Name____________________________                Homeroom___________

Observing Human Traits Activity

 

Background information:

Humans display a variety of traits that are controlled by a number of different genes.  For example, PTC testing is a method used to test for a genetic trait. People who are dominant taste PTC (phenylthiocarbamide), and people who are recessive do not taste PTC. This trait is passed genetically from parents to their children, so that if a person has the trait, then at least one of their parents had the trait as well.

In this activity you will examine some easily observable traits in yourself and your classmates.  You will record your observations in the data table provided.

 

Purpose: What are some patterns of human heredity?  Are all dominant traits the most common in humans?

 

Data Table -

Trait

Do you possess it?

# in class who possess

% who possess it.

# Counted x 100

   Total #

Do you think it is dominant?

Is it dominant?

Tongue rolling

 

 

 

 

 

Widow’s peak

 

 

 

 

 

Free lobes

 

 

 

 

 

Dimples

 

 

 

 

 

Freckles

 

 

 

 

 

Left handed

 

 

 

 

 

Blue Eyes

 

 

 

 

 

Simian ply

 

 

 

 

 

Mid-Digit hair

 

 

 

 

 

Red hair

 

 

 

 

 

Flex fingertips

 

 

 

 

 

Dimple in middle of chin

 

 

 

 

 

PTC taste

 

 

 

 

 

Graph – Decide how to graph the information above and use graph paper, or Spread Sheets  in order to do this.

(Insert Google Graph here or turn in hand drawn graph to substitute. BE SURE TO TAKE PHOTO FIRST)

Conclusion Questions:

1. Draw a Punnett Square for two heterozygous parents (pick any trait from about).

Trait ______________________  

2. What genotypes of children are possible?

3. What is the ratio of genotypes?

4. What phenotypes of children are possible?

5. What is the ratio of phenotypes?

Conclusion: Make a claim (that answers the above questions) and support it with evidence (from your data) and provide scientific reasoning.