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Jack Harlan

Jack Harlan is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Jack Harlan rather than just read about it. In short: Jack Rodney Harlan (June 7, 1917 – August 26, 1998) was an American botanist, agronomist, plant collector, and campaigner for crop plant biodiversity conservation. Early life Born in Washington, DC, Jack Harlan was the son of Harry Harlan, a plant breeder who worked on barley at the US Department of Agriculture (USDA), and who travelled around the world on seed collecting expeditions in search of new genetic materia…

Key takeaways

  • Jack Harlan belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Jack Harlan to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Jack Harlan from memory before moving on to harder problems.

Reference excerpt

Jack Rodney Harlan (June 7, 1917 – August 26, 1998) was an American botanist, agronomist, plant collector, and campaigner for crop plant biodiversity conservation.

Early life Born in Washington, DC, Jack Harlan was the son of Harry Harlan, a plant breeder who worked on barley at the US Department of Agriculture (USDA), and who travelled around the world on seed collecting expeditions in search of new genetic material for use the USDA's crop breeding programs. Harry Harlan was a friend of the famous Russian plant breeding expert Nikolai Vavilov, and at the age of fifteen Jack Harlan met Vavilov when the latter stayed at the Harlan house during an international conference. This meeting inspired Jack to become a plant collector himself, and plans were made for him to travel to Russia after finishing his undergraduate degree to work with Vavilov. However the trip was cancelled as a result of Vavilov's deteriorating relationship with the Soviet authorities.

University study and career Harlan earned a B.S. from George Washington University in 1938. He went on to study under the famous botanist and geneticist G. Ledyard Stebbins at the University of California, where he received a Ph.D. in genetics in 1942. From 1942 to 1951 he worked at the U.S. Department of Agriculture, where he worked on breeding forage crops and improving the grazing quality of rangelands in Oklahoma. In 1951 Harlan became a university lecturer and researcher, working first as a professor of agronomy at Oklahoma State University at Stillwater, Oklahoma, where he refused to sign an oath of loyalty, and later as a professor of plant genetics at the University of Illinois Urbana-Champaign. He co-founded the Crop Evolution Laboratory there in 1966. He moved to New Orleans, Louisiana in the 1980s and served as an adjunct professor at Tulane University. Harlan published a variety of papers in the area of crop biodiversity, and publicized his concerns that modern agricultural practices were contributing to the extinction of older, traditional varieties of crops.

Plant collecting As a scientist Harlan had two complementary research interests; the practical work of breeding economically important crops for desirable traits such as disease resistance or higher yield, and archaeobotany, the archeological study of the origins of crop domestication. Over the course of his career he carried out over forty plant- and seed-collecting expeditions to locations all over the world. Many of these expeditions were funded by the USDA, and the samples he brought back were added to USDA seed collections. Harlan was famous for the quality and quantity of the seed collections he brought back. Some of Harlan's collected seeds came to be used successfully in official USDA breeding programs. For example, in 1948 Harlan and his colleague Osman Tosun collected some wheat grains in a field in eastern Turkey (it was later discovered that the grains may actually have come from Iraq, having been brought to Turkey by recent immigrants). The sample was added to the USDA's seed bank as PI 178383. Fifteen years later in the early 1960s there was a severe epidemic of stripe rust, and hundreds of seed collections were tested for resistance to the rust. PI 178383 turned out to be resistant, not only to the stripe rust, but to several other wheat diseases as well, and it was added to breeding programs to produce new, resistant varieties, which were widely grown in America's northwestern states.

Views on the origins of crop plant genetic diversity Harlan agreed broadly with Vavilov's idea that just a few geographical locations are crucial for generating much of the biodiversity on which plant breeders depend. However Harlan preferred the term center of diversity to Vavilov's term center of origin, because while the centers of crop diversity are known and mapped, the origins of crops cannot be definitely pinned down. In The Living Fields: Our Agricultural Heritage he wrote:

First, we will not and cannot find a time or place where agriculture originated. We will not and cannot because it did not happen that way. Agriculture is not the result of a happening, an idea, an invention, discovery or instruction by a god or goddess. It emerged as a result of long periods of intimate coevolution between plants and man... The coevolution took place over millennia and over vast regions measured in terms of thousands of kilometers. There were many independent tentatives in many locations that fused over time to produce effective food production systems. Origins are diffuse in both time and space.

Awards John Simon Guggenheim Memorial Fellowship (1959) American Grassland Council Merit Award (1962) Frank N. Meyer Memorial Medal for Plant Genetic Resources, awarded by the Crop Science Society of America (1971) International Service in Agronomy Award (1976) Distinguished Botanist Award, awarded by the Society for Economic Botany (1986) Vavilov Medal, awarded during the Vavilov Centennial Celebration in Moscow and St. Petersburg (1987)

Publications

as author 1956, Theory and Dynamics of Grassland Agriculture, Jack R. Harlan, Van Nostrand 1976, Crops and Man, Jack R. Harlan, American Society of Agronomy 1995, The Living Fields: Our Agricultural Heritage, Jack R. Harlan, Cambridge University Press

as editor 1976, Origins of African Plant Domestication, edited with Jan M. J. De Wet and Ann B. L. Stemler, Mouton Publishers Origins of African Plant Domestication. Walter de Gruyter. 24 June 2011. ISBN 978-3-11-080637-3; pbk reprint{{cite book}}: CS1 maint: postscript (link)

Footnotes

External links Theodore Hymowitz, "Jack Rodney Harlan", Biographical Memoirs of the National Academy of Sciences (2003)

Worked examples

Example 1 — a first encounter with Jack Harlan

Start with the simplest possible case. Write down what Jack Harlan claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Jack Harlan before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Jack Harlan ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Jack Harlan

In research
Jack Harlan appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Jack Harlan in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Jack Harlan is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1917 births, 1998 deaths, 20th-century American agronomists, so understanding it makes those chapters shorter.
In everyday life
Look for Jack Harlan outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Jack Harlan in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Jack Harlan means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Jack Harlan out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jack Harlan in simple terms?

Jack Rodney Harlan (June 7, 1917 – August 26, 1998) was an American botanist, agronomist, plant collector, and campaigner for crop plant biodiversity conservation. Early life Born in Washington, DC, Jack Harlan was the son of Harry Harlan, a plant breeder who worked on barley at the US Department o…

Why does Jack Harlan matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Jack Harlan?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Jack Harlan.

Tags

  • 1917 births
  • 1998 deaths
  • 20th-century American agronomists
  • 20th-century American botanists

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