These brief video segments can be used alone or in combination, to introduce a topic or to spark discussion among your students. The video segments can be adapted for any grade level – suggested focus questions are provided. Stream the video segments from the playlist below, or scroll to the bottom of the page to find downloadable QuickTime versions of the videos. These videos are also used in the lesson plan The Perfect Cow? (grades 9-12).
Cattle originally evolved over millions of years through a process of natural selection-also known as “survival of the fittest”-which made them adaptable to a wide variety of environments, including most of those inhabited by another highly adaptable species: humans. Once humans discovered how to domesticate cattle about 4,000 years ago, they began to selectively, or “artificially,” breed them for specific desired traits like meat and milk production. This resulted in animals fit less for survival in the wild than the satisfaction of human needs, but in purely genetic terms, the arrangement has proven highly successful for cattle. Cattle now thrive throughout the world in over 800 different breeds, each more or less successfully adapted to their environment and the needs of their human caretakers.
The excerpted clips from the NATURE episode “Holy Cow!” illustrate some of the naturally evolved and artificially selected attributes of cattle.
Suggested Focus Questions:
Clip 1: A Cow’s Digestive System
- What role do microbes serve in a cow’s rumen?
- Does this clip illustrate naturally or artificially selected attributes?
- Why would a cow’s ability to eat grass make it ideal for human domestication?
Clip 2: Desirable Breeding Traits in Cattle
- How many different breeds of cattle have humans created?
- Would the qualities that make good beef cattle help them survive in the wild?
- Besides milk and meat production, what other traits might humans wish to breed in cattle?
Clip 3: Different Breeds of Cattle
- What might indicate that a cattle breed is adapted to cold climates like Scotland?
- What do the different breed names refer to?
- Why might “adaptability” be a desirable trait in a specific breed?
Downloadable QuickTime versions of the video segments:
(Note: To downoad a video, right-click on the video title and click “Save Link As…” or “Save Target As…” On a Mac, press the CTRL key and simultaneously click the mouse, then save the link.)
Clip 1, “A Cow’s Digestive System”
Clip 3, “Different Breeds of Cattle”