BI111 Lecture Notes - Monocotyledon, Tracheid, Motility
Document Summary
Dramatically influence both terrestrial, aquatic, and atmospheric conditions. 300,000 living species 10 phyla important to today"s ecological processes carbon, water, nitrogen, etc. primary producers in terrestrial food web. Land plants first evolved in the ordovician periods (488. 3 +- 1. 7 to 443. 7 +_ 1. 5 million years ago) Early to middle ordocvician mild climate with moist atmosphere. Marines and freshwater organism had dramatically changed atmosphere (cyanobacteria use water as a reducing agent, producing atmospheric o2 as a byproduct), but co2 levels were still. Ancestor was likely a charophyte (a type of green algae, aka stonewort) Storage of products of photosynthesis as amylose starch. No specialized transport or support structures: body supported by water, where nutrients obtained. Early plants has no control over water content, were restricted to moist areas. Poikiohydric (poilio = variable; hydric = relating to water) Like algae, water essential for reproduction (motile gametes) Present in all bryophytes (mosses, liverworts and hornworts)
