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The bizarre and incredible world of plants

The Bizarre and Incredible World of Plants
by Wolfgang Stuppy; Robert Kesseler; Madeline Harfley
Excerpt THE INCREDIBLE LIFE OF PLANTS Plants are truly amazing because, unlike animals, they have the remarkable ability to use sunlight to make sugar from just water and carbon dioxide ( photosynthesis ). In doing so, they not only produce their own food but also feed -- either directly or indirectly -- all life on Earth. Furthermore, as a by-product of photosynthesis, they produce the oxygen in our atmosphere. Quite simply, without plants we would not be able to breathe or eat. Rice alone is the staple food of over half of the Earth's population; and there are many other cereals, as well as pulses and vegetables. Apart from essential nourishment, plants give us delicious treats such as fruits, nuts and precious spices, and useful things like timber, fibres and oils. Plants play an important role in our lives in many different ways but, because they are static and silent, we tend not to consider them as living entities like ourselves. Their completely different texture and appearance, and the fact that they are rooted in the ground and move on a time scale that is far too slow to be noticeable to the human eye seem to render any comparison with animals and humans absurd, but this is far from true. Not only do plants have lives, just as animals do but, over several hundred million years of evolution, like animals, they have developed very complex lives, often in mutual response to animal evolution. Despite their differences, plants and animals share the same purpose in life: survival to achieve sexual reproduction and ensure the continuity of the species. However, plants, unlike animals, have a back up strategy: in the event of unrequited love they can often reproduce asexually. Nevertheless, sexual reproduction is critically important, and this is why: a new animal begins life as the result of the union of a sperm from the father and an egg cell from the mother. In the process, each parent contributes one set of chromosomes . The same happens in plants when a male sperm and a female egg meet. In all living beings, the chromosomes contain the genes that determine every characteristic of the organism. By mixing together the chromosomes and thus the genetic traits of the parents, an offspring with a slightly different, perhaps even better combination of characteristics is created. Furthermore it is sexual reproduction that provides the basis for evolution by natural selection. Many plants can reproduce vegetatively, for example the runners of strawberries, but the new individuals are genetically identical clones of the mother plant and this is why most plants typically reproduce sexually. That plants have a sex life still comes as a surprise to many people although we are familiar with the activities that surround their sexual activity. Perhaps without realising what is going on, we enjoy watching some of the ways in which plants conduct their most private affairs: flowers are pleasing to the eye and and often to the nose as well, and the fruits that follow bring pleasure to our palate. However, from a scientific point of view, flowers are simply a display of often colourful, insect-attracting petals surrounding the central male and female genitalia -- the stamens and the pistil . After sexual union, as the flowers fade, fruits develop from the female ovaries at the base of the pistil. Fruits are swollen female organs which carry the tiny plant embryos, each packaged within a seed coat . After the seed ripens and leaves the parent plant the embryo inside the seed coat will germinate and, leaving the safety of the seed coat, develops into a seedling that will give rise to a new plant carrying the full chromosome complement from both parents. Floral sexual organs, and the fruits and seeds which develop after sexual union bear an enormous responsibility: flowering, pollination and fruiting are the key events in a plant's life and vital to the survival of the species. It is because of the union of sperm -- carried by pollen grains -- with ovaries of a plant that fruits develop and carry seeds which are the next generation of plants. It is hardly surprising, therefore, that plants have evolved a huge variety of strategies to ensure the success of their progeny. Excerpted from The Bizarre and Incredible World of Plants by Wolfgang Stuppy, Rob Kesseler, Madeline Harley All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.
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The bizarre and incredible world of plants

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