Manipulating Biology: Costs, Benefits and Controversies

Introduction

Exiled and alone, a young female wolf, soon to be expecting a litter of pups, found herself sitting on her hindquarters along the edge of a rocky cliff overlooking a group of humans.  When the humans first arrived, they survived by scavenging kills left behind by her pack.  Now, the humans had built a camp and were cooking red deer over a fire.  She could see that humans lived in a pack too, not much different from her own.  Ever alert yet starving for sustenance and companionship, she cautiously accepted a meat offering left by one of the curious humans.  After that, humans regularly brought her food or she would scavenge the scrap piles on the outskirts of camp.  Her newborn pups also learned to live along the edge of the human encampment.  Winter arrived, and mama and her pups followed the humans as they left for their winter camp in the lowlands.  When the pups grew of age, some of them continued to follow the human group while others left in search of their own wolf families.  Eventually the wolves that remained by the humans grew to trust them, and even hunt alongside them.  Wolves and humans shared the land and the herds together, defended their territory, and embarked on a relationship that would last for the next 30,000 years.¹

The above narrative is one possible example of how dogs came to be. Every dog we know and love today, from the four pound Chihuahua to the massive two hundred pound Great Dane, shares a common ancestor with the Gray Wolf.  Together, you and your students will examine the concepts of natural and artificial selection that led to the practice of domestication.  Our focus will be on dogs as we trace their ancestry from ancient wolves to the hundreds of breeds and mixed-breeds that exist today. Topics will include how dogs came to be domesticated to live in our homes, provide companionship, and assist us as helpers and healers in our communities.  We will examine how humans have historically manipulated biology through selective breeding to produce desirable traits in our canine companions.  We will also consider ethical responsibilities surrounding “negative” traits that inadvertently, or with disregard, seem to be to the detriment of a living creature. 

This unit was developed during the summer of 2018 at the innovative Yale National Initiative, where teachers from around the nation collaborate with each other and Yale professors to intensely study a topic and bring it back to the classroom in the form of a published curriculum unit.  Yale ecology and evolutionary biology professor Paul Turner led a seminar titled “Manipulating Biology: Costs, Benefits and Controversies,” of which I was an eager participant.  I am the STEM lab teacher at a kindergarten to fourth-grade magnet school in urban New Haven.  Each class spends one hour per week with me as they engage in a variety of hands-on science and engineering projects.  Our population of 400 students is about 50% Hispanic, 40% African American, and about 10% either White or Asian American.  Over 90% of our students receive free or reduced lunch services.  Our school is fortunate to have incredibly dedicated teachers and a well-supplied STEM lab, and I am privileged to work with so many remarkable students and their families. 

We discussed a variety of topics related to manipulating biology during our seminar work at Yale.  Much of that discussion involved an emerging genome editing technology known as CRISPR-Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats).  Think Jurassic Park, but with applications in a variety of fields that includes disease control by changing mosquitos so they cannot transmit malaria or dengue virus, or creating designer human babies that have genetic resistances to hereditary ailments.  While fascinating and certainly a relevant topic to the future of biological manipulation, this unit will concentrate on past and current practices that do not involve direct gene editing.  Instead, third grade students will have this topic brought to their academic level as they create a foundation of understanding about how humans have impacted the evolution of Canis lupus familiaris, the dog.  Third grade students are expected to study the basics of inherited traits under the current NGSS (Next Generation Science Standards) guidelines.  While this unit is designed for third grade, the content and activities within are recommended for any grades third and up. 

Before we get to the classroom activities, the following pages will provide a brief overview of natural selection, artificial selection, and domestication.  This is essential background information that has been carefully selected based on my studies and research at Yale University and will help you to be a well-informed teacher prior to teaching this unit.