Liverworts & Mosses Lecture

Kingdom Plantae Chapter 16, Bryophytes Way Back Machine™: plants live in water. get bored, move to land. Transitions to land 1. Sterile jacket cells around anthoridia(male) and anehegutuo(female) 2. Embryo retained in archegonium(female reproductive structure) 3. Aerial parts of the plant coated with a waxy cuticle 4. Water conducting tissues (big deal) The earliest reasonabley intact fossils of plant-like organisms seem to be about 430 million years old; Silurian. Some evidence points to higher plants up to 450 myo, but this evidence is not clear or accepted. Phylum Hepatophyta Hepato=liver; wort=thing Liverworts 6,000 species thin cell plates can form masses feet across Doctrine of signatures 9th century belief During creation, G-d created everything for human benefit. The doctrine of signatures put forth that He also shaped everything according to its function, i.e. liver-shaped plants are good for your liver. Simplest land plants No cuticle, no water proofing No vascular tissue, can't move water around in the body No stomata, no pores that regulate gas exchange No roots On bottom one'll find Rhizoids, or cellular hairs that attach to whatever its attached to Humans are diploid, produce gametes (haploid) that combine to form a zygote (diploid again). Liverworts are haploid, can form gametesthat immediately form zygotes (sporophyte) what immediately undergoes meiosis and forms the haploid adult (gametophyte). We say that the gametophyte is the dominant generation. We say that there is an alternation of generations; alternating between the gametophyte and the sporophyte (haploid and diploid).  Genus Marchantia Most common genus When time to produce gametes, grows a palm tree from the cell plate. Hanging under the "leaves" are the gametes. Anchegonium p.350-2 Antheridium Phylum Anthocerophyta Type genus Anthoceros Hornworts Resemble liverworts, but have many characteristics like green algae Each cell, like algae, has one large chloroplast w/ a pytenoid (starch manager) Has a cuticle Has stomata Phylum Bryophyta True Mosses 9,500 species aspect dominant in some northern latitudes, i.e. above the arctic circle Sensitive to sulfer dioxide (car exhaust) Class Bryidae True Mosses Gametophytes have two morphological phases When a spore germenates, it produces a protonema (long branchy thing), looks like green algae, which puts out a bud and quickly produces a leafy upright phase (what you see as moss). Conducting cells move water, called hydroids Conducting cells move nutrients, called leptoids Can grow up to 50 cm Sporophytes stick up from leafy thing, has stalk (seta) and large upper thing with a protective coating called calypta. Calypta pops off when sporophyte grows large enough. Operculum Capsule filled with spores Operculum pops off when ready, revealing the peristone (set of inward facing teethishness), any water makes the peristone react violently, expelling 50 million spores rather quickly Peristone identifys this class Sporophyte entirely dependent on the gametophyte Class Sphagnidae One genus Genus sphagnum Peat Moss 350 species "clearly diverged from main moss evolutionary line long ago" Loaf shaped cell group Peat Bogs formed by... peat moss! 1% of earth's land surface covered by this genus

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