Chapter 17. Plants, Fungi, and the Colonization of Land 2017 Biology2 Chapter 17. Plants, Fungi, and the Colonization of Land

Choleochaete Charophyte(차축조류, green algae의 일종)  plants

17.1 Plants have adaptations for life on land Plants are multicellular photosynthetic eukaryotes that is adapted to the terrestrial life Terrestrial adaptation of plants Root + shoot system Cuticle layer, stoma  prevent dehydration Lignin Vascular system Gametangium (gametangia), pollen grain, ovule: a protective structure where gametes can develop without dehydrating Seed: a protective structure containing a plant embryo and a food supply

Plants evolved from green algae called charophyceans PLANT EVOLUTION AND DIVERSITY Plants evolved from green algae called charophyceans Molecular studies indicate that green algae called charophytes are the closest relatives of plants Coleochaete Chara

17.2 Plant diversity reflects the evolutionary history of the plant kingdom Chaerophyte Bryophyte Lycophyte Pterophyte (Fern) Gymnosperm Angiosperm Apical meristem Gametangium Dependent embyo Vascular system Plant Naked Seed Pollen grain Seed enclosed by fruit Flower Pollen grain

Bryophytes: e.g., moss Two terrestrial adaptations - Waxy cuticle layer -Gametangium: dependent embryo Figure 17.3B

Sperms are flagellated: water is required for reproduction No vascular tissue No lignin-hardened cell wall Spore: a haploid cell that can develop into a haploid multicellular adult without fusing with another cell

Gametophytes (male and female) n Gametes (sperm and eggs) n HAPLOID Meiosis Spores n Mitosis Gametophytes (male and female) n Gametes (sperm and eggs) n Fertilization Zygote 2n DIPLOID Sporophyte 2n

Lycophte, Pterophyte (fern) Bryophyte의 특징 + vascular tissue Sperms are flagellated Seedless vascular plant

Ferns are seedless plants whose flagellated sperm require moisture to reach the egg Figure 17.3C

A major step in plant evolution was the appearance of seed plants Gymnosperms Angiosperms These vascular plants have pollen grains for transporting sperm They also protect their embryos in seeds

Gymnosperms (naked seed plants) Conifers: pine, fir, spruce Nearly all conifers are evergreens Needle-shaped leaves (adaptation to survive dry, cool seasons) The sporophyte (2n) is the dominant generation

소철류 마황

Immature ovulate cone Seed coat Female gametophyte (n) Integument (2n) Spore wall Spore wall Egg nucleus (n) Megaspore (n) Discharged sperm nucleus (n) Megasporangium (2n) Food supply (n) Pollen tube Male gametophyte (n) Embryo (2n) Micropyle Pollen grain (n) (a) Unfertilized ovule (b) Fertilized ovule (c) Gymnosperm seed

17.3 Haploid and diploid generations alternate in plant life cycles ALTERNATION OF GENERATIONS AND PLANT LIFE CYCLES 17.3 Haploid and diploid generations alternate in plant life cycles The haploid gametophyte produces eggs and sperm by mitosis The eggs and sperm unite, and the zygote develops into the diploid sporophyte Meiosis in the sporophyte produces haploid spores, which grow into gametophytes

Gametophytes (male and female) n Gametes (sperm and eggs) n HAPLOID Meiosis Spores n Mitosis Gametophytes (male and female) n Gametes (sperm and eggs) n Fertilization Zygote 2n DIPLOID Sporophyte 2n Figure 17.4

17.6 Seedless plants dominated vast “coal forests” Ferns and other seedless plants once dominated ancient forests Their remains formed coal

17.14 Fungi absorb food after digesting it outside their bodies Plants probably moved onto land along with mycorrhizal fungi (symbiosis) Fungi absorb food after digesting it outside their body  chemoheterotroph, decomposer Fungi belong to the kingdom fungi Secretion of digestive enzymes food absorption

Unicellular fungi: yeast Multicellular fungi: molds and mushrooms Most fungi have the cell wall made of chitin Mold: rapid growing mycelium-forming fungus that reproduces sexually and asexually by producing spores

A fungus usually consists of a mass of threadlike hyphae (singular, hypha) This forms a network called a mycelium (mycelia) Hypha Mycelium

Most fungi cannot move But they grow around and through their food very rapidly

17.15 Fungi produce spores in both asexual and sexual life cycles Yeast: reproduction by budding or cell division Mushrooms and many other fungi Three-phase life cycle Haploid phase Diploid phase Heterokaryotic (dikaryotic) phase

Imperfect fungi (deuteromycetes): fungi that produce offsprings only by asexual reproduction, yeasts and some molds

17.16 Fungi can be classified into five groups 병꼴균류 Fragellated spores 접합균류 내생균근균류 자낭균류 담자균류

Fungal groups include Chytrids (병꼴균류) Fungi with flagellated spores The earliest lineage of fungi

Zygomycetes (접합균류) Zygosporangium Black bread mold

Flagellum Figure 31.13 PLASMOGAMY Mating type () Gametangia with haploid nuclei Mating type () Rhizopus growing on bread 100 m Young zygosporangium (heterokaryotic) SEXUAL REPRODUCTION Dispersal and germination Zygosporangium Flagellum KARYOGAMY Sporangia Diploid nuclei Sporangium ASEXUAL REPRODUCTION MEIOSIS Key Dispersal and germination Haploid (n) Heterokaryotic (n  n) Mycelium 50 m Diploid (2n)

-Glomeromycetes (내생균근균류) Formation of mycorrhiza with plant roots arbuscule

Ascomycetes (sac fungi) (자낭균류) Sac-like structure called ascus that produces spores in sexual reproduction ascus

Basidiomycetes (담자균류) Club-shaped, spore-producing structure, called basidium: mushrooms Figure 17.17E

Terminal cells

Lichens are associations of green algae or cyanobacteria with fungi 17.19 Lichens consist of fungi living in close association with photosynthetic organisms Lichens are associations of green algae or cyanobacteria with fungi food Algae Fungi Minerals and water

Lichens survive in hostile environments Lichens are very sensitive to air-borne pollutants