Interactive Video Script Template
Lesson
Objective
Course
Semester
Unit
Lesson
Science 8
A
4
7
Students will complete monohybrid and dihybrid genetic crosses.
CLIP A
Introduction – 45 to 60 seconds
Visual
Audio
<Image>
Did you know that you can predict the
appearance and traits of babies if you
know the genetic make-up of the parents?
http://pixabay.com/en/family-cat-siamesecat-mother-408842/
<image>
http://commons.wikimedia.org/wiki/File:Gre
Gregor Mendel, a 19th century monk,
devoted his life to studying the genetics of
pea plants.
gor_Mendel.png
http://pixabay.com/en/spring-peafabaceae-pea-plant-6901/
<image>
His work with his pea plants would soon
earn him the nickname, the father of
genetics.
http://pixabay.com/en/pea-pod-pea-peaplant-grow-382297/
<image>
Mendel focused on breeding his peas for
specific traits.
http://morguefile.com/archive/#/?q=pea%2
0plant&sort=pop&photo_lib=morgueFile
<image>
In order to study these traits, he designed
Punnett squares.
http://commons.wikimedia.org/wiki/File:Pun
nett_square_mendel_flowers.svg
<image>
These squares allow us to organize the
traits and complete what we call genetic
crosses.
http://commons.wikimedia.org/wiki/File:DN
A_Helix_CPK.jpg
<image>
Crosses can be done several ways,
similar to the way you work out a math
problem.
http://en.wikipedia.org/wiki/File:Genetictesti
ng.png
<image>
When we examine only one trait, we call
that a monohybrid cross.
http://commons.wikimedia.org/wiki/File:Pun
nett_miguelferig.png
<image>
When we examine two traits, we call it a
dihybrid cross.
http://pixabay.com/en/guinea-pig-femaletwo-guinea-pigs-444012/
Question for Clip A
Stem: How many traits can be examined in
a dihybrid cross?
Answers for Question A
A. One
B. Two
C. Three
D. Four
Correct Response  B
Correct – Go to Clip B
Incorrect – Go to Clip E
CLIP B
<image>
http://pixabay.com/en/dolphin-marinescientists-67527/
Build on Introduction – 25 to 35 seconds
In order to study genes, scientists
manipulate organisms and their breeding
patterns.
Let’s take roses for example. Scientists
are able to identify the traits in the parent
rose generation, so they can predict the
characteristics of the offspring.
<image>
http://morguefile.com/archive/#/?q=roses&
sort=pop&photo_lib=morgueFile
<image>
Remember, when scientists simply
visually observe an organism, they can
only determine the phenotype, or the way
the organism looks.
http://morguefile.com/archive/#/?q=roses&
sort=pop&photo_lib=morgueFile
<image-rotate
as shown.>
http://pixabay.com/en/microbiology-dnapeople-structure-163521/
Question for Clip B
Stem: Which of the following best
describes an organism’s phenotype?
Answers for Question B
A. An organism’s genetic make-up
B. An organism’s observable traits
Scientists complete genetic crosses so
that the genotype can also be identified.
The genotype is the internal makeup of
the cell and organism.
C. An organism’s kinetic energy
D. An organism’s breeding pattern
Correct Response  B
Correct – Go to Clip C
Incorrect – Go to Clip F
CLIP C
Build on Clip B – 25 to 35 seconds
Visual
Audio
<image>
When scientists want to study only one
trait, such as kernel color, they conduct a
monohybrid cross.
http://pixabay.com/en/corn-corn-on-thecob-harvest-63061/
<image>
Let’s take flower color as an example.
http://pixabay.com/en/lily-flower-colorfulcolor-bright-376349/
<image>
http://pixabay.com/en/tulip-natural-flowers-
When scientists want to study two traits
on the same organism, they conduct a
dihybrid cross.
spring-japan-115036/
<image>
For example, a scientist may want to
study stem height and flower color.
http://pixabay.com/en/tulip-yellow-yellowtumor-tulips-47401/
Question for Clip C
Stem: How many traits can be examined in
a monohybrid cross?
Answers for Question C
A. One
B. Two
C. Three
D. Four
Correct Response  A
Correct – Go to Clip D
Incorrect – Go to Clip G
CLIP D
Build on Clip C – 25 to 35 seconds
Visual
Audio
<image>
http://pixabay.com/en/beautiful-close-upeye-eyebrows-2314/
When genetic crosses are conducted, the
phenotype (feen-oh-type) and genotype
(jean-oh-type) of the parents is considered
when predicting the characteristics of the
offspring.
<show images side by side with captions>
<image>
Homozygous recessive
Phenotype: Blue
Genotype: rr
If a parent is homozygous (home-oh-zyegus) for a trait, that means that they have
either two dominant alleles (uh-leel s) or
two recessive (rih-sess-iv) alleles for that
trait.
http://pixabay.com/en/contact-lens-eyelens-blue-girl-548158/
<image>
Homozygous Dominant
Phenotype: Brown
Genotype: RR
<show image with caption>
<image-text>
Heterzygous
Phenotype: Brown
Genotype: Rr
If a parent is heterozygous (het-er-oh-zyegus) for a trait, that means that they have
one dominant allele and one recessive
allele.
<Image>
<Show a “R” next to a “r” and underneath
the R show “Dominant” and underneath the
r show “Recessive”>
Remember that the dominant traits are
represented by a capital letter, and a
lower case letter represents recessive
traits.
Question for Clip D
Stem: Which of the following answers best
describes a homozygous, dominant
genotype?
Answers for Question D
A. HH
B. Hh
C. hh
D. hH
Correct Response  A
Correct - Success Alert
Incorrect – Go to Clip H
CLIP E
Remediation for Clip A – 25 to 35 seconds
Visual
Audio
<image>
http://commons.wikimedia.org/wiki/File:Gre
gor_Mendel_Monk.jpg
The father of genetics, Gregor Mendel,
spent most of his life studying the genetics
of pea plants.
<image>
His studies on pea plants provided us with
discoveries that would allow us to
organize and conduct many further and
more complex genetic crosses.
http://commons.wikimedia.org/wiki/File:PS
M_V85_D431_Results_of_crossing_two_di
fferent_races_of_white_peas.png
<image>
Punnett squares are used to help us
organize parental traits and predict the
traits of offspring.
http://commons.wikimedia.org/wiki/File:Pun
nett_square_%28PSF%29.png
<image>
There are various types of Punnett
squares that allow you to test one or more
traits.
http://commons.wikimedia.org/wiki/File:Dih
ybrid_cross.png
Question for Clip E
Stem:
Which of the following answers best
describes what can be predicted by a
Punnett square?
Answers for Question E
A. Traits of the parents
B. Traits of the grandparents
C. Traits of the grandchildren
D. Traits of the offspring
Correct Response  D
Correct – Go to Clip B
Incorrect – Go to Clip F
<image>
CLIP F
Remediation for Clip B – 25 to 35 seconds
Visual
Audio
While studying organisms, scientists will
make multiple observations.
http://pixabay.com/en/binoculars-childmagnification-100590/
<image>
The observable traits of an organism can
be described as its phenotype.
http://pixabay.com/en/bird-creamy-orangeunder-observation-607261/
<image>
The DNA, or genetic make-up of an
organism can be described as its
genotype, and often requires further
testing.
http://pixabay.com/en/blood-vial-analysislaboratory-20745/
<Show images side by side with caption>
<image>
Genotype
http://pixabay.com/en/dna-biologymedicine-gene-163466/
<image>
Phenotype
When we use a Punnett square, we can
predict both the phenotype and genotype
of the offspring.
http://pixabay.com/en/robin-lake-shorenature-bird-84616/
Question for Clip F
Stem:
Which of the following best describes an
organism’s genotype?
Answers for Question F
A. An organism’s genetic make-up
B. An organism’s observable traits
C. An organism’s kinetic energy
D. An organism’s breeding pattern
Correct Response A
Correct – Go to Clip C
Incorrect – Intervention Alert – then Clip B
CLIP G
Remediation for Clip C – 25 to 35 seconds
Visual
Audio
<image>
http://pixabay.com/en/cat-animal-cute-pet-
Let’s look at fur color of a cat for a
moment.
feline-kitty-618470/
<image>
Fur color, is only one trait, and when
scientists study only one trait, they
conduct a monohybrid (mawn-oh-hiebrid) cross.
http://pixabay.com/en/cat-female-headportrait-fur-pet-445113/
<image>
Now, the scientist wants to look at ear
shape along with fur color.
http://pixabay.com/en/cat-brown-earslisten-to-listen-408789/
<image>
http://pixabay.com/en/cat-stare-roofanimal-ear-eye-618573/
Since there are two traits, the scientist
would have to conduct a dihybrid cross.
http://commons.wikimedia.org/wiki/File:Dih
ybrid_cross.png
Question for Clip G
Stem:
If a scientist wants to study both eye color
and nose shape, which of the following
crosses would they conduct?
Answers for Question G
A. Monohybrid Cross
B. Test Cross
C. Dihybrid Cross
D. Incomplete Dominance
Correct Response  C
Correct – Go to Clip D
Incorrect – Go to Clip F
<image>
CLIP H
Remediation for Clip H – 25 to 35 seconds
Visual
Audio
When conducting genetic crosses,
regardless of how many traits you are
testing, offspring characteristics can
always be predicted.
http://pixabay.com/en/family-pier-manwoman-children-591579/
<image>
We use the terms homozygous and
heterozygous to define the characteristics
of the traits.
http://pixabay.com/en/boys-brothers-familychild-cute-554375/
<image>
If an organism is homozygous for a trait, it
is either purely dominant or recessive for
that trait.
http://pixabay.com/en/eyes-girl-blonde444156/
<image>
If an organism is heterozygous for a trait,
it has one dominant allele, and one
recessive allele.
http://pixabay.com/en/beautiful-facefemale-girl-happy-19075/
Question for Clip H
Stem: Which of the following answers best
describes the allele make-up of a
heterozygote organism?
Answers for Question H
A. Two dominant alleles
B. Two recessive alleles
C. One dominant allele and one recessive
allele
D. One dominant allele
Correct Response  C
Correct – Success Alert
Incorrect – Go to Clip G