Ch 29 Plant Diversity 1Algal Ancestry- Plants and chlorophytes share many common featureso They are multicellular and photosynthesizeo Chloroplasts with chlorophyll a and bo Cell walls with celluloseo Storage molecule is starch- Charophytes are the closest algal relatives to plantso Several cell-level synapomorphies (shared derived characteristics) Peroxisomes, cytokinesis, see book- Many charophytes live in ponds that dry outo Zygotes survive in the dry air by a protected coat of sporopollenin (29.3)o Similar conditions may have led to the first plants- There is one common ancestor for all plantso It was most similar to today’s bryophyte and arose around 475 myao Plant lineages are marked by key adaptations to land lifeAdaptations to land life- Alternation of Generationso Found in some algae, but not in charophyteso It multiplies the number of unique offspring per fertilization- Walled haploid sporeso Allows for dispersal through airo Sporopellenin prevents desiccationo Made with in the multicellular sporangia- Multicellular gametangiao Protecting sperm with in the antheridiumo Protecting egg with in the archegonium- Embryos enclosed with in the female gametophyteo Nourished through placental transfer cells- Cuticleo A waxy coat around the leaves that stops desiccationo Stomata (present in most plants) are pores needed to allow for gas exchange - Apical Meristemso Meristems just keep dividingo Continual growth toward resources (directional growth)- Mycorrhizaeo Mutualism with fungi that helps with water and mineral absorptiono Date back to early land plants (before roots)- Secondary compoundso Chemicals that protect plants from competitors, herbivores and parasiteso Caffeine, latex rubber, tanninsDiversification of PlantsKingdom Plantae is monophyletic- Major lineages linked to key adaptationsTable 29.1Bryophytes- Non-vascular Plants- Liverwarts= Hepatophyta- Mosses= Bryophyta- Hornworts= Anthoerophyta- Common featureso Haploid gametophyte is dominant, independent form in the life cycle Lacks supportive and vascular tissue Most are small, low growing, in moist areaso Body size restricted because they are dependent on diffusiono Very thin bodyo Have rhizoids for attachment and anchoring, but they are not true rootso Diploid sporophyte depends on gametophyte for food and water Develops from the zygote within the archegonium Sporangium makes haploid spores- Moss life cycleo Spores (n) are produced and dispersed in the air, need water when they lando If they find water, the start to grown and photosynthesize, a bud becomes a full male or female gametophyteo Gametophytes make gametes in the archegonium or antheridiumo Sperm swims to the egg for fertilizationo Goes through mitosis to form a dependent sporophyteo Sporophyte goes through meiosis to make spores- Ecological Importanceo Major producers in cold, high regions or places with bad soilo Sphagnum (peat moss) 29.11- bird migration and wetlands, fuel source, gardeningEarly Seedless Vascular PlantsEvolution of a larger sporophyte- Dichotomous branching led to multiple sporangia- More spores lead to more offspring- Independence of the gametophyte began with photosynthesis in stems- Vascular tissue supports taller stemso Xylem carries water and minerals Tracheido (strengthened by lignin) in most vascular plants gives lots of supporto Phloem carries sugar and other products of photosynthesis- Roots evolved from underground stemso Anchor larger plantso Absorb water and mineralso Mycorrihzae- Taller growth improves access to light- Evolution of leaveso Microphylls first= single vein Only present in lycophytes todayo Magaphylls later ex- fern Larger with branched veins In pterophytes and seed plantso Sporophylls are leaves that bear sporangia Sori are a cluster of sporangia Strobius are on lycophytes and are cone like groups of sprophylso Sparophytes can be huge Tree size in the Carboniferious swampsPhylum lycophyta- Relicit groupo Closest group to the ancestral vascular plantso All very smallo Have microphyllys and strobili (cone like structures)o Include club mosses, quillwort, and spike mosseso Little ecological importancePhylum pterophyta- Whisk fernso Dichotomous branchingo No true leaves or roots- Horse tailso Jjointed stems and tiny leaves, stobili- Fernso Most widespread and diverse pterophyteso Mostly understory/ epiphytes (grow on something but not a parasite)o There are some tree sized ones todayo Have large megaphyllso Sporophylls with sori on the undersidesThe fern life cycle is almost the same as the moss