BIOL 111 Lecture Notes - Lecture 15: Rhyniopsida, Gametophyte, Sporophyte

• School: McGill University
• Department: Biology
• Course: BIOL 111
• Professor: Andrew Hendry

Document Summary

Taller ---- vascular tissue: functions: transport sugars (from the top), water, nutrient (from the bottom, support (as they get taller, they have to support their framework) Nonvascular plants have conducting cells but no secondary thickening ---- some conductance but no support (that"s why some of these plants remaining small) Earliest vascular plants: cooksoniods, rhyniophytes: thickened conducting cells, some branches but no leaves (used photosynthetic stems) or roots (used rhizoids) Increasingly effective vascular tissue, from spongy cork-like tissue (s-type) to hollow lignified tubes (p-type) Deeper ---- roots (multiple independent evolutions through devonian ---- evolved bit by bit and simultaneously in different groups: functions, nutrient acquisition, support, communication (network trees together and help them communicate ---- boreal forest) Reproduction ways ---- reduction of gametophyte: comparison, nonvascular plants: have short and small lived sporophyte and depend on gametophyte for nutrition. Gametophyte-dominant life cycle: vascular seedless plants: sporophyte is much longer and longer lived than gametophyte. Extant vascular seedless plants (dominant vegetation in devonian)