Pavia National High School

Science Department
Department of Education

Lesson Plan
GRADE 9 SCIENCE
HEREDITY: INHERITANCE AND VARIATION
I. Objectives
At the end of the class discussion, the Grade 9 learners must have:
 Defined Incomplete dominance
 Differentiated Codominance from Incomplete Dominance
 Performed an activity that demonstrates codominanace of traits
II. Learning Content
A. Subject Matter
 Heredity:Inheritance and Variation - Codominance
B. Content Outline
 Review Incomplete dominance
 What is codominance?
 Example of codominance
 Crossing of traits in Codominance using a Punnett square
 Differentiate between codominance and incomplete dominance
C. Science Concept
 Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not
completely dominant over the other allele. This results in a third phenotype in which the expressed physical
trait is a combination of the dominant and recessive phenotypes. An example in which Incomplete
dominance can be observed is in four o’clock flower plant.
 Codominance is when both alleles are expressed equally in the phenotype of the heterozygote.
 An excellent example in which codominance is evident is the Roan cow
 A cross involving a red bull and a white cow produces a roan cow having both the red and white hairs.
D. Science Process Skills
 Observing
 Analyzing
 Communicating
E. Value Focus
 Participates in class discussion
 Cooperates during group works
 Appreciates the different forms of organisms having different traits.
III. Instructional Materials
A. Visual Aids
 Printed images,
 Key Concepts written in Manila paper
 Blank Punnett squares in cartolina
B. References
 Science 9 Learner’s Module, Module 2 pp. 5-8
 Science 9 Teacher’s Guide, pp. 22-23
 Pavia National High School
Science Department
Department of Education

IV. Lesson Development

Teacher’s Activity Student’s Activity Teacher’s Remarks/Notes

“Good morning class. Please stand, let us pray” The students will stand in
attention to pray.

“Last meeting, we’ve discussed about “Incomplete dominance is a One student will volunteer to
Incomplete dominance. Who can tell what is form of intermediate recite.
incomplete dominance?” inheritance in which one allele
for a specific trait is not
completely dominant over the
other allele. This results in a
third phenotype in which the
expressed physical trait is a
combination of the dominant
and recessive phenotypes.”

“Give me some example in which incomplete “the four o’clock flower Other students may give their
dominance is evident.” Ma’am” own examples.
“Very good”
Engagement
15 mins
“In four o’clock flower, the red and the white is
crossed and it produces an offspring which is
color pink. The color pink four o’clock flower is
the third phenotype produced in incomplete
dominance.”

“And now, I have here a white cow and a red “No Ma’am.” The teacher will show a picture
bull. If I cross the white cow with the red bull, The students may express their of a white cow and red bull and
could they produce a pink cow??” opinions regarding the given afterwards, the graphic picture
example. of a pink cow.

“Yes, we can’t have a pink cow but instead we The teacher will present a
can have a roan cow.” picture of a roan cow.

“A roan cow has a red hair and white blotches.” The teacher will describe the
“And this another pattern of inheritance which is appearance of a roan cow.
the codominance.”

The teacher will read the

“Today, I’m going to tell you a story” “Yes Ma’am” problem stated in Activity 2:
“Are you ready to listen?” Mystery Bull

“Mang Marcelino owns purebred red cows. In

his farm he noticed that after a typhoon several
months ago, all of the fences that separate his
cattle from his neighbor’s cattle were destroyed.
During the time that the fences were down, three
bulls, one from each neighbor, mingled with his
Exploration cows. For a while, he thought that none of the
20 mins bulls found his cows, but over the months , he
noticed that all of his cows are pregnant. He
suspected that one of the bulls is the father.
Which bull is it? Help Mang Marcelino look for
the father by solving the given problem in your
activity sheets.”

“You have to determine the possible traits of the The students will individually
calves, illustrate your answers using a punnet do the Activity 2: Mystery Bull
square and answer the guide question.” in Science 9 Learner’s Module

Explanation
15 mins “Based on my example earlier, how can you “It is when both the phenotype A student will volunteer.
define codominance?” of the parents is seen in the
 Pavia National High School
Science Department
Department of Education

phenotype of their offspring.

“Very well said.” The activity will be checked
during the discussion.
“Codominance is when both alleles are
expressed equally in the phenotype of the
heterozygote.”

“in your activity, were you able to trace the “Yes Ma’am”
father of the calves? One check for the correct
answer.

“What are the possible phenotypes of the calves “All red calves” One check for the correct
in cross you made in letter A: red (RR) bull is answer.
mated with the red (RR) cow?”
One check for the correct
“what is the phenotypic percentage of the “100%” answer.
offspring?”

“Very good.” One check for the correct

“Each box for the offspring in the punnett square answer.
is equal to 25%.”
“Since it’s all red calves, you will have a 100% One check for the correct
red calves” answer.

“Understood?” “Yes Ma’am”

One check for the correct
“Next is we will cross the Red (RR) bull with answer.
the white “WW” cow and will produce all RW
offsprings”

“RW here is not pink.”

“Since this is another pattern of inheritance

which is the Codomonance, the resulting
heterozygote should express equally both the
phenotype of the parents.”

“So, the phenotype of RW in this problem is a “Roan Ma’am”

what?”

“And so, what are the possible phenotypes of the “All roan calves”
calves in cross you made in letter B: red (RR)
bull is mated with the white (WW) cow?”

“what is the phenotypic percentage of the “100%”

offspring?”

“Very good.”

“What are the possible phenotypes of the calves “Red and raon calves”
in cross you made in letter C: roan (RW) bull is
mated with the red (RR) cow?”

“what is the phenotypic percentage of the “50% red calves and 50% roan
offspring?” calves” A student will volunteer to
answer.
“Very good”

“Since you were able to identify the inheritance “In incomplete dominance and
in incomplete dominance and in codominance, codominance, the heterozygote
can you compare and contrast this two patterns inherit both the alleles from
from each other?” each of its parent. For example
is the allele for red from the
mother and the allele for white
from the father are both
present in the genotype of the
offspring.”

“But in incomplete dominance,

the two phenotypes blend in
the heterozygote resulting to a
 Pavia National High School
Science Department
Department of Education

third phenotype while in

codominance, the two
phenotypes combine but one The student will give their
penotype occupies space classmate 5 claps.
independently from the other.”
“Very well said.”
“Please give 5 claps to your classmate.”

“For you, what is the importance of studying “It is important because we

these patterns of inheritance?” can use it in producing
different breeds of animals.”
“Very good.”
“The animal breeders can cross breed animals in
Elaboration order for them to get the desired trait that will
5 mins help improve livestock in terms of meat quality
and milk production.”

“Is it only possible to animals?” We can cross breed plants too

in order to improve
production.
“Very good.”
“Get one half sheet of paper and answer the The teacher will administer a
following questions” quiz to assess students’ learning.

1. Define incomplete dominance. Answer key:

2. Define codominance 1. Incomplete dominance is a
3. Give one example for incomplete dominance form of intermediate inheritance
4. Give one example for codominance in which one allele for a specific
5. Give one example for the importance of trait is not completely dominant
incomplete dominance and codominance over the other allele. This results
in a third phenotype in which
Identify what pattern of inheritance governs the the expressed physical trait is a
following examples: combination of the dominant
1. A curly hair woman married to a straight hair and recessive phenotypes.
Evaluation man. Their daughter has a wavy hair. 2. “Codominance is when both
5 mins 2. A kitten has a color blue iris on its right eye alleles are expressed equally in
and brown iris in its left eye. the phenotype of the
3. A white dog mated with a black dog. They heterozygote.”
produces a brown puppy. 3. Pink Four o’clock flower
4. A white chicken was crossed with a black 4. Roan cow
chicken. A speckled chicken having white and 5. Use for animal breeding in
black patches is produced. order to improve livestock.
5. A white snapdragon was crossed with a red
snapdragon. Produces a pink snapdragon. 1. Incomplete dominance
2. Codominance
3. Incomplete dominance
4. Codominance
5. Incomplete dominance

Prepared by:
Louise Meara Severo

Noted by:

Mrs. Kriemehilda Gajo