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Sir Frederick Grant Banting was born in Ontario, Canada, in 1891. In 1909, after his education in local primary and secondary schools, he entered the University of Toronto for a ministry degree. After one year, he switched to a medical degree. In 1918, Banting worked as an orthopedic surgeon. After two years, he taught anatomy and physiology at the University of Western Ontario. He also conducted medical research under the supervision of Frederick Robert Miller, a prominent neurophysiologist. Banting was dedicated to teaching. While researching the literature for an upcoming lecture on the pancreas, he became curious about previous work on diabetes and the pancreas. He read that if the pancreatic ducts were damaged but the islets of Langerhans remained intact, no diabetic symptoms developed. Researchers theorized that the islets of Langerhans released a hormone preventing diabetes. Extracting this compound, however, was a problem. Investigators speculated that other pancreatic secretions outside the islets of Langerhans destroyed the mystery hormone during extraction procedures. Researchers discovered that, with blockage of the pancreatic ducts, all regions in the pancreas atrophied except for the islets of Langerhans. Banting had a talent for synthesis. He read about many seemingly unrelated research discoveries about the pancreas and fit the pieces of the diabetes puzzle together. In October, 1920, he designed his famous experiment that increased the lifespan of diabetics. INSET: Sir Frederick Grant Banting.

For many years, ecologists referred to niche in terms of an organism’s place in the food pyramid. The food pyramid is a simplified scheme showing organisms’ interactions with one another while obtaining nourishment. The food pyramid is represented visually as a triangle, often with four horizontal divisions, each division being a different trophic level.

The idea of the niche probably had its first roots in ecology in 1910. At that time, Roswell Johnson wrote that different species utilize different niches in the environment. He theorized that individuals of a particular species are only in certain places because of food supply and environmental factors that limit their distribution in an area. Later, in 1924, Joseph Grinnell developed his concept of niche that centered on an organism’s distribution having limits set on it by climatic and physical barriers. At the same time, Charles Elton was defining his own idea of niche. His description of niche involved the way an organism makes its living—in particular, how it gathers food.

Effects of overgrazing occur where there are more grazing animals than the land and vegetation can support. Overgrazing has negatively affected many regions globally, including large portions of sub-Saharan Africa, the southwestern United States, and the Indian subcontinent in Asia. Areas that have been severely damaged by overgrazing may experience desertification, invasion by nonnative plant species, and an increase in endangered plant and animal species.