MUSHROOMS AND TOADSTOOLS
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We normally think of a mushroom or toadstool as the whole of a fungus, because this is usually all we can see. However, these are only the reproductive organs, where spores are produced. The mycelium of the fungus is usually hidden below ground or within rotting materials, where it is moist and where the hyphae can digest the surrounding tissue and absorb the nutrients that are released. The reproductive structures have to be large enough so that the wind can carry the spores away to other places, and tough enough to survive the drying conditions of the air until the spores have been dispersed.
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● SCIENCE IN CONTEXT
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▷▷Fig. 1.8 A mushroom or toadstool is only the visible part of this fungus. The rest of the structure is hidden from view.
QUESTIONS
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1. Which characteristics do fungi share with a) plants and
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b) animals?
2. Describe what is meant by saprotrophic nutrition and how
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it differs from the way animals get their nutrition.
3. Most people think of toadstools and mushrooms as the main
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part of fungi. Explain why this is incorrect.
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PROTOCTISTS Protoctists are also single-celled microscopic organisms, usually much larger than bacteria. Their cells contain a nucleus and many have features of animal cells or plant cells. One example is Amoeba, which looks like an animal cell and is found in ponds and feeds on other microscopic organisms. Other protoctists, such as Chlorella, look more like plant cells because they contain chloroplasts and so can photosynthesise. A few protoctists are pathogens, such as Plasmodium, the organism that causes the disease malaria in humans.
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