Simulating Color Vision Genetics Evolution: Teaching Natural Selection | Lecture notes Genetics

GRADE LEVEL

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SETTING

Teacher and Youth Education | 2015

Page 1

Color Vision Genetics Evolution Simulation

7 - 12th

Life Sciences; Analyzing and Interpreting Data; Stability and Change

Prep: 45 minutes; Activity: 60 minutes

Classroom

SCIENTIFIC TERMS FOR STUDENTS

» chromosome: a coiled thread of DNA packaged into a rod

shaped structure that contains hereditary information

» gene: a segment of DNA, at a specific location on a

chromosome, that is the basic unit of heredity

» gene pool: all the possible traits that can be handed down

from one generation to the next in a population

» sex-linked gene: a gene that is located on the same

chromosome that determines gender

» gamete: a type of cell that fuses with another cell to form

a zygote, which can give rise to a new, genetically distinct

individual.

» dichromatic: refers to vision that can detect two

wavelengths of light

» trichromatic: refers to vision that can detect three

wavelengths of light

» selective pressure: an environmental condition in which

individuals that are better adapted to their environment

are more likely to survive and reproduce than others of the

same species

» population: all members of one species in a particular area

» species: a group of organisms that share their most recent

common ancestor and can produce viable offspring

» primate: any of various mammals of the order Primates,

having a highly developed brain, eyes facing forward,

a shortened nose and muzzle, and opposable thumbs.

Lemurs, monkeys, apes, and humans are examples of

primates.

» colorblindness: the inability to perceive certain color

differences

» deuteranopia: a form of color blindness where

distinguishing between red and green are the main problem

colors. In deuteranopia, the third color sensitive gene is

either missing or malfunctioning, rather than simply not

working well.

OVERVIEW

In this lesson, students will participate in a natural selection

simulation, flipping pennies to mimic the probability of passing

on certain traits. The traits are the three genes for color-vision,

found on the X chromosome. In the simulation, students will

simulate 6 generations of primates, and track how the gene

pool changes over time. The activity loosely mimics some of

the mechanisms that led to the evolution of our own improved

color vision.

MATERIALS

6 different colors of post-it notes. Each color needs as

many post-its as students in your class (note: red and

goldenrod are the first two colors used in the example

PowerPoint; it is not strictly necessary to match, but

helpful.)

6 giant stickies or a lot of blackboard/dry-erase board real

estate

pennies, 1 for each student

power point presentation and projector

pens or pencils, 1 for each student

additional tape (if post-its are not sticking by themselves)

OBJECTIVES

In this lesson, students will:

1. Model natural selection by participating in a

simulation using probability and selective pressure

2. Learn about color vision and its genetic history in

humans and other primates.

3. Understand the difference between dichromatic and

trichromatic vision

4. Understand how sex-linked traits can affect males

and females in different proportions

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Color Vision Genetics Evolution Simulation 7 - 12th Life Sciences; Analyzing and Interpreting Data; Stability and Change Prep: 45 minutes; Activity: 60 minutes Classroom SCIENTIFIC TERMS FOR STUDENTS » » » » » chromosome: shaped structure that contains hereditary information gene: chromosome, that is the basic unit of heredity gene pool: from one generation to the next in a population sex-linked gene: chromosome that determines gender gamete: a zygote, which can give rise to a new, genetically distinct individual. a segment of DNA, at a specific location on a a type of cell that fuses with another cell to form all the possible traits that can be handed down a coiled thread of DNA packaged into a rod a gene that is located on the same

» » » » » » » » dichromatic: wavelengths of light trichromatic: wavelengths of light selective pressure: individuals that are better adapted to their environment are more likely to survive and reproduce than others of the same species population:species: common ancestor and can produce viable offspring primate: having a highly developed brain, eyes facing forward, a shortened nose and muzzle, and opposable thumbs. Lemurs, monkeys, apes, and humans are examples of primates. colorblindness: differences deuteranopia: distinguishing between red and green are the main problem colors. In deuteranopia, the third color sensitive gene is a group of organisms that share their most recent any of various mammals of the order Primates, all members of one species in a particular area refers to vision that can detect two refers to vision that can detect three a form of color blindness where the inability to perceive certain color an environmental condition in which

OVERVIEW In this lesson, students will participate in a natural selection simulation, flipping pennies to mimic the probability of passing on certain traits. The traits are the three genes for color-vision, found on the X chromosome. In the simulation, students will simulate 6 generations of primates, and track how the gene pool changes over time. The activity loosely mimics some of the mechanisms that led to the evolution of our own improved color vision. MATERIALS 6 different colors of post-it notes. Each color needs as many post-its as students in your class (note: red and goldenrod are the first two colors used in the example PowerPoint; it is not strictly necessary to match, but helpful.)6 giant stickies or a lot of blackboard/dry-erase board real estatepennies, 1 for each studentpower point presentation and projectorpens or pencils, 1 for each studentadditional tape (if post-its are not sticking by themselves) either missing or malfunctioning, rather than simply not working well.

In this lesson, students will: 1. 2. 3. 4.^ OBJECTIVES Model natural selection by participating in a simulation using probability and selective pressureLearn about color vision and its genetic history in humans and other primates.Understand the difference between dichromatic and trichromatic visionUnderstand how sex-linked traits can affect males and females in different proportions

Color Vision Genetics Evolution Simulation

TEACHER PREP 1. 2. 3. It is first- much of the simulation will make more sense.Make a set of ‘Generations” posters (or make space on a white-board or chalk board- you will need a lot of room.) You will need six posters total, From Generation 0 to Generation 6.Make the “Generation 0” primates, one for each student in your class. You will need a minimum of 20 primates/ students to do the activity. The initial primates should be 50/50 male and female. Of those, 15-20% of them should have ‘3-color vision’. EXAMPLES: highly suggested EXAMPLE #1: Class of 30 3 XX 2 XY 12 XX* 13 X Y EXAMPLE #2: Class of 22 2 XX 2 X* Y that you go through the power point

Set up the first Generation poster- ‘Generation 0’ with the post-its in ‘bar graph’ position, like so (excepting the one^ 9 XX^ 9 X** Y

BACKGROUND FOR EDUCATORS Many of us might take our color vision for granted, but human vision has changed dramatically over the course of evolutionary time. In fact, many species have gone through shifts in the range of their color perception, and many of them see the world very differently than humans. Whales and many other marine mammals don’t see ‘color’ the way the human eye does. They are effectively monochromatic, much like black and white television. Honeybees don’t perceive red/green the way humans do, but they can detect UV light. Most placental mammals, including many of our pets, are dichromatic, or what we would refer to as colorblind. Not so long ago, so were we. Where does color vision ‘live’ in our DNA? How is it passed along? There are three genes for human trichromatic vision, and they code for Red/Green/Blue or RGB. are physically located on the same chromosomes that determine sex in humans. Specifically, they are on the ‘X’ chromosome, not the ‘Y’chromosome. They are dominant, although there is no corresponding recessive allele, meaning that the gene for seeing a particular color doesn’t have a recessive counterpart.

If you have a functional copy of a gene and express it, you will be sensitive to that wavelength of light and ‘see’ that color. If the gene is missing or damaged, you will not ‘see’ that color of light. Since females (XX) have two X chromosomes, there are two chances to get a working copy of a gene. Males (XY) have only one and so only have one chance for a working copy. Males therefore have a much higher incidence of color blindness than females. In this simulation, we will simulate how these genes and chromosomes are passed from generation to generation in a small population. At a certain point, we will introduce selective pressures (in the form of attributes of the physical environment) that will selectively kill off certain members of the population. They will be replaced by the offspring of surviving members of the population, and gradually we should see the make-up and proportions of the gene pool change. However, like in the real world, some of this is due to chance— anything could happen!

Color Vision Genetics Evolution Simulation Next Generation Science Standards Developing and using models 6-8: simple systems with uncertain and less predictable factors 6-8: predict and/or describe phenomena 9-12: (including mathematical and computational) to generate data to support explanations, predict phenomena, analyze systems, and/or solve problems Science and Engineering Practices (^) Develop and/or use a model toUse and/or develop a model of Develop and/or use a model (^) Middle school: LSI.B: Growth and Development of Organisms: characteristic behaviors that increase the odds of reproduction. LS2.A: Interdependent Relationships in Ecosystems: of organisms, are dependent on their environmental interactions with living things and non-living factors. LS3.A: Inheritance of Traits: located in the chromosomes of cells, with each chromosome pair containing two Disciplinary Core Ideas Organisms, and populations Animals engage in Genes are Crosscutting Concepts variants of each of many distinct genes. Each distinct gene chiefly controls the production of specific proteins, which in turn affects the traits of the individual. Changes (mutations) to genes can result in changes to proteins, which can affect the structures and functions of the organism and thereby change traits High school: LS2.A: Interdependent Relationships in Ecosystems: capacities, which are limits to the numbers of organisms and populations they can support. These limits result from such factors as the availability of living and non-living resources and from such challenges as predation, competition, and disease. LS4.B: Natural Selection: selection occurs only if there is both (1) variation in the genetic information between organisms in a population and (2) variation in the expression of Ecosystems have carrying Natural that genetic information—that is, trait variation—that leads to differences in performance among individuals. The traits that positively affect survival are more likely to be reproduced and thus are more common in the population.

Cause and effect 6-8: be used to predict phenomena in natural or designed systems. 6 - 8: one cause, and some cause and effect relationships in systems can only be described using probability. 9-12: be suggested and predicted for complex natural and human designed systems by examining what is known about smaller scale mechanisms within the system. Cause and effect relationships may Cause and effect relationships canPhenomena may have more than

Simulating Color Vision Genetics Evolution: Teaching Natural Selection, Lecture notes of Genetics

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Download Simulating Color Vision Genetics Evolution: Teaching Natural Selection and more Lecture notes Genetics in PDF only on Docsity!

GRADE LEVEL SUBJECTS DURATION SETTING