Sacramento State professor Jamie Kneitel explains how plants have shaped civilization during his presentation at the River Valley Garden Club's Oct. 27 meeting.

RANCHO MURIETA, CA (MPG) - How do you condense 15 weeks of college instruction and 25 lectures into a 45-minute presentation?

That was the challenge facing Sacramento State professor Jamie Kneitel when he spoke to the River Valley Garden Club on Oct. 27 about the role plants have played in the development of civilization.

Kneitel, chair of the university's Department of Environmental Studies, teaches a course called "Plants & Civilization," covering subjects ranging from the origins of agriculture and the domestication of crops to medicinal plants, spices and the importance of biodiversity.

A map illustrates the geographic origins of familiar crops, including corn from Mexico, potatoes from South America and rice from Asia.

Faced with the challenge of squeezing the course into a single presentation, Kneitel told club members he decided to "cherry pick" topics and offer what he described as a "greatest hits" version of the course.

The invitation grew out of the club's support for an apothecary garden that Kneitel and his students are developing on the Sacramento State campus.

Kneitel attended the club's September meeting to accept a $500 grant to help pay for the garden, which will feature plants traditionally used for medicinal purposes. He explained that students in his course are required to spend five hours working in a garden during the semester. The apothecary garden is one of several campus gardens where they can fulfill that requirement.

Kneitel told members he had already purchased plants for the garden, including lavender, rosemary, milkweed, native sages and poppies. Students were scheduled to begin planting later that week, with additional planting continuing through the semester.

A colorful slide illustrates the many benefits of plants, from providing food and supporting human health to maintaining ecosystems and combating climate change.

After Kneitel accepted the grant, club members expressed interest in his course and asked whether he would return to give a presentation about plants and civilization. He agreed, although he subsequently realized how difficult it would be to condense the material.

Kneitel, who also spoke to the club last year about vernal pools, began his presentation by asking members how plants have affected civilization.

One audience member responded that civilization wouldn't exist without them.

"Exactly," Kneitel replied, explaining that plants form the foundation of food webs and made the development of human civilization possible.

The domestication of plants allowed people to produce more food, support larger populations and develop specialized occupations, eventually leading to technological advances.

Kneitel traced the beginnings of agriculture to approximately 12,000 to 15,000 years ago, when humans began cultivating plants rather than relying entirely on hunting and gathering.

Although thousands of plant species have been grown for food throughout history, relatively few account for most of the food produced commercially today.

He also explained how different regions of the world became centers of crop domestication. Corn and chili peppers originated in Mexico, while wheat and barley were domesticated in the Middle East and Mediterranean regions. Rice and soybeans were among the important crops developed in Asia.

One example of the ingenuity of generations of farmers is the wild mustard plant, from which humans developed various vegetables, including broccoli, cauliflower, cabbage, kale, and Brussels sprouts, by selecting for desirable characteristics.

Kneitel also described how humans gradually transformed corn from a plant producing small ears into the much larger varieties grown today.

Another subject was the importance of combining grains and legumes in human diets. The two provide complementary amino acids, helping supply the protein people need.

Six familiar vegetables are cultivated varieties of the same wild mustard species, developed through centuries of selective breeding.

Beyond food, Kneitel discussed the many chemical compounds plants produce to defend themselves against insects, disease and environmental stresses. Humans have found uses for these compounds in medicines, fragrances and spices.

He cited willow bark, long used to relieve pain and fever, as an example of a plant that contributed to the development of modern medicine. Other plants have yielded compounds used in cancer treatments.

Kneitel also drew connections between California's Mediterranean climate and the aromatic plants that thrive in similar climates worldwide. Rosemary, sage, oregano and other herbs produce oils that help them cope with environmental stresses while providing flavors and fragrances valued by humans.

One of his more unusual examples involved milkweed, best known as a host plant for monarch butterflies. During World War II, when supplies of traditional life jacket filling materials were disrupted, the silky fibers from milkweed seed pods were collected for use as flotation material.

Throughout the presentation, Kneitel returned to the ingenuity of people who discovered how to cultivate and use plants over thousands of years.

He said teaching the course has given him a greater appreciation for the generations of people whose discoveries and agricultural practices have shaped modern life.

He concluded by emphasizing the importance of preserving biodiversity, not only because plants support ecosystems but also because scientists continue to discover new medicinal compounds and other useful properties.

"The maintenance of biodiversity and sustainability of these ecosystems are really critical for our own life and our own sustainability and future," he said.

Kneitel offered to return for a more detailed presentation on individual subjects from his course, noting that topics such as spices, coffee, tea and legumes could each fill an entire lecture.