Looking Back at Bio 115 The Organism as a Unit of Life Cellular Structure (cell = unit of life)…one or many! Metabolism = Homeostasis (PSN, Resp, N 2 fix, ferment, etc.) Growth = irreversible change in size Reproduction…failure = extinction Acclimatization-short term responses = behavior Adaptation-long term responses = evolution
Shifting Kingdoms Bacteria Archaebacteria Archezoans Euglenoids Chrysophytes Green Algae Brown Algae Red algae Slime Molds True Fungi Bryophytes Tracheophytes Protozoans Myxozoans Multicellular Animals Lumpers Splitters Plantae
How Many Kingdoms? Multicellular Animals MyxozoansProtozoans Tracheophytes Bryophytes True Fungi Slime Molds Red algae Brown Algae Green Algae Chrysophytes EuglenoidsArchezoans Archaebacteria Bacteria Original Cell Extant Extinct Long Time with Prokaryotes only
Bryophytes Although they have no true xylem or phloem and do reproduce sexually with spores…. Never any doubt about their status as plants Cellulose walls glued together with pectin Chlorophyll a and b, xanthophylls, carotenoids Store starch Standard plant chloroplasts, mitochondria, golgi, etc. Diplohaplontic (sporic) life history Oogamous gametes Do have conductive tissue: hydroids and leptoids 500 species Two Major Classes: 1.Hepaticopsida (liverworts) 2.Musci (mosses)
Marchantia polymorpha Thallose liverwort Haploid (1N) gametophyte thallus has photosynthetic chambers with chimney cells for gas exchange. The thallus grows in notches at thallus ends. In some seasons produce gemmae cups (cupules) that contain tiny gemmae for asexual reproduction of gametophyte. Beneath thallus, uniseriate rhizoids anchor to substrate.
Generalized Sporic (diplohaplontic) Life Cycle SYNGAMY MEIOSIS zygote SporophyteGametophyte sporangium sporocyte spores gametangia gametes germination mitosis differentiation mitosis germination mitosis differentiation mitosis 1N 2N differentiation In the gametic (diplontic) shortcut the product of meiosis becomes a gamete (no multicellular haploid) In the zygotic (haplontic) shortcut, the zygote undergoes meiosis (no multicellular diploid)