This document contains notes and instructions for a biology lesson on genetics and heredity. It includes definitions of key genetics terms like phenotype, genotype, homozygous, heterozygous, codominance. It also describes Gregor Mendel's pioneering pea plant experiments in genetics. The document provides examples of monohybrid and dihybrid crosses using Punnett squares to determine the probabilities and ratios of traits being passed on from parents to offspring. Students are instructed to complete warm up questions, use their textbook to answer questions about Mendel, and work through genetic problem sets using Punnett squares.

1. Warm Up- Complete Monday’s warm
up question

2. 
Questions???

3. 

Problem: Are traits controlled by dominant
alleles more common than traits controlled by
recessive alleles?
Hypothesis- come up with what you think will
happen

4. Traits 1
Number
Traits 2
1
Free ear lobes
Attached ear lobes
2
Hair on fingers
No hair on fingers
3
Widow’s peak
No widow’s peak
4
Curly hair
Straight hair
5
Cleft chin
Smooth chin
6
Smile dimples
No smile dimples
7
Bitter gene
No bitter gene
8
Brown eyes
Blue eyes
Number

5. 
Use your textbook and group to answer the
questions.

6. Traits 1
Number
Traits 2
1
Free ear lobes
Attached ear lobes
2
Hair on fingers
No hair on fingers
3
Widow’s peak
No widow’s peak
4
Curly hair
Straight hair
5
Cleft chin
Smooth chin
6
Smile dimples
No smile dimples
7
Bitter gene
No bitter gene
8
Brown eyes
Blue eyes
Number

7. Traits 1
Number
Traits 2
1
Free ear lobes
Attached ear lobes
2
Hair on fingers
No hair on fingers
3
Widow’s peak
No widow’s peak
4
Curly hair
Straight hair
5
Cleft chin
Smooth chin
6
Smile dimples
No smile dimples
7
Bitter gene
No bitter gene
8
Brown eyes
Blue eyes
Number

8. Traits 1
Number
Traits 2
1
Free ear lobes
Attached ear lobes
2
Hair on fingers
No hair on fingers
3
Widow’s peak
No widow’s peak
4
Curly hair
Straight hair
5
Cleft chin
Smooth chin
6
Smile dimples
No smile dimples
7
Bitter gene
No bitter gene
8
Brown eyes
Blue eyes
Number

9. Warm UpWhich of the following statements best describes how the
four planets closest to the sun are different from the next
four planets in our solar system?
The four closest planets are more dense
b.
The four closest planets have more moons
c.
The four closest planets have greater diameter
The four closest planets take longer to complete one orbit
a.
d.

10. Warm Up
Complete Wednesdays warm up question

11. 
Heredity is the passing of physical characteristics from
parents to offspring

12. 

A trait is a different form of a characteristic
Ex.: height, eye color, hair color

13. 

The material that controls which traits are
expressed in an organism
There are two copies of each gene- one come
from the father and the other comes from the
mother.

14. 
A different form of a gene

Two alleles are inherited, one from each parent
Ex.: the gene that controls stem height in peas has one allele
for tall stems and one allele for short stems

Example= eye color, hair type


15. 
An organism’s traits are controlled by the alleles it
inherits from its parents. Some are dominant, while
others are recessive
A dominant allele is one whose trait always shows up in
the organism
 A recessive allele is hidden whenever the dominant allele
is present

 A trait controlled by a recessive allele will only show up if the
organism does not have the dominant allele

16. 
Read pages 76-78 in your text book Ch.3 Sec.1

Answer the questions about Gregor Mendel

You may work as a group

17. 


Considered the father of genetics
The first person to trace the genetics of a living thing
Became famous for his pea plant experiment
 Cross pollinated two plants with contrasting traits
 Started experiment with two purebred ( the offspring of
many generations that have the same trait) plants,
pollinated one of the plants, and waited for the
offspring to form
 In all of Mendel’s crosses, only one form of the trait
appeared in the first generation, in the second
generation, the “lost” form of the trait always
reappeared in about ¼ of the plants

18. Warm UpWork on Thursday’s Warm Up
question

19. 
Phenotype- physical appearance, visible traits

Genotype- genetic makeup, allele combinations

Homozygous- two identical alleles for a trait

Heterozygous- two different alleles for a trait

Codominance- the alleles are neither dominant nor
recessive; both alleles are expressed in the
offspring

20. 


Homozygous dominant- both traits inherited are
dominant
Homozygous recessive- both traits inherited are
recessive
Heterozygous dominant- one trait inherited is dominant
and one trait inherited is recessive

21. 


Probability is a number that describes how
likely it is that an event will occur
The laws of probability predict what is likely to
occur, not will necessarily occur
Ex.: tossing a coin

What will happen and what is the probability or
getting heads each time?

22. 



A punnet square is a chart that shows all of the
possible combinations of alleles that can result
from a genetic cross.
It shows all of the possible outcomes of a
genetic cross and to determine the probability
of a particular outcome
Helps you understand how probability applies
to genetics
The allele that each parent will pass on to its
offspring is based on probability

23. 




1. draw a box that has 4 squares
2. write the male parent’s alleles along the top
of the square, and the female parent’s alleles
along the left side.
3. copy the male parent’s alleles into the boxes
below
4. copy the female parents alleles into the boxes
to the right
5. the punnett square now shows all of the
combinations possible in the offspring

24. 
Male- Bb, Female- bb

25. 
Male- Rr, Female- Rr

26. 
Male- DD, Female- dd

27. Warm UpAnswer the question for Friday