Population Genetics: The Hardy Weinberg Equation

This fun lab simulation should guarantee that your students understand the Hardy Weinberg Principle!  

I talk to a lot of biology teachers. Everyday. Some are in my school, some are at other schools in my district, others I know "virtually" from various message boards that I read and post to.  Through these communications, I have come to realize that many biology teachers do not include the Hardy-Weinberg Principle in their lesson planning.

I know that all biology teachers have their own "order of events" but for me a unit on genetics, followed by my unit on evolution is perfect.  In fact, I would be hard pressed to do it any other way.  The Hardy-Weinberg Principle is the link between genetics and evolution.  It is the proof that we offer to our students that populations are constantly changing and evolving.  It allows us to mathematically show that the frequency of a particular allele in a population can change over time.

Simply put:  Evolution is any change in the frequency of alleles in a population.  Evolution is the result of changes in the gene pool.  Two men, G. H. Hardy and W. Weinberg, proposed a mathematical model for detecting changes in the gene pool.

The Hardy-Weinberg Principle states:  “In the absence of mutation, migration, and natural selection, and in a population that is sufficiently large, the frequencies of alleles will remain the same.”  

The Hardy-Weinberg Principle is represented in the equation:

No population is free of these agents of change.  The Hardy-Weinberg equation is used to detect changes in the population from one generation to the next.  Since no population in nature is free of mutations, migrations, and natural selection, and since mating is rarely completely random in nature, of what value is the Hardy Weinberg Principle?  It allows us to detect changes in the gene pool, and therefore, determine that a population is in a state of change....Evolution!

My experience with my own students is that some of them have a little trouble grasping this concept. After introducing the topic and working through quite a few practice problems, I do a simulation lab.

Purpose of the Lab:  
1.  To simulate how changes in the gene pool might occur by using the class as a breeding population of individuals. 
2.  To observe how the Hardy-Weinberg equation is used to detect changes in allele frequencies in a population.

Materials:   PTC test papers,  Calculator,  Allele cards,  Coins, Pencil and paper

Safety Precautions:   None

The student handouts for this lab are numerous.....12 pages!  I usually run off a class set and have students record all of their information on notebook paper. I use the class set throughout the day, and then I file them away for use the next year.

I have also included an 11-page teacher guide.  The teacher guide has tips and tricks for making the lab successful as well as answers to questions and solutions to problems.  Sample data is included to give you an idea of what to expect in the simulation.

Students begin the lab by determining the frequency of an allele in the class population.  I like to use PTC paper to determine if students are tasters or nontasters. But if PTC paper is not available, you can choose another trait such as the presence or absence of dimples, or the ability to roll the tongue.  From the number of recessive individuals in your class, the value of q can be determined.  From that point, the students will determine what percentage of the class is homozygous dominant and heterozygous for the given trait.

Next, students will run three simulations:  (1) Testing the Hardy-Weinberg Principle, (2) Testing the Hardy-Weinberg for Selection Pressure, and (3) The Heterozygote Advantage.

Students will begin the simulation as heterozygous individuals and will use allele cards to generate offspring. Students proceed through several generations of "mating" and the data is used to test the different conditions of the Hardy-Weinberg Principle.

During each simulation, students will determine the frequency of the dominant and recessive allele and note how the frequency of p and q change in various scenarios. The lab concludes with follow up questions and 8 additional practice problems involving the Hardy-Weinberg equation.  

The end result?  My students have mastered the concept and are able to work problems involving the Hardy-Weinberg equation.

Good luck, and have fun teaching!

Lab:   Population Genetics,  The Hardy-Weinberg Principle, and Evolution

Springtime is the Perfect Time to Teach the Plant Kingdom!

Introduction to the Plant Kingdom

Complete Teaching Unit

(Bundle of Products)

By far, the most popular items in my TpT store are my complete unit plan bundles.  These unit plan bundles contain everything you need to teach a thorough and complete unit to a typical biology or life science class.  All of my unit plan bundles come with a colorful and engaging PowerPoint presentation, notes for the teacher, notes outline for the student, several labs, homework assignments, daily quizzes, crossword puzzles for vocabulary review, review PowerPoints, and a final unit test.

I have just recently completed my latest unit plan bundle.  It is called "Introduction to the Plant Kingdom."  No biology class is complete without a survey of the Kingdom Plantae.  In short, life could not exist on earth without the plants.  Plants are the producers in every food chain.  Plants carry out photosynthesis, producing organic compounds from inorganic compounds.  The plant uses much of this glucose as a source of energy, but a portion of the glucose is passed up the food chain.  This sustains life on earth.  Not only do plants produce food for all heterotrophs, they also provide the oxygen that fills our atmosphere.

Simply put, this is one of the “must-teach” topics in a biology class!

This complete teaching bundle contains 10 separate products bundled into one digital download.  When appropriate, I have included each product as a Word document, and I have also included each product in PDF form.  Each of these products is sold separately in my TpT store, but buying the entire unit in one download will save you money.  If these products were purchased separately, the total cost would be $30.00.  I am selling this bundled package of products for $19.99.

All products have answer keys included.

The bundled unit contains the following.  Details of each product can be found below.

1. A 97-Slide PowerPoint with Notes for Teacher and Student

2. A 130-Slide Review PowerPoint

3. Lab:  Liverworts, Mosses, and Ferns

4. Lab: Transpiration in Plants

5. Lab:  Diversity in the Plant Kingdom (A Living Plant Lab)

6. Homework Question Packet of 99 questions

7. A Set of 3 Quizzes

8. A set of 2 Crossword Puzzles

9. Graphic Organizer Study Aid

10. Unit Test of 100 Questions

CLICK ON PICTURE TO VIEW LISTING IN MY TPT STORE

Topics covered by this Unit:

1.  Introduction to Plants:  Importance of plants to life on Earth, definition of a plant.

2.  Plant life cycle:  Alternation of generations, sporophyte and gametophyte generations, haploid and diploid phases, the production of spores by meiosis, flow chart showing alternation of generations.

3.  The Transition of Plants to Land:  The algae were the first plants on earth, evidence that algae are the ancestors to the land plants, advantages to a life on land, challenges to a life on land.

4.   Cladogram showing the evolution of mosses, liverworts, ferns, gymnosperms, and angiosperms from ancestral algae.

5.   Traits of the True Land Plants:  Alternation of generations, spores produced by sporangia, multicellular gametangia, apical meristems, vascular tissue, nonmotile gametes, root system, protection from dehydration.

6.   Classification of Land Plants:  Vascular and nonvascular land plants, bryophytes, tracheophytes, seedless plants, seed plants, gymnosperms, angiosperms, monocots and dicots.

7.   Flow chart showing the classification of the land plants.

8.   Bryophytes:  Characteristics of bryophytes, examples of bryophytes, explanation of why the bryophytes are still tied to a watery existence, bryophytes are nonvascular plants, bryophytes have a dominant gametophyte generation.

9.   Example:  The Liverworts.  Characteristics of liverworts, students will draw and label the structures of a liverwort, liverwort life cycle.

10. Example:  The Mosses.  Characteristics of mosses, students will draw and label the structures of a moss, moss life cycle.

11. The Seedless Vascular Plants:  The evolution of vascular tissue, the importance of xylem and phloem, why ferns are classified as seedless vascular plants.

12. Characteristics of ferns, students will draw and label the structures of a fern, fern life cycle.

13. The Seed Plants:  Seed plants are the dominant plants on earth, two groups of seed plants, gymnosperms and angiosperms, the advantage of having a type of reproduction free from water, adaptations seen in the seed plants, cones and flowers, pollen, seeds, the evolution of seed plants.

14. Characteristics of gymnosperms.

15. Characteristics of angiosperms.

16. Comparison of monocots and dicots.

Below I have listed each product with a brief description.  I have included a hyperlink to each individual product.  You can click on the links below to view a complete and thorough description of each product and download a free preview of the product.

Introduction to Plants PowerPoint with Notes for Teacher and Student

It consists of 97 slides that are colorful, informative and visually stimulating.  Pictures and diagrams are included that will greatly enhance your instruction to your students.  This product also includes a set of notes for the teacher (12 pages) and a set of notes in outline form for the student (17 pages).  Graphics, diagrams, clip art, and photographs were chosen to capture the attention of the student as the lesson is being taught.

Set of 3 Quizzes

This product contains 3 quizzes that can be used at various stages as the unit is being taught.   I always break up the content into manageable amounts of study material and give my students several small quizzes on this material prior to the unit test.

Homework and Study Guide

This document is a 9-page student worksheet consisting of 99 questions.  As I am teaching my introductory unit on plants, I assign a portion of these questions for homework each night.  This document provides quality homework assignments and ends up being a completed and thorough study guide for the unit test.

PowerPoint Review Questions

This PowerPoint consists of 130 slides of questions and answers and  provides an excellent review for the chapter test.

Slide Lab:  Liverworts, Mosses and Ferns

This is an in depth lab that looks at the structures of mosses, liverworts, and ferns.  You will need quite a few prepared slides to be able to do this lab.   Students are asked to compare Bryophytes to Tracheophytes and will discuss which are truly adapted to life on land and why.

Lab:  Plant Transpiration

Purpose:

1.  To measure the amount of water lost from the leaves of a plant over a given amount of time.

2.  To calculate the surface area of leaves on a plant.

3.  To calculate the rate of transpiration from the leaf under different environmental conditions.

Lab:  Diversity of the Plant Kingdom (A Living Plant Lab)

In this lab, students will circulate through 8 different lab stations.  At each station, the student is required to make a drawing and answer 5 to 8 questions.  The eight stations are as follows:

Station #1  Living Mosses

Station #2  Living Ferns

Station #3  Fern Gametophyte

Station #4  Living Gymnosperm

Station #5  Pine Pollen

Station #6  Living Angiosperm with Flower (dicot)

Station #7  Living Angiosperm (monocot)

Station #8  Fruits

Set of 2 Crossword Puzzles

I love crossword puzzles and I use them all the time in my biology classes.  Crossword puzzles are a great way to reinforce and review the many, many vocabulary words covered in a biology class.   Crosswords not only help with strengthening vocabulary, they also provide invaluable spelling practice.

Graphic Organizer Study Aid

This is a simple study skill graphic organizer that I use with my Biology students to help them prepare for the unit test.  The student will compare and contrast the traits found in liverworts, mosses, ferns, gymnosperms, and angiosperms.*NOTE:  This is one of my FREE items in my TpT store.  Even if you do not purchase this unit plan bundle, please download this freebie!!

Unit Test

This unit test has 100 questions.  There are 63 fill in the blank questions, 11 matching questions, and 26 multiple choice questions.

This final link will return you to the product-listing page on TeachersPayTeachers.com.   

Happy Teaching!

Introduction to Plants:  A Complete Unit Plan

 

Genetics in the Laboratory

Do you want to do a great genetics lab with your students, but don't have time for fruit flies?

Having enough "time" is an issue for me every single year!  I finally had to come to the realization that my fruit fly genetics lab would have to go.  It is such a great lab, but just too time consuming.

Now we grow corn!  It only takes a few minutes to plant and you are practically done!  I do have my students water their corn every few days, and in about 2 weeks we are ready to do the lab.

In corn, green stem (due to chlorophyll production) is dominant over albino stem.  I order seeds that are the F-2 offspring of heterozygous parents.  The expected ratio when the seeds grow is, of course, 3/4 green stem and 1/4 albino stem.  Students then compare the expected ratios to the actual number of each type of offspring observed.

For an added component to the lab, have the students consider the effect of the environment on the expression of the gene. When the seeds are first planted, I have half the class place their trays on a table in front of a window.  The other half of the class place their trays in a cabinet in complete darkness. When the seeds finally sprout and grow, we compare the number of albinos grown in the dark to the number of albinos grown in the light.

For those plants grown in the light, the results are fairly close to the expected 3:1 ratio.  But, the seeds grown in the dark are a different story.  100% of the seeds grown in the dark turn out to be albino.

After this first observation, all trays are left in the light for 48 hours, and a second observation is made two days later.  Miraculously : )  about 3/4's of the albinos from the dark trays have now turned green.

Students quickly determine that the environment plays a very important role in gene expression.

If you choose, you can order seeds showing two traits as seen in the photo to the left.  When these seeds were grown, students could determine the expected and actual numbers of green and albino stems as well as the number of tall and dwarf plants.

You can view this lab in my TpT store by clicking this link:

Lab: The Effect of the Environment on Gene Expression

Or, you might want to try this as a "Virtual Lab" for distance learning and 1:1 classrooms.  You can check out the "Virtual Lab Version" by clicking this link.

👉 Check this Blog Post: For additional reinforcement of Mendelian genetics concepts, students can practice with this monohybrid genetics worksheet that focuses on Punnett squares and dominant and recessive traits.

👉 Check this Blog Post: Genetics Warm Ups and Bell Ringers

Short daily practice activities can help reinforce genetics vocabulary and problem solving skills. These genetics warm ups provide quick review questions that build student confidence with concepts like dominant and recessive traits, Punnett squares, and inheritance patterns.