CHAPTERS 6 & 7: PROKARYOTES, FUNGI, AND PLANTS Honors Biology 0 PROKARYOTES Lived alone on Earth for over billion years Most numerous and widespread organisms (total biomass of prokaryotes is ten times that of eukaryotes) Live in cold, hot, salty, acidic, and alkaline habitats Some are pathogenic (most are benign or beneficial) Two domains: Bacteria and Archaea Archaea and Eukarya evolved from a common ancestor PROKARYOTES Cell walls maintain shape, provide protection, and prevent lysis in a hypotonic environment Fig. 6.4 Cell wall differences can be distinguished by gram stain Gram-positive have simple walls with a thick layer of peptidoglycan Gram-negative have complex cell walls with less peptidoglycan and an outer membrane of lipids bonded to carbohydrates 3
Chloroplast Red alga PROKARYOTES Use pili to stick to substrate Flagella allow movement response to chemical and physical signals Endospores - thick protective coat that can dehydrate and is tolerant of extreme heat and cold Endotoxins vs. exotoxins Bioremediation Liquid wastes Rotating spray arm Rock bed coated with aerobic bacteria and fungi Outflow Fig. 6.0 4 PROTISTS Obtain nutrition in a variety of ways (autotrophs, heterotrophs, and absorption) Symbiosis - close association between organisms of two or more species Nucleus Chloroplast Green alga Secondary endosymbiosis Remnant of green alga Euglenozoans Cyanobacterium Primary endosymbiosis Autotrophic eukaryotes Heterotrophic eukaryotes Remnant of red alga Heterotrophic eukaryote Nucleus Evolved into chloroplast Dinoflagellates Nucleus Secondary endosymbiosis Apicomplexans Fig. 6. Stramenopiles 5 PROTISTS Euglenozoans - have a crystalline rod of unknown function inside flagella (include heterotrophs, autotrophs, and pathogenic parasites) Fig, 6.5 Dinoflagellates - marine and freshwater phytoplankton Ciliates - use cilia to move and feed Stramenopiles - named for hairy flagellum (usually paired with a smooth flagellum (ex. water molds, diatoms, and brown algae) 6
PROTISTS Amoebas - move and feed by pseudopodia Slime molds Plasmodium - amoebozoan that forms a plasmodium (multinucleate mass of cytoplasm) Cellular - when food is scarce form a sluglike aggregate 7 PROTISTS Red algae - soft-bodied Green algae - include both chlorophytes and charophytes (closest living relatives of land plants) Volvox colonies Chlamydomonas 8 ALGAE LIFE CYCLES Alteration of generations (hapliod gametophyte and diploid sporophyte) 9
MULTICELLULARITY Gamete Unicellular protist Colony Locomotor 3 Foodsynthesizing Early multicellular organism with specialized, interdependent Somatic Later organism that produces gametes Fig. 6. 0 PLANTS AND FUNGI Mycorrhizae - mutually beneficial associations of plant roots and fungi hyphae Fungi enabled plants to colonize land by helping them absorb water and other minerals and plants provided sugars to the fungi TERRESTRIAL PLANTS Defined by: Alteration of haploid and diploid generations Walled spores produced in sporangia Male and female gametangia Multicellular, dependent sporophyte embryos Challenges: Maintaining moisture within Obtaining resources from soil and air Supporting body in air Reproducing and dispersing without water Vascular tissue Leaf Spores Spores Flagellated sperm Alga Flagellated Water supports sperm alga. Whole alga performs photo- Leaf Stem synthesis; absorbs water, Stem CO, and Roots minerals from Fern water. Roots Stomata; roots anchor plants, absorb water; lignified cell Moss walls; vascular tissue; Stomata only on sporophytes; fertilization requires moisture Flagellated primitive roots anchor plants, sperm no lignin; no vascular tissue; fertilization requires moisture Holdfast (anchors alga) Fig. 7.
Fig. 7. & 7.4 MOSSES Nonvascular plant Dominant gametophyte Produces eggs and sperm in gametangia Zygote develops within the gametangium into a mature sporophyte which remains attached to the gametophyte Gametophytes (n) Mitosis and Diploid (n) 5 development Male Sperm (n) gametangium occurs within the sporangia and haploid spores are released to develop into sporophytes Sporangium Stalk Zygote (n) Sporophyte (n) 4 3 Mitosis and development 3 FERNS Seedless vascular plants Like most plants have a dominant sporophyte and a small, inconspicuous gametophyte Diploid (n) Sperm (n) 5 Mitosis and gametangium (n) development Gametophyte (n) Sporangia develop on the underside of leaves of the sporophyte Clusters of sporangia 4 Zygote (n) New sporophyte (n) Formed most of the coal that exists today 3 Mitosis and development Mature sporophyte 4 CONIFEROUS TREES Pine cone holds all of the tree s reproductive stages: spores, eggs, sperm, zygotes, and embryos Sporangia produce Scale spores; spores develop into pollen grains. Sporangium (n) gametophyte is the pollen grain develops into female gametophyte, which makes eggs. Pollen grains (male gametophytes) (n) Spore mother cell (n) Integument 3 Pollination Ovulate cone bears ovules. Male 4 A haploid spore cell Ovule gametophyte carry ovules in the scales of the cone gametophyte (n) Zygote (n) Mature sporophyte Seed coat Seed Embryo (n) Food supply tube to egg and makes and releases sperm. Sperm (n) Male gametophyte (pollen grain) 5 Pollen grows Diploid (n) 6 Zygote develops 7 Seed germinates, into embryo, and ovule becomes seed. and embryo grows into seedling. Fig. 7.7 5
ANGIOSPERMS Flowers contain male and female gametophytes Stamen - include the anther where pollen is released Carpel - female reproductive structure that includes the ovary Stigma Anther Sporophyte (n) 7 Seed germinates, and embryo grows into Seeds plant. Ovule Haploid spores in anthers develop into pollen grains: male gametophytes. Ovary Pollen grains (n) Haploid spore in each ovule develops into female gametophyte, which produces an egg. Ovule 3 Pollination and growth of pollen tube Stigma Pollen grain Pollen tube Sperm Ovules develop into seeds and the ovary matures into fruit 6 Fruit (mature ovary) Diploid (n) 5 Seed Food supply Seed coat Embryo (n) 4 Zygote (n) Fig. 7.9 6 FUNGI Hypha Absorptive heterotrophic eukaryotes Most contain a mass of threadlike hyphae that make up a mycelium Have cell walls made of chitin Cause most plant diseases Spores (n) Heterokaryotic (n + n) (unfused nuclei) Diploid (n) Spore-producing structures Asexual Mycelium reproduction Mycelium Figs. 7.4 & 7.5 Heterokaryotic stage Fusion of cytoplasm Sexual reproduction Fusion of nuclei Spore-producing structures Zygote (n) Germination Germination 7 FUNGI Heterokaryotic (n + n) Diploid (n) Fusion of nuclei Basidia 3 Diploid nuclei Haploid nuclei 4 Spores released Mushroom Growth of heterokaryotic mycelium 5 Germination of spores and growth of mycelia Fusion of two hyphae of different mating types Fig. 7.7 8