Download SDAIE COMMENTARY Two block lessons on genetics adapted for a

SDAIE
COMMENTARY
Two block lessons on genetics
adapted for a sheltered English class
Kyle Thompson
EDSS 446
10 December 2009
Kyle Thompson
SDAIE COMMENTARY
EDSS 446
10 December 2009
For my SDAIE segment, I have written two detailed lesson plan scripts to follow.
The lessons are an introduction to genetics, which is a complicated and
vocabulary heavy unit for both English speakers as well as ELL.
INTO:
Activation and building upon student’s background knowledge:
Students may have experience working with plants in a garden or on a farm.
Lesson #1 asks students to relate to their experience with growing plants.
Perhaps class can also have a pea-plant growing project either before or during
the genetics unit, although this is not included in the specific lesson plan for
the days included. Students are also asked to make predictions during lecture
based on their previous experiences with gardening.
Development of content-based vocabulary:
Teacher will distribute vocabulary sheets [see Sheet A and D] to support
students identifying and recording correct vocabulary definitions. Much review
of previously learned and relevant vocabulary will also be stressed if students
have trouble remembering previous content from earlier units which would help
understanding of new material and vocabulary. Also, when possible, words are
broken down into smaller forms when possible to increase vocabulary
accessibility [ex. hetero- different, -zygous, referring to zygote]. Concept Map
connects new vocabulary.
Student assumptions in relation to content concepts:
Students will begin introduction to genetics with the “K-W” portion of K-W-L
strategy. This will alert teacher to students’ previous knowledge and
background to the material, which can aid teacher later to refer to it during
the lesson. It also alerts to teacher to what misconceptions students might
have about the content, and this helps the teacher know to address those as
the material progresses.
THROUGH:
Specific strategies used to support learning:
From the “ELL Classroom Strategies” handout, there are many strategies utilized
in this two-block lesson segment. Students are asked to predict what will
happen, over and over again, when two living things are crossed. Prediction
has the students stop and think how to apply the knowledge they have
previously or recently acquired in lecture. The teacher is also constantly
monitoring student learning through the lecture and recitation by asking
questions. Also, later, the students work cooperatively in pairs on genetics
activity, which is peer-to-peer learning and teaching, but also allows teacher to
walk around the room to specifically monitor student learning and help
individual students who are having trouble. Another strategy used is imagery,
as there are several slides and whiteboard examples which exhibit images
relevant to the topic and give a visual introduction to the types of symbols
which are used in genetics. The students are taking notes on their Vocabulary
Note-Sheets, which contain the important words but asks students to use their
own words and drawings to define the words.
Opportunities for students to work in the language of their choice:
Both on the homework, Note-Sheets, and the quiz, students are given the
opportunity to work in the language of their choice. Since my school setting
SDAIE classes are 100% Latino, I also translated the directions and questions
on these various assignments into Spanish, when possible.
Ways to deepen students understanding of content concepts:
Students are given oral description, imagery, concept maps, vocabulary
definitions, partner activities, as well as a kinesthetic demonstration (in Lesson
#2) as ways to deepen (and repeat) important content. Students are also
challenged on a homework question to use a higher-level Bloom’s taxonomy
question to analyze the content they received and use new information from
the textbook to explain the logic behind Gregor Mendel’s pea-plant experiments.
Ways of grouping for instruction to provide interaction:
Students are given a 20-30 minute partner activity worksheet to complete. I
would make sure to partner the lower ELL with a higher ELL in order to provide
support for the lower student. I would also make sure to assign partners,
mixing genders as well, since students tend to self-segregate.
Types of active participation:
Students are continually given the opportunity during lecture to answer
questions posed to the class. In order to assure sufficient wait time for all
students to participate, I would make sure to enforce hand-raising as the
procedure for speaking during lecture. In Lesson #2, brave students volunteer
for front-of-class kinesthetic demonstration of meiosis and gamete formation.
Ways of modifying teacher-talk:
The concepts and definitions for genetics are extremely confusing for all
students. This is why I created the concept map to help students see how all
of the terms are connected. In addition, I would make sure to go slowly when
presenting these new terms, breaking them down when possible. I also might
be able to use a bit of my Spanish to explain their definitions in both
languages. The use of the slides as visual aids will also put pictures to the
words.
How will you facilitate students’ communication of their understanding in ways
that are less demanding linguistically:
Both on the homework assignment, the quiz, AND the Note-Sheets, students are
asked to draw. The main point-heavy question on the quiz involves drawing
diagrams instead of using words.
The feedback students will receive:
Students will receive comments and/or corrections to their diagrams on
homework and quiz by the teacher, and when possible or if applicable in
Spanish as well. Students will also receive verbal encouragement during class
and gratitude for their participation.
BEYOND:
How students will analyze and synthesize the information presented:
Students will be given “guided practice” during Lesson #1, in which they are
assisted by teacher to synthesize new combinations of alleles of traits of pea
plants on an diagram. For homework, students are asked to analyze the
conditions of Mendel’s experiment. They are also asked to come up with their
own hypothetical example, which allows students to creatively apply their new
knowledge.
How to facilitate student communication, less linguistically demanding:
Students are given ample opportunities (as previously mentioned) to
communicate their knowledge to the teacher in pictorial form.
The ways you will recapitulate and review the material:
Students are given an assignment for homework which asks them to come up
with a new trait which might result from the mixing of two parents. On Lesson
#2, the homework will be reviewed as a class. In Lesson #1, answers to the
partner work will be presented by student volunteers so that the material is
digested and presented by the students themselves.
The feedback given:
Volunteer students during the BEYOND kinesthetic modeling of meiosis will
receive real-time feedback from both teacher and students as to their
positioning and relative accuracy of scientific representation. Students will
receive direct individualized teacher feedback on the progress of their partner
work from Lesson #1.
The next steps:
Students will take the knowledge that they have learned about the very basics
of the role of meiosis in sexual reproduction and discover greater details of the
process in the homework and the next class period, the phenomenon of
“crossing-over” and the terms “homologous” and “tetrad,” which describe
“chromosomes.”
ASSESSMENT:
Ongoing, informal assessment that occurs during lesson:
As previously mentioned, students are asked many questions during lecture for
teacher to monitor student learning. In addition, teacher is able to focus on
individual students during partner seat-work. The completion and understanding
of the homework is also a good informal assessment for the teacher to check
for understanding.
Formal assessment:
Students will take a small 10 point quiz at the end of day 2 as a somewhat
formal assessment. These small quizzes keep students on their toes, and if
used regularly, can motivate students to pay closer attention in class and do
their homework, if they know they are to be accountable for the information in
the short term (versus students who are only formally assessed once every
three weeks trying to cram the night before).
The ways in which ELL’s demonstrate understanding that are not completely
dependent on their proficiency in English:
Again, the homework assignment, the quiz, and the Note-Sheet are all designed
for students to draw their understanding of the content. In addition, students
are allowed to answer their questions and complete their homework in Spanish,
when necessary. Also, students are allowed to raise their hand to answer in
Spanish during class if they wish.
SPECIFIC INSTRUCTIONAL STATEGIES:
The culturally relevant visuals, models, realia and other materials used:
Students during kinesthetic demonstration use approachable material, which is
yarn attached by Velcro on a white card. Students are shown slides and
images which contain visuals which are easily decipherable as different kinds
and colors and shapes of plants and seeds. Example plant, peas, are food
which most students will have experienced before in their eating habits and
culture (se llaman guisantes en español). See [Slides]
Alternative texts used:
May have Spanish translation of textbook available, but I don’t have a copy of
it right now. SDAIE classes in my district are allowed a budget to purchase
these materials.
Strategies for comprehension:
- Kinesthetic movement-based modeling of meiosis, students use their bodies to
demonstrate the movement of chromosomes separating.
- Drawing-based homework assignment to engage with material using visualspatial intelligence
- K-W-L is used to assess background knowledge.
- Think-Pair-Share is used for mid-lecture student predictions.
- Cooperative learning for peer-to-peer learning
- Visual models and realia used as concrete representation of genetic process
Strategies for academic language:
- Concept map of difficult terminology
- Note-taking guide distributed so students can read new language while
learning about it, while also describing definitions in their own words.
- Teacher maintains two vocabulary boards, one with generic academic
language (ratio, symbol, offspring), as well as one for content vocabulary.
Strategies that use writing for thinking purposes:
- Quick Write for students to hypothesize why F1 generation of pea cross are
all yellow.
- Quick Write used to have students write down what they think will happen to
the tall gene if Maria and Marco mate.
- Students are asked to write to analyze the experimental design of Mendel’s
pea plant breeding.
LESSON #1: INTRODUCTION TO GENETICS: Mendel, Punnett Squares, terms
Standards: Biology/Life Sciences: Genetics
3. A multi cellular organism develops from a single zygote, and its phenotype
depends on its genotype, which is established at fertilization. As a basis for
understanding this concept:
a. Students know how to predict the probable outcome of phenotypes in
a
genetic cross from the genotypes of the parents and mode of inheritance
(autosomal or X-linked, dominant or recessive).
b. Students know the genetic basis for Mendel's laws of segregation and
independent assortment.
OBJECTIVE: Students will be introduced to genetics and Mendelian principles
of independent assortment. Students will learn and practice using new
vocabulary: gene, allele, trait, phenotype, genotype, dominant, recessive.
Students will learn how to create their own Punnett Squares as a way to
organize the principle of independent assortment in a graphical way using
Mendel’s seven traits of peas.
INTO:
(10 minutes)
BRAINSTORM: What is genetics? Ask students to volunteer what they think
genetics is and what things relate to genetics, and also what they might want to
know. Informally use the “K-W” of the K-W-L strategy in order to quickly assess
student’s prior knowledge and/or misconceptions about content.
THROUGH:
(40 minutes)
LECTURE and NOTES: GREGOR MENDEL -- Around 1865, there was an Austrian
monk named Gregor Mendel who published a research paper. He was a high
school teacher, a gardener, and a scientist who bred plants. Let’s try out one of
his experiments in plant breeding.
(On board, draw a GREEN pea and a YELLOW pea).
Let’s say we like growing and eating peas. Who here likes peas? Well, let’s say
we plant some in the garden. We have two varieties, one pea is GREEN and one
pea is YELLOW. Their color is called a trait.
(Put on bold words on “Vocabulary Board,” italic words on “Academic Board”)
Let’s say we cross-pollinate. Who knows what that might mean?
(Write cross-pollinate on “Vocabulary Board”).
It means when you take the pollen from one flower and place it on another
plant to deliberately give them two sets of parents. The male pollen from the
GREEN pea mixed with the female ovum of the FEMALE pea. We collect some of
the peas, dry them, and save them for the next year. Then we plant them, and
they grow. What color peas will I get? You have sixty seconds to chat with a
partner on what color peas you both think we’ll get.
(Allow students to confer with a partner [Think, Pair, Share])
Well, what Gregor Mendel found was that ALL of his peas were YELLOW! They
did not mix and become green-yellow, like we might think. What might this
mean? Everyone do a 1-minute Quick Write and hypothesize what this might
mean, to have all of his peas turn out YELLOW and not some mixture of GREEN
and YELLOW.
(Wait time, meanwhile pass out Vocabulary Note-Sheet [Sheet A] while)
Well, let’s see what happened next. Gregor Mendel took some of the peas which
we just bred and mixed them together again, a cross pollination between the
two new YELLOW peas. When he mixed them, what do we think he got?
(Wait time)
Well, what he got was a ratio of three YELLOW peas to one GREEN pea. How
did that happen? How did he get a GREEN pea from two YELLOW parents?
Well, what he ended up figuring out was that for each trait there must be two
contributing parts from each parent. One part is dominant and one part is
recessive. The dominant trait will take over while the recessive trait is
silenced. Let’s look at a way to see this using symbols.
(Draw Punnett Square with YY across top and yy across the bottom. Cross for 1st
generation [F1] and then cross those for 2nd generation [F2])
Each one of these letters is a symbol which represents we call an allele. Let’s
see another example (SHOW POWERPOINT SLIDES 1, 2). In this example, the
alleles are for Tall (T) versus short (t).
(Tell students to start taking notes on Vocabulary Note-Sheet [Sheet A])
An allele is a gene from a parent. A gene is basically the scientific name for a
trait. We each have two copies of EVERY gene from our parents in 99% of all of
our cells. In the case of the peas, the YELLOW pea, YY, has two alleles which
are both Y. The GREEN pea has two alleles, which are yy. Each child or
offspring of the parents will have two alleles for each gene as well, as we can
see from the Punnett Square, the diagram we have drawn here on the board.
If there is two dominant alleles, the dominant trait shows.
(DRAW ON BOARD YY = YELLOW)
If there is one dominant and one recessive, the dominant still shows.
(DRAW ON BOARD Yy = YELLOW)
Only if there are TWO recessive alleles will the recessive trait show.
(DRAW ON BOARD yy = GREEN)
Another scientific name we are going to use for trait is phenotype. Phenotype
refers only to the visible trait in the offspring. So the phenotype for the Yy
offspring is YELLOW. Another scientific word we use in genetics is genotype.
Genotype simply refers to the actual combination of alleles, so in this case the
genotype is Yy.
(MAKE SURE STUDENTS HAVE DEFINITIONS FOR ALL WORDS ON [SHEET A]. Go
over any that they missed and give them the definition)
TRAIT: a physical characteristic of a living creature (rasgo en español)
GENE: the genetic code which makes the trait (misma palabra en español)
PHENOTYPE: the visible trait which the genes express, often referring to the
symbols (example Yy is YELLOW)
GENOTYPE: the non-visible genetic code which an individual might have and is
expressed in symbols (example Yy is YELLOW dominant, GREEN recessive)
ALLELE: single copy of gene from parent, expressed as “Y”
DOMINANT: the allele which will always dominate (en español dominar)
RECESSIVE: the allele which only expresses if there is no dominant allele (en
español recesivo)
PUNNETT SQUARE: math tool to help calculate the offspring of a cross of two
parents for a particular gene
BEYOND:
(30 minutes)
(SHOW SLIDE 3 for students to reference while they work together on class
exercise.)
Have students work in pairs on practice worksheet [Sheet B], predicting the
various phenotypic ratios of crosses. Monitor student learning and give help
to those students who are confused. At the end of the exercise, if students
finish, go over the answers to each of the seven examples from [Sheet B].
(IF THERE IS EXTRA TIME, if the students finish the exercises early, present a
TWO-TRAITED Punnett Square, like YyGg x yygg as a “lead in” to next class.)
HOMEWORK: Use textbook to help you answer the questions on [Sheet C] as
practice using the new vocabulary and concepts. Answer questions in English
or language of choice.
LESSON #2: GENETICS, PROBABILITY, INDEPENDENT ASSORTMENT, MEIOSIS
Standards: Biology/Life Sciences: Genetics
3. A multi cellular organism develops from a single zygote, and its phenotype
depends on its genotype, which is established at fertilization. As a basis for
understanding this concept:
a. Students know how to predict the probable outcome of phenotypes in
a
genetic cross from the genotypes of the parents and mode of inheritance
(autosomal or X-linked, dominant or recessive).
b. Students know the genetic basis for Mendel's laws of segregation and
independent assortment.
2.
a. Students know meiosis is an early step in sexual reproduction in
which the pairs of chromosomes separate and segregate randomly during
cell division to produce gametes containing one chromosome of each
type.
d. Students know new combinations of alleles may be generated in a
zygote through the fusion of male and female gametes (fertilization).
e. Students know why approximately half of an individual's DNA
sequence
comes from each parent.
f. Students know how to predict possible combinations of alleles in a
zygote from the genetic makeup of the parents.
OBJECTIVE: Students will flip coins to demonstrate and predict probability
(versus reality). Students will learn how probability relates to Punnett Squares.
Students will learn the terms: gamete, segregation, probability, homozygous,
heterozygous, independent assortment, diploid, haploid, meiosis, crossing-over,
and how they relate to genetics. Students will take very small quiz to assess
their progress with this very challenging material (challenging for all students!)
to help teacher know where the class stands with their understanding.
PRE-INTO:
(5-10 minutes)
Go over previous nights homework. Ask for students to put one or two
examples on the board. Check for understanding, review “true-breeding.”
INTO:
(10 minutes)
Students will flip coins with a partner for as many times as they can in ten
minutes. Students record data of heads or tails and tally totals at the end.
THROUGH:
LECTURE:
(40 minutes)
How many heads did you get versus tails? If this were an ideal world, and we
flipped our coins 480 times, how many heads and tails would we get?
(240 each)
So what percentage would that be? 50%? This so if you flip a coin, you have a
50% chance of getting a heads, or a 1 in 2 chance. That is a probability, which
some of you may recognize from math class. Probability (en español,
probabilidad) is very important in genetics. Let’s go back to our Punnett
Squares from last class.
(Do a quick Punnett Square on whiteboard of Zz x Zz and let students fill in the
boxes, assessing their grasp of the previous lesson)
So, ideally, if there are four offspring, what is the probability of getting the
recessive phenotype?
(wait time….. 1 in 4 or 25%)
Good. There is a scientific name for the recessive phenotype from this
example, please write the definition down on your Vocabulary Note-Guide
[Sheet D]. Scientists call this homozygous. Homo- means same and –zygous
refers to the alleles that the offspring has. Thus, because there are two small
z’s, zz is homozygous. The other offspring from our example on the board are
called heterozygous. Hetero- means different and –zygous again refers to the
alleles of the offspring, which in this case are different, one dominant Z and
one recessive z, Zz.
(Now put up on whiteboard “blank” Punnett Square for two traits, RrYy x RrYy.
Ask students to fill in each box, walk them through it).
As you can see here, and also on this slide [SLIDE 4], we have a mixture of
different phenotypes and genotypes. Let’s count them. (Have class count)
How many are dominant for both phenotypes?
____________
How many are dominant for R but recessive for y?
____________
How many are dominant for Y but recessive for r?
____________
How many are recessive for both r and y?
____________
The resultant (resultado en español) phenotype ratio is 9 : 3 : 3 : 1. Gregor
Mendel found this ratio in his experiments, and what he realized was that,
really, the R and the Y don’t affect each other. The traits occur independently
of each other, as we can see by the YELLOW ROUND peas, the YELLOW
WRINKLY peas, the GREEN ROUND peas, and the GREEN WRINKLY peas. We get
all four varieties from this cross-pollination. This is called the law of
independent assortment (configuración independente). The two genes
operate independently of each other, and we get all possible varieties of peas.
There is one exception I have to mention about this phenomenon of dominant
and recessive. Some traits are very clear about which is dominant and which is
recessive. However, some traits are not. This is called incomplete dominance.
[SHOW SLIDE 5]
Let’s take a step back. How is all this possible? How does this work? In order
to understand how this works, we need to look at how these plants are
reproducing. Plants undergo sexual reproduction, like animals as well.
Who can tell me which plant parts are responsible for their reproduction?
(Pistil and Stamen, which hold pollen and ovum)
BEYOND:
KINESTHETIC DEMONSTRATION:
(25 minutes)
When a living thing undergoes sexual reproduction, it makes an offspring which
has the genes of both parents. In order to demonstrate how this happens,
I need a volunteer to step to the front.
(Hand Volunteer 1 yarn-Velcro chromosome model)
Here __________ (student name) is a cell and she is holding her chromosome.
Who remembers mitosis from first semester? If she now wants to divide, what
is the first step she must complete?
(She must duplicate the chromosome so there are two copies. After students
answer, give her 2nd yarn-Velcro chromosome)
Okay, so now she has two sets of chromosomes.
I need another volunteer.
Stand very close to her, you are part of her expanding cell during Prophase I.
Okay, now you both face each other and hold both chromosomes between both
of your hands. The chromosomes are lined up in Metaphase I, which is just
like we studied in mitosis last semester. Who remembers the next step?
(Anaphase)
In Anaphase I, chromosomes are pulled to the other side of the cell, so pull one
chromosome towards yourself, separate yourselves into two new cells.
Now I need two more volunteers.
Stand next to each of the cells, and start the process all over again, but this
time the chromosome will separate at the Velcro into four cells.
(DIRECT STUDENTS until they each have one single strand of yarn).
Great job, volunteers! You are now what scientists call gametes (en español se
usan gameto, unas células sexuales). You are all familiar with what a gamete
is, because pollen is a male gamete, sperm is a male gamete, and female eggs
are gametes. A gamete is a cell from a parent which has only one copy of a
gene and combines with another cell which completes sexual reproduction.
The new cell is called the zygote, so if the parents gave offspring the same
copy of a particular gene, it will be HOMOZYGOUS, like we learned earlier.
[SLIDE 6]
Let’s see an example. Class, if our gene of interest is TALL, which is dominant,
and Maria has genotype of Tt, what kind of gametes could she make? (T and t)
And if Marco over here is short, with tt, what kind of gametes could he make?
(t and t)
So if Maria and Marco mated and their gametes combined to form a zygote,
what are the possibilities of offspring. As a Quick Write, make a Punnett
Square right now for Maria (Tt) and Marco (tt) mating.
(Go over answers as a class after 1-2 minutes of silent writing/calculating)
SMALL QUIZ:
(10 minutes)
Very quick assessment at the end of the two lengthy class lectures and
activities to check for student understanding. See [Sheet E]
INTRODUCTION TO GENETICS
Note-taking Guide
VOCABULARY: write out definition in English (or your preferred
language). When possible, draw a picture to go along with the
words.
GREGOR MENDEL =
TRAIT =
CROSS-POLLINATE =
DOMINANT =
RECESSIVE =
SILENCE =
ALLELE =
GENE =
PUNNETT SQUARE =
PHENOTYPE =
GENOTYPE =
HOMEWORK/TAREA (10 points)
1) Choose a trait which two parents have, using the new concept of
alleles we learned today. Draw the different kinds of offspring the
parents will have.
Escoje un rasgo que tiene dos padres, usando el concepto de
“alleles” que aprendemos hoy. Dibujen todos los tipos de niños
que podrían nacer de esta pareja.
2) Using the textbook, page 263, explain in your own words what is
meant by the term “true-breeding.” Why did Mendel have to use
plants which were “true-breeding” for his experiment?
Usando el libro, pagina 263, expliquen en tus palabras propias que
significa “true-breeding.” Por qué Mendel tuvo que usar plantas que
eran “true-breeding” para su experimento?
GENETICS
Note-taking Guide
VOCABULARY: write out definition in English (or your preferred
language). When possible, draw a picture to go along with the
words.
TRUE-BREEDING =
PROBABILITY =
HOMOZYGOUS =
HETEROZYGOUS =
INDEPENDENT ASSORTMENT =
INCOMPLETE DOMINANCE =
PROPHASE I and II =
METAPHASE I and II =
ANAPHASE I and II =
GAMETE (male and female) =
ZYGOTE =
NAME nombre ______________________________ period
GENETICS QUIZ (10 points)
1.
a)
b)
c)
d)
1
2
3
4
5
Who was Gregor Mendel? (1)
a rock star
a duke
a teacher and scientist
a novelist
2. Fill in the boxes for the following cross of tall versus short plants: (2)
Llena las cajas con los símbolos correctos para esta cruz de plantas altas o bajas.
3. If one of the offspring exhibits tt, what term best describes it?
Cual es la palabra major que describa un resultado que exhibe tt? (1)
a)
b)
c)
d)
probability
Punnett Square
recessive
gene
4. Draw the offspring that result from crossing Tt x tt, where T is tall and t is
short. There should be four.
Dibuje niños resultados de cruz de Tt x tt, deben ser cuatro en total. (4)
5. (2)
Give an example of a PHENOTYPE:
Da un ejemplo de PHENOTYPE:
Give an example of a GENOTYPE:
Da un ejemplo de GENOTYPE:
6
CONCEPT MAP