GEO 103 Lecture 25: Mesozoic Era
19 Apr 2017
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Document Summary
Ancestors likely type of green algae - no record. Primitive seedless plants such as ferns similar in reproduction, pigmentation and metabolism. Development of lignin and cellulose - provided structural support for plants to have strength. Development of cutin provided protection from desiccation (losing water), oxidation, uv radiation, parasites. Allowed for collection of water and nutrients from soils. Leaves evolved from outgrowths on stem or branches. Likely lived in moist environments such as mud flats. Transition from small bog-dwelling plants in early devonian to forests of large (up to 10m) tree-size plants in late devonian. Evolution of seeds - removed the need to release spores to environment. Removed need to reside only in moist environments. Plants to many different parts of the world. Spores are very fragile and can be destroyed so it only resides in moist environments. Two types of spores - magaspore with female gametes and microspore with male gametes.
