Read Online The Darwin Awards Next Evolution: Chlorinating the Gene Pool by Wendy Northcutt - Free Book Online Page A
Authors: Wendy Northcutt
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resonance to the needs and desires of their local animal partners. By the Late Cretaceous, twenty million years later, the luxuriant emerald-green world of the dinosaurs had been adorned with bright blossoms and sweet scents.
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Research shows that flower fragrances travel only one-third as far today as they did in less-polluted years.
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After dinosaurs disappeared sixty-five million years ago, plant-munching mammals rose to prominence, and flowering plants came up with their next smash hits: fruits and grasses. Citrus fruits in particular, of the group Rutaceae , are a favorite of tree-dwelling animals. The animals eat the fruity prize; the seeds are safely transported all over the jungle and then deposited in a steaming pile of rich animal fertilizer. Liliopsida, an angiosperm better known as grass, appears widely in the fossil record in the Eocene. By thirty million years ago grasses dominated the flat savanna and provided food for the largest mammals ever to walk the earth.
Over the next twenty-five million years a few of these hardy flowering grasses evolved into the forerunners of modern cereal grains: wheat, corn, and rice. Those three grains account for over half the calories in the modern human diet. A whopping five trillion calories of cereal are consumed each day, and two trillion more in the form of tubers, vegetables and vegetable oil, fruits, syrups, and other sugars made from flowering plants. Added to that, every pound of meat we eat conservatively represents thousands of calories of commercial cereals and wild grasses.
The Plant Kingdom could not have supported the kinds and numbers of animals it does today before the advent of flowering plants. And even with the sweet fruits and toothsome grains they offer, artificial selection was required, operating over millennia on hundreds of angiosperm species, so that humans can harvest the amount of food we currently eat.
Quite literally, human beings are flower-powered.
Teosinte (top) began as a single stalk of kernels, each enclosed in its own individual husk. Over time artificial selection produced strains with large kernels and softer husks, until we can recognize the first corncobs (center). Modern corn (bottom) is a mutant version so freakishly large it cannot survive or reproduce without human cultivation and care. Illustration by Karen Wehrstein.
How is all this ancient flowery history known or suspected? Some is educated guesswork. But much of it falls under the purview of paleobotany and palynology, the study of ancient pollen. Most small plants don’t lend themselves to fossilization. But plant pollen is tough and fossilizes well. Particular groups of plants can often be distinguished by their pollen. Thanks to the painstaking dedication of thousands of botanists over the years, we have developed a robust database of ancient pollens, tracing the evolutionary radiation of angiosperms onto the global stage.
Of course, the flowering plants could never fully trust their new animal partners. Given half a chance the animals would gobble down the whole plant: fruit, nut, flower, leaf, stem, and root. Evolution quickly produced critters that did exactly that. The plants responded by incorporating substances that give the offending critter a stomachache or worse if it eats the wrong part at the wrong time.
Many of our early medicines and modern drugs come from such defenses. The plant chemicals are bioactive by definition, because they are meant to affect the biology of the animal that eats them. Quinine from tree bark, caffeine from the coffee bean, narcotic painkillers from the opium poppy, and aspirin from the willow tree are substances that don’t pose quite as much danger to us as they do to insects and their ilk. Unlike the bugs’, our bodies come complete with sophisticated, factory-installed detoxification systems. In fact, for humans, the effects of some of those natural insecticides are downright addictive.
Which brings us back to that
----
Research shows that flower fragrances travel only one-third as far today as they did in less-polluted years.
----
After dinosaurs disappeared sixty-five million years ago, plant-munching mammals rose to prominence, and flowering plants came up with their next smash hits: fruits and grasses. Citrus fruits in particular, of the group Rutaceae , are a favorite of tree-dwelling animals. The animals eat the fruity prize; the seeds are safely transported all over the jungle and then deposited in a steaming pile of rich animal fertilizer. Liliopsida, an angiosperm better known as grass, appears widely in the fossil record in the Eocene. By thirty million years ago grasses dominated the flat savanna and provided food for the largest mammals ever to walk the earth.
Over the next twenty-five million years a few of these hardy flowering grasses evolved into the forerunners of modern cereal grains: wheat, corn, and rice. Those three grains account for over half the calories in the modern human diet. A whopping five trillion calories of cereal are consumed each day, and two trillion more in the form of tubers, vegetables and vegetable oil, fruits, syrups, and other sugars made from flowering plants. Added to that, every pound of meat we eat conservatively represents thousands of calories of commercial cereals and wild grasses.
The Plant Kingdom could not have supported the kinds and numbers of animals it does today before the advent of flowering plants. And even with the sweet fruits and toothsome grains they offer, artificial selection was required, operating over millennia on hundreds of angiosperm species, so that humans can harvest the amount of food we currently eat.
Quite literally, human beings are flower-powered.
Teosinte (top) began as a single stalk of kernels, each enclosed in its own individual husk. Over time artificial selection produced strains with large kernels and softer husks, until we can recognize the first corncobs (center). Modern corn (bottom) is a mutant version so freakishly large it cannot survive or reproduce without human cultivation and care. Illustration by Karen Wehrstein.
How is all this ancient flowery history known or suspected? Some is educated guesswork. But much of it falls under the purview of paleobotany and palynology, the study of ancient pollen. Most small plants don’t lend themselves to fossilization. But plant pollen is tough and fossilizes well. Particular groups of plants can often be distinguished by their pollen. Thanks to the painstaking dedication of thousands of botanists over the years, we have developed a robust database of ancient pollens, tracing the evolutionary radiation of angiosperms onto the global stage.
Of course, the flowering plants could never fully trust their new animal partners. Given half a chance the animals would gobble down the whole plant: fruit, nut, flower, leaf, stem, and root. Evolution quickly produced critters that did exactly that. The plants responded by incorporating substances that give the offending critter a stomachache or worse if it eats the wrong part at the wrong time.
Many of our early medicines and modern drugs come from such defenses. The plant chemicals are bioactive by definition, because they are meant to affect the biology of the animal that eats them. Quinine from tree bark, caffeine from the coffee bean, narcotic painkillers from the opium poppy, and aspirin from the willow tree are substances that don’t pose quite as much danger to us as they do to insects and their ilk. Unlike the bugs’, our bodies come complete with sophisticated, factory-installed detoxification systems. In fact, for humans, the effects of some of those natural insecticides are downright addictive.
Which brings us back to that
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