This lesson asks students to investigate and think carefully about the human role in the domestication and evolution of ancient and modern dog breeds. Students will explore the relationship between wolves and dogs, the reasons why dogs have been bred, and the controversial wolf hybrid breed. They will conclude by writing essays explaining the role of humans in dog evolution, past and present.

Geography, life sciences

Standard 8: "The characteristics and spatial distribution of ecosystems on Earth's surface"

Two to four hours

• Computer with Internet access
• Blank Xpeditions outline maps of the world, one for each student

Students will

• take a quiz about wolves and dogs and discuss the results;
• label maps with the geographical distribution of wolf subspecies and the original locations of dog breeds;
• read and discuss an article about dog domestication;
• read and discuss an article about the controversial wolf hybrid breed; and
• write essays answering questions about what the role of humans has been and should be in dog evolution.

Have students take the online Wolves and Dogs: Fact and Fiction quiz. After they have taken this quiz, ask them to answer these questions in writing or in a class discussion:

• What is the genetic relationship between dogs and wolves? How closely is Canis lupus related to Canis familiaris?
• Approximately how long ago were dogs domesticated?
• Question number five states that there are many dog breeds "because dogs have undergone a number of changes due to natural selection—and have also changed drastically through artificial selection for hair color, size, and temperament." What does this mean? What is the difference between natural and artificial selection?

Give each student a blank world outline map. Ask them to label the approximate locations of the different wolf subspecies. They can find this information at Learn About Wolves.

Have students read the excerpt from the National Geographic Magazine article Wolf to Woof: The Evolution of Dogs. Discuss the two scenarios by which dogs may have become domesticated. Ask them to hypothesize how dogs could have become so different from wolves in terms of their appearance but retained the vast majority of wolves' genetic makeup.

[Note: Feel free to involve students in a more detailed discussion of genetics and heredity, based on what they have already learned in their science classes. One Web site with interesting visuals to illustrate DNA and heredity is DNA From the Beginning.]

As students learned in the Wolves and Dogs quiz, there are several hundred dog breeds in the world today. All of these breeds are members of the species Canis familiaris. Explain that the estimated number of breeds is broad because it's not always easy to determine when a type of dog is actually a separate breed. The American Kennel Club officially recognizes 150 breeds, but many less "officially" distinguishable breeds exist.

Have students go to the Dog Breed Info Center and the American Kennel Club and link to these dog breeds:

• Older breeds: Saluki, Afghan Hound, St. Bernard, Alaskan Malamute, Lhasa Apso
  
  
• Newer breeds: Australian Shepherd, Pembroke Welsh Corgi, Miniature Poodle, Mountain Cur

Ask them to scroll down each page and read about the origins of these breeds. Have them list the countries or regions where these breeds were first developed.

[Note: To shorten the lesson, divide the class into groups and have each group link to one breed. Groups should then share their findings with the class.]

Ask students to label their maps with the locations where these dog breeds originated. They should use different colors or patterns to differentiate between older and newer breeds.

Ask students to look at their maps and consider the ways that human have altered dogs' geographical distribution and genetic makeup. Discuss the reasons people have bred dogs throughout the centuries (e.g., for herding, hunting, and carrying loads in cold weather). Then discuss the reasons people continue to breed dogs today (e.g., for pets, show, and racing).

Have students read the Introduction and Background sections of the Animal Welfare Information Center's Wolf-Dog Hybrid article. List on the board the major issues and questions that this article will address concerning this controversial dog breed.

Divide the class into eight groups, and assign each group one of the following sections of the Wolf-Dog Hybrid article:

1. Physical Characteristics
2. Breeding and Genetics Part 1 (from the first paragraph through the paragraph beginning "This genetic makeup is most often represented as a percentage"—the paragraph right before the picture)
3. Breeding and Genetics Part 2 (from the paragraph beginning "When advertised for sale" through the paragraph beginning "Wolves and dogs each have 78 chromosomes")
4. Breeding and Genetics Part 3 (from the paragraph beginning "Using the pedigree method" through the end of the section)
5. Behavior Part 1 (from the first paragraph through the paragraph beginning "Though animal attacks on humans are often attributed to aggressiveness")
6. Behavior Part 2 (from the paragraph beginning "There are differences in the predatory instincts" through the end of the section)
7. Ownership of Wolf Hybrids
8. Animal Control and Legal Issues

Ask groups to summarize their assigned sections of the Wolf-Dog Hybrid article for the rest of the class, and hold a discussion on the main issues raised in this article. What are the primary differences between wolf and dog genetics and behavior? How do these differences show up in wolf hybrids? Why are there different opinions as to whether wolf hybrids make good pets?

Pose these questions to the class:

• What has been the role of humans in the evolution of dog breeds?
• How much should people get involved with the genetic mixing of dog species and breeds?

Ask students to write essays providing their opinions on these questions. They should address the following points, using information they have learned in this lesson:

• The development of dog breeds from wolves
• The geographical distribution of wolves and dog breeds and the reasons why certain dog breeds were developed in certain locations
• The controversies surrounding wolf hybrids

Have students research the current debate over genetic engineering and cloning, particularly related to dogs. Ask them to prepare written or oral reports that address these questions:

• What is the difference between cloning and breeding?
• Are dogs relatively easy or difficult to clone? Why?
• If you wanted to clone your black Lab, what steps would the scientists have to take?
• What are some of the difficulties that might occur during the cloning process and that might appear in the new clone (the puppy)?
• Do you think it will ever be possible to clone a pet dog? Do you think it will ever be a common practice? Do you think it should be a common practice? Why or why not?

DNA From the Beginning
Dog Breed Information and Breeder Listing
International Wolf Center
National Geographic: Geoguide—Wolves
National Geographic: Wolf to Woof—The Evolution of Dogs
PBS: Wild Wolves
The Wolf-Dog Hybrid: An Overview of a Controversial Animal