BIOL 1902 Lecture 5: Lecture 5
31 Jan 2019
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Trees and other woody plants: hard coats physical protection around seeds. Producing objects that pierce: spines modified leaves, prickles modified epidermal outgrowths, like hairs, blackberries and raspberries have lots of prickles, thornes modified branches, hawthorn"s. Plants have evolved ways of modifying different parts of their structure to be used for defences elements that have the intent to cause pain. Plants can also have softer elements: trichomes modified hairs. Create physical barrier for smaller animals like insects who may want to eat them have trouble walking through it: example: mullein, glandular trichomes physical + chemical combination not always poisonous, example: stinging nettles. Have little trichomes and when you touch them, they break your skin and inject some chemicals in that really burn. Trichomes can be just soft and be a physical barrier to insect or have glands on them and be a chemical defence to larger animals.
