vary much in size?

How do your percentages compare to the other groups' percentages?

Are they similar?

Thank you for watching and learning with Biology in a Box!