Objectives for Lecture 20 green algae Understand the difference between primary and secondary endosymbiosis and be able to state which of the algal groups have chloroplasts that arose by primary or by secondary endosymbiosis Green algae got their plastids from the 1st endosymbiotic event Other algae received plastids from 2nd endosymbiotic event Understand the differences between the three basic life cycle types zygotic meiosis gametic meiosis and sporic meiosis or alternation of generations Zygotic meiosis meiosis occurs in zygote zygote diploid cell resulting from fusion of male female gametes Gamete haploid reproductive cell Gametic meiosis life cycle most familiar to us humans Sporic meiosis alteration of generations gametes haploid zygote diploid Gametophyte haploid gamete producing generation Spore reproductive cell usually unicellular capable of developing into an adult without fusion with another cell Sporophyte diploid spore producing generation Know which life cycle is characteristic of animals and angiosperms Read diagrams above Know the features that green algae share with land plants the evidence that land plants evolved from green algae Cell wall contains cellulose Chl a b carotenoids characteristics of all land plants Be able to name the five evolutionary trends within the green algae Unicellular to multicellular Mobile to immotile flagellum Reproduction asexual to sexual Mainly aquatic but other habitats too NOT SURE OF FIFTH WILL SEND OUT EMAIL WHEN CONFIRMED WITH TEACHER Know the life cycle of the unicellular green alga Clamydomonas Isogamous Asexual reproduction 1 Algae absorbs its flagellum 2 Haploid algal cell then divides mitotically from 2 to 3 times 3 From 4 8 haploid flagellated cells called zoospores develop in this parent cell 4 Zoospores break out of the parent cell and eventually grow to full size Sexual reproduction triggered by starvation for nitrate and phosphate 1 Haploid cells dividing mitotically to produce either or gametes 2 A and gamete come together and shed their cell walls and fuse to form a dipoid 3 This resting stage of a zygote is called a zygospore and withstand bad environmental zygote conditions 4 When conditions are better the thick wall opens and the living zoospore emerges Understand the meaning of the terms isogamy and oogamy and what the benefits of oogamy are Isogamy gametes are similar in size Oogamy egg nonmotile and larger than motile sperm benefits of oogamy Know that Ulva Ulvaphyceae has alternation of generations with independent gametophytes and sporophytes sporic meiosis Life cycle contains gametangium structure in which gametes are formed Sporangium structure in which spores are formed Know the approximate date at which plants colonized the land 450mya Objectives for Lecture 22 Other algae Know what phytoplankton are and what the biological and ecological importance is Plankton are microscopic organisms that drift on the oceans currents They include organisms such as diatoms dinoflagillates krill and copepods as well as the microscopic larva of crustaceans sea urchins and fish Plankton also include tiny photosynthetic organisms that are so numerous and productive that they are responsible for generating more oxygen than all other plants on Earth combined Know what rides tides are what organisms cause them and what their environmental and health effects are Red tides are due to blooms of dinoflagellates some of which produce neurotoxins cause fish kills and paralytic shellfish poisoning in people Be able to name the polysaccharides from red and brown algae that are economically important as emulsifying agents colloidal stabilizers and thickening agents In brown algae alginates Used as thickening agents colloid stabilizers in food textile cosmetic pharmaceutical paper and welding industries In red algea Agar capsules cosmetics culture medium gel electrophoresis Carrageenan stabilizes paints cosmetics and dairy products a clarifying agent in beer For each of the groups of algae Euglenoids Cryptomonads dinoflagellates diatoms brown algae and red algae know what their distinguishing characteristics are in terms of whether they are unicellular or multicellular what their mode of nutrition is and what photosynthetic pigments they have what their cell wall is composed of where they are found fresh vs salt water whether they have flagella and what mode of sexual reproduction they use Euglenoids Phylum Euglenophyta unicellular mobile flagellum no cell wall more like animal Chl a b and carotenoids reproduce by division Cryptomonads unicellular mobile 2 flagellated chl a c and phycobillin provide evidence for secondary endosymbiosis Dinoflagellate red tides caused by this blooms algae that can produce neurotoxins unicellular 2 flagella in different direction most have cell wall cellulose plate zooxanthellae have lost their cell wall and occur as endosymbionts in sponges jellyfish sea anemones corals etc photosyntheic ingest food too chl a c and cartenoids Diatoms single celled most abundant phytoplankton no flagella except during sex chl a c and carotenoids cell wall contains silica Heterokonts flagella differs in size and morphology reproduce mostly asexualy sexual gametic meiosis oogamous multicellular chl a c and cartenoids Heterokonts some alteration of generations kelp laminaria some gametic meiosis rockweed focus Cell wall contains cellulose and alginic acid Brown Algae Red Algae do not have flagella at any stage of their life Chl a phycobilins complex sexual reproduction w alteration of generations cell wall contains agar carageenan cellulose Know what zooxanthellae are Zooxanthellae have lost their wall and occur as endosymbionts in sponges jellyfish sea anemones corals and other marine organisms They are primarily responsible for the photosynthetic productivity that makes possible the growth of coral reefs in nutrient poor tropical waters Know what the term heterokont refers to and which algae are heterokonts Heterokonts have pairs of flagella that differ in size and ornamentation Diatoms and brown algae For the brown algae know the basic body plan is a blade stipe and holdfast and understand why some brown algae have to have sieve tubes Objectives for Lecture 22 Bryophytes Be able to name the three major groups of bryophytes and list the adaptations to dry land found in bryophytes Liverworts Hornworts Mosses Traits in Bryophyte for dry land adaptation common with vascular plants not present in green algae 1 Gametes
View Full Document
Unlocking...