BIOL 112 1ST Edition Exam 3 Study Guide Lectures 23 33 Lecture 23 October 24 Seed Plant History Land plants vascular plants progymnosperms seed plants seedless vascular plants dominate gymnosperms gymnosperm forests dominate cycads and conifers dominate angiosperms Reproductive Adaptations of Seed Plants Heterospory and Reduced Gametophytes seed plants are heterosporous spores remain within sporophyte tissue and grow into male or female gametophytes megaspores female gametophytes microspores male gametophytes ovule on a sporophyll egg is produced and fertilized in the megasporangium pollen pollen microspores tiny male gametophyte in sporopollenin travel in the air to the ovules pollination pollen grows a pollen tube toward the egg in within the ovule then the sperm is released fertilization occurs within the ovule conifers and angiosperms have no flagella seed from the fertilized ovule seed coat food embryo efficient dispersal enhances survival on land underground germination growth without photosynthesis Gymnosperms naked seed plants Ovules exposed on sporophylls usually in cones Ginkgophyta Medicine flagellated sperm Cycadophyta Central male or female cone flagellated sperm ex sago palm Gnetophyta Non motile sperm Coniferophyta Most diverse Make pollen cones Female ovulate cones Evergreen with needle leaves Know the pine life cycle Lecture 24 October 27 Angiosperms Derived Characteristics Flower protects ovules with in the ovary Promotes efficient pollen transfer by pollinators 4 whorls of modifies leaves Know the parts and their functions Flowers can be missing parts incomplete Unisex flowers only male or female carpels or stamens No petals wind pollinated Inflorescence groups of flowers more attractive to pollinators ex bluebonnet sunflower Floral scent and color attracts pollinators Nectar and pollen keeps pollinators coming Coevolution of plants and pollinators same species of pollinators go to the same species of flower Some flowers do not reward pollinators ex orchid with wasp pheromones Fruit enhances seed dispersal Protects dormant seed Derived from ovary tissue after fertilization Fleshy fruit from ovary wall contains seeds eaten by animals Dry fruit dispersed by wind water or animals also protects the dormant seed Lecture 25 October 29 Angiosperm life cycle Pollen grains from anthers Ovules enclosed within ovary Pollen lands on stigma Double fertilization with 2 sperm nuclei One fertilizes the egg zygote Other fuses with 2 central nuclei forming a 3n food supply endosperm Anthophyta includes extant angiosperms 3 basal clades amborella water lilies star anise Magnoliids are separate Monocots Large endosperm and 1 cotyledon ex grasses grains palm trees some garden plants Eudicots Endosperm absorbed into 2 cotyledons ex most fruits veggies trees and shrubs Fungi Multicellular and terrestrial Except for aquatic chytrids and unicellular yeasts Mycelium main fungus body for feeding and growing Usually underground or within a host Network of filamentous hyphae Hyphae Secretes hydrolytic enzymes and acids to digest simple organic materials Simple organic molecules absorbed absorptive heterotrophs Made of tubular cells with rigid cell walls of chitin Multicellular hyphae allows cytoplasmic streaming Septae septum with pores Coenocytic multi nuclei no cross walls Rapid growth toward new food with huge surface area for absorption Some specialized hyphae Haustoria penetrate cell walls of plants but not the plasma membrane Some hyphae catch nematodes Lecture 26 October 31 Fungus reproduction not chytrids Haploid spores made in sexual and a sexual cycles Germinate on food source Each spore grows into a haploid mycelium Sexual cycles do not make male and female gametes Only mating types 3 steps to form a zygote 1 Plasmogamy fusion of haploid hyphae 2 Heterokaryotic stage hyphae with unfused haploid nuclei of both types 3 Karyogamy fusion of haploid nuclei to form a zygote The zygote undergoes meiosis making genetically diverse spores There is never a multicellular diploid stage Asexual reproduction is common Genetically identical spores made by mitosis that grow into mycelium mold Fragmentation of mycelium can grow into new individuals Yeasts can bud off into daughter cells by mitosis Phylogeny Opisthokonts Unicellular flagellated ancestor Some lichen fossils are very old Early plant roots had mycorrhizae Phylogeny Only chytrids have flagellum and are aquatic Importance of fungi Decomposers Fungus can break down wood lignin Dry rot wet rot mold mildew Mutualists Mycorrhizae close association with most plant roots Helps plant absorb water and minerals Increases surface area Fungus gets sugars from plant Lichens close association with photosynthetic unicellular chlorophyte or cyanobacteria Fungus gives framework water and minerals Algae cyanobacteria gives sugar from photosynthesis Soredia reproduce as dual organism Pioneers on bare rocks and soils for plants Pathogens Infect plants ex rust smut ergot molds Infect animals ex chytrid Infect humans mycosis infection due to fungus Medicine and research Antibiotics and other meds Genetic research Food Fermentation beer bread Food processing bleu cheese soy sauce Poisonous fungi Lecture 27 November 3 Animal diversity Structure Multicellular ingestive heterotrophs No cell walls Cells joined by extracellular proteins esp collagen Specialized nerve and muscle cells Unique to animals Organized into tissues Life cycle Mostly sexual reproduction Most have separate sexes Hermaphrodites have male and female structures in one organism Asexual in some Budding fragmentation parthenogenesis Always diploid except eggs and sperm Embryonic development Similar genes that control development Zygote cleavage blastula Gastrulation Forms gastrula with blastopore archenteron Creates germ layers endoderm and ecdoderm Most have a larval stage before adult stage Differs in form function and habitat from adult Undergoes metamorphosis to adult form Animal history Unikonts and opisthokonts Choanoflagellates are the closest protest group to animals Collar cells found in some animals Genetically similar Proterozoic pre cambrian animals Ediacaran biota 565 mya earliest jellyfish like fossils Paleozoic era animals Cambrian explosion 535 mya Dramatic diversification Almost all major phyla present Mineralized skeletons and shells Lecture 28 November 5 Animal body plans Most animals are symmetric Radial symmetry usually sessile or planktonic Bilateral symmetry usually