Unit: Genetics – Block 2

Introduction

• Lesson topic: Intro to Genetics• Length of Lesson: 45 min lesson; 30 min lab• VA Standards of Learning:

° BIO 6.d – Students will investigate and understand how to predict the inheritance of traits based on the Mendelian laws of heredity

Cognitive Objectives for All Students:

• SWBAT understand how to apply mathematical principles of probability to Mendel’s laws of heredity in order to predict the results of simple genetic crosses• SWBAT demonstrate knowledge by completing data sheet• SWBAT demonstrate prior knowledge by completing entrance ticket anticipatory guide• SWBAT participate – at least by listening – in the class discussions• SWBAT participate in small group probability practice, discussions, and lab work• SWBAT rate themselves on their understanding of the content by reviewing the anticipatory guide after the lesson; and the exit ticket

Cognitive Objectives for Some Students:• SWBAT participate – by contribution – in the whole class discussions and probability work• SWBAT use critical thinking skills for how Mendelian principles apply to meiosis• SWBAT assist other students in lab work and probability work• SWBAT decipher how the media portrays mutations

Materials and Advanced Preparation

• Miller and Levine’s Biology textbook (Miller & Joseph, 2008): Chapter 11.1 – 11.3• PowerPoint lecture with accompanying fill-in-the-blank handout• Data Sheet• Life cycle diagrams for

° Rhizopus ° A moss ° A fern ° An animal, such as a human° Chlamydomonas or Ulva° Nitella

Teaching and Learning Sequence

• Introduction/Anticipatory Set ° Begin with an oral overview of what was taught the day before, answering questions as needed (Reflection – previous day)° Have the students fill out an anticipatory guide (attached) for the understanding of mathematics, Mendel, and simple genetics (Preparation) ° After discussing the above, ask if students know what plants Mendel worked with, simple genetics, and important vocabulary

• Lesson Development (Assistance)° Quick overview of who Mendel was° Discuss the importance of genes and dominance° Discuss the process of segregation, having the students draw representative figures in their personal journals (see attached email) ° Explain genetics and probability, with having students work examples on the board° Introduce Punnett Squares° Have students summarize Mendel’s Principles in their personal journals

° Discuss the exceptions: incomplete dominance and codominance; have students summarize in their personal journals ° Discuss the differences between polygenic traits and multiple alleles; have students summarize in their personal journals ° Explain the effect of the environment on genetics; have students discuss Chernobyl and Hiroshima (from articles they gathered from last night’s homework)

• Closure ° Oral: Ask students the difference between complete dominance, incomplete dominance and codominance? The difference between multiple alleles and polygenic traits? (Reflection)° Group work: Separate them into their groups to do probability examples first in their seats, then on the board; Discuss as a group the anticipatory guide: have their feelings changed? Have them discuss and write down a movie that deals with people whose genetics have changed do to environmental factors? (Reflection) ° Students will review in their groups the handouts on life cycles of various organisms and complete the Meiosis lab (that was started last class) (Virginia Department of Education, 2010) ° Have students fill in the data table and conclusion (exit-ticket) for assessment; mutations lab ° During the last five minutes, have students relate this lab to Mendel’s Laws of heredity° Assign chapter 11.1 thru 11.3 to read again for homework in preparation of the next day’s lesson; paying particular attention to Punnett Squares in preparation of the next day’s lab; mutations lab

Homework

• Assign chapter 11.1 thru 11.3 to read again for homework in preparation of the next day’s lesson; paying particular attention to Punnett Squares in preparation of the next day’s lab; mutations lab

Assessment

• Formative – Asking the students questions during the lesson to re-enforce the segment being taught; anticipatory guide; exit-ticket about movie that deals with environmental effects on genetics/conclusion on the lab; group work on probability problems • Summative – After completion of the lab, students will be evaluated on their data sheet, which incorporates the lesson; mutations lab group project due in two weeks (requirements below)

References

Miller, K., & Joseph, L. (2008). Biology. Pearson Prentice Hall.

Virginia Department of Education. (2010). Science: Biology: Scope and Sequence. Retrieved August 31, 2010, from Virginia Department of Education: http://www.doe.virginia.gov/testing/sol/scope_sequence/science_scope_sequence/scopeseq_science_biology.pdf

Appended Materials

• Instructional Content and Strategies Organizer • Curriculum Framework Document • Anticipatory Guide• Data Sheet

Instructional Content and Strategies Organizer

Instructional Content Apply mathematical principles of probability to Mendel’s laws of heredity in order to

predict the results of simple genetic crossesInstructional Modifications to

ASSIST StudentsMajor Instructional Strategies Instructional Modifications to

CHALLENGE Students Extend lesson as

needed to make sure all students understand lesson

Additional information on my website with links to improve comprehension of material

Students with reading disabilities: if they do not understand the text they read, the visual/auditory lesson should enhance comprehension; group work for probability practice and lab work

Auditory learners: learn by discussions in the class; group work for probability and lab work

Visual learners: learn by the PowerPoint lesson that includes pictures, charts, and graphs (attached in email)

Students with ADHD: they get to walk to the board for the probability activity; group work with lab

Oral review Anticipatory guide Visually-stimulating

lesson Begin lab

Using critical thinking skills to ascertain the importance of Mendel’s principles and their application to meiosis

Mutations lab project: involves research, writing, and oratory skills

Extra credit on mutations lab project

Assist classmates with lab work

Anticipatory Guide

Place a √ (checkmark) next to the statements that you think are true:

1. _____ Mendel used roses to study genetics

2. ___√__ The principle of dominance says that some alleles are dominant while others are recessive

3. ___√__ The Punnett square is used to predict genetic variance

4. _____ Heterozygous means the same, while homozygous means different

5. ____√_ Phenotypes = physical characteristics, Genotypes = genetic characteristics

6. ___√__ Ratios are often expressed as a fraction

7. _____ Incomplete dominance is when both alleles contribute to the phenotype (red flower + white flower = flower with red and white spots)

8. ___√__ The environment can affect genetics

9. _____ Self-pollination occurs when the pollen of one plant attaches to the stigma of another plant

10. __√___ Parents = P generation, offspring = F generation

Introduction to Genetics Lecture Notes

Gregor MendelWorked with common garden peas to study genetics

True-breeding plants are plants that, if allowed to self-pollinate, would produce offspring _________________ to themselves

To prevent self-pollination, Mendel cut off the male reproductive structure off one plant. He then pollinated the plant with pollen from another plant - __________-pollination

Genes and DominanceMendel studied seven different pea plant traits - a specific characteristic, such as seed color

or plant height that varies from one individual to another

The original pair of plants are the _____ generation

The offspring are called the _______ generation

The offspring of crosses between parents with different traits are called ________________

Genes and DominanceThe F1 generation had the character of only of the parents

Mendel drew two conclusions Biological inheritance is determined by factors that are passed from generation to

the next The principle of dominance - some alleles are ________________and others are

_______________

Genes are _____________ factors that determine traits

Alleles are different ___________ of the __________

Segregation

Had the recessive alleles disappeared, or were they still present in the F1 plants?

He allowed the F1 plants to self-pollinate to produce the F2 generation, in which all of the recessive alleles had reappeared

When each F1 plant flowers and produces gametes, the two alleles segregate from each other so that each gamete carries only a single copy of each gene. Therefore, each F1 plant produces two types of gametes - those with alleles for tallness and those with the allele for shortness

Genetics and ProbabilityThe ____________________ that a particular event will occur is called probability

The principles of probability can be used to predict the outcomes of genetic crosses

Punnett SquaresThe Punnett square can be used to predict and compare the genetic variations that will

result from a cross

Homozygous means that the organism has two _____________ alleles for a particular trait

Heterozygous mean that the organism has two ______________alleles for a particular trait

Phenotypes are ________________characteristics

Genotypes are _________________ characteristics

Probability and SegregationFor each of Mendel’s seven crosses, ¾ of the plants showed the trait controlled by the

dominant allele, while ¼ of the plants showed the trait controlled by the recessive trait - a ________ ratio

Probabilities predict the average outcome of a large number of events - the larger the number of offspring, the closer the resulting numbers will get to expected values

The Two Factor Cross: F1Two different genes passing from generation to another

First, Mendel crossed tree-breeding plants (RRYY x rryy)

All of the F1 offspring produced the dominant genes

The Two Factor Cross: F2

Mendel knew that all the F1 plants were heterozygous for both genes

The F2 generation shows how alleles segregate

Since the alleles for both genes segregated independently of each other (independent assortment), the ratio was _____________

The principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes. Independent assortment helps account for the many genetic variations observed in plants, animals, and other organisms

Summary of Mendel’s PrinciplesThe inheritance of biological characteristics is determined by individual units known as

genes. Genes are passed from parents to their offspring

In cases in which two or more alleles of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive

In most sexually reproducing organisms, each adult has two copies of each gene - one from each parent. These genes are segregated from each other when gametes are formed

The alleles for different genes usually segregate independently of one another

Incomplete DominanceCases in which one allele is ___________completely dominant over another

The heterozygous phenotype is somewhere between the two homozygous phenotypes

CodominanceBoth alleles contribute to the _________________

Multiple AllelesMany genes have more than two alleles

This does not mean that an individual can have more than two alleles, it only means that more than two possible alleles exist in a population

Polygenic TraitsTraits controlled by two or more genes are said to be _________________ traits

Genetics and the Environment

The characteristics of any organism are not determined solely by the genes it inherits, but by interaction between genes and the ____________________

Genes provide a plan for development, but how that plan unfolds also depends on the environment