7Kingdom Protista: Most diverse organisms Animal-like called protozoa Plant-like called algaeDo not have roots, stems, leavesBoth multi-cellular and uni-cellularOne of major producers of nutrients and oxygen
9Classification of Algae classical schemes based on cellular properties
10Algaeeucaryotes that have chlorophyll and other pigments for carrying out oxygenic photosynthesislack well-organized vascular conducting systemhave simple reproductive structuresphycologystudy of algae
11Distribution of Algae primarily aquatic planktonic benthic neustonic suspended in aqueous environmentphytoplanktonalgae and small aquatic plantszooplanktonanimals and nonphotosynthetic protistsbenthicattached and living on the bottom of a body of waterneustoniclive at water-atmosphere interface
12Distribution… some terrestrial on moist surfaces endosymbionts in protozoa, mollusks, worms, and coralsendosymbionts, epiphytes, and parasites of plantsassociate with fungi to form lichens
13Structure of the Algal Thallus (Vegetative Form) thallus (pl., thalli)body of an alga
15Algal Reproduction Asexual fragmentation spores binary fission thallus breaks up and each fragment forms a new thallussporeszoospores – flagellated motileaplanospores – nonmotilebinary fissionmitotic nuclear division followed by cytoplasmic division
16Reproduction… sexual oogonia (s., oogonium) relatively unmodified vegetative cells in which eggs are formedantheridia (s., antheridium)specialized structures in which sperm are formedzygoteproduct of fusion of sperm and egg
17Green Algae Most diverse Major pigmentation is chlorophyll Most live in freshwater, some in oceans, moist soil, tree trunks, in snow, and even in fur of slothsCan reproduce sexually or asexuallyHave a complex life cycle
18Chlorophyta (Green Algae) wide diversity of body formssome have holdfastsreproduce both sexually and asexually
19e.g., genus Chlamydomonas Unicellular forms:e.g., genus Chlamydomonas*fresh water algastigma – aids inphototaxis
20Colonial form Pandorina (simple colony) *16 cells. *Asexual by daughter colonies*Sexual by fusion of motile anisogametes and zygote gives motile zoospores and divided to form daughter colonies.
21Colonial Green Algae Volvox sp. 500-5,000 cells arranged to form a hollow sphereCells are connected by strands of cytoplasm, move togetherA few cells are specialized for reproductionNew colonies develop w/in existing colonies
23CHLOROPHYTA--Volvox ASEXUAL REPRODUCTION: SPHERICAL COLONY OF HUNDREDS OF FLAGELATTED CELLS (colony is motile)ASEXUAL REPRODUCTION:A SURFACE CELL DROPS INSIDE BALL AND BY MITOSIS PRODUCES DAUGHTER COLONY.PARENT COLONY EVENTUALLY BURSTS TO RELEASE DAUGHTER COLONIES.
24CHLOROPHYTA--Volvox Sexual Reproduction: Haploid heterogametes (egg and sperm) from within the parent colony.Sperm and egg fuse to form a diploid zygote.The zygote undergoes meiosis to produce 4 haploid nuclei within the zygote. Only one nucleus survives. It is released as a spore from the zygote and produces a new haploid colony by mitosis.
25CHLOROPHYTA--Volvox Shows some DIVISION OF LABOR within the colony: Vegetative cellsSperm producing cellsEgg producing cellsDaughter colony-producing cells
26Order Volvocales - have flagellated cells and colonies with glycoprotein cell walls Family Volvocaceae - colonial, flagellated cells Volvox sp. - colony of algal cells, usually 500 or more, cells are biflagellated with the colony moving (swimming) as a unit. The spaces between the cell is filled with water and mucilage. The large cells inside are daughter colonies formed by cell divisions (asexual reproduction). Eventually colony ruptures releasing the daughter colonies.
27CHLOROPHYTA--SPIROGYRA Filamentous with spiral chloroplast in each cellForms green “scum” in pondsPyrenoids (sites of starch storage) occur in the chloroplastAsexual reproduction is by fragmentation of the filament.
28CHLOROPHYTA--SPIROGYRA Sexual reproduction by conjugation of isogametes:Two haploid filaments line up.Conjugation tube forms between each adjacent pair of cells.The contents of one cell moves through the conjugation tube and fuses with the contents of the other = diploid zygote.Thick-walled zygospore forms from zygote.The zygospore overwinters.
29CHLOROPHYTA--SPIROGYRA In spring, the zygospore undergoes meiosis to produce 4 haploid nuclei. Only one survives and divides by mitosis to make a new vegetative filament.
30Colonial Green Algae Spirogyra sp. Freshwater Forms long thread like colonies called filaments stacked end to end
32Asexual reproductionis performed by formation of daughter colonies which are produced by specialized reproductive cells called "gonidia" (singular, gonidium).
33Sexual reproduction is oogamous Sexual reproduction is oogamous. The gametes are differentiated into female and male gametes. Female gametes are non-motile and are called eggs and are formed in special reproduction these cells called "oogonia". The male gametes are small and motile each is provided with two flagella and is formed in special reproductive cells called "antheridia". When male gametes are liberated from the antheridium they are attracted with the eggs, and one succeeds in fertilizing the eggs. The zygote forms a thick wall and is transformed to resting zygospores which after a period can germination of the zygote.
34Volvox may represent three evolutionary lines of development: Volvox may represent three evolutionary lines of development: *An increase in the number of cells of the colony. *The specialization of certain cells for reproduction. *Advancement in sexual reproduction from isogamy to oogamy.
35Division: Euglenophyta Division: Euglenophyta *Euglenoids can be found in fresh water in which decaying organic matter is present. *The pigments, chlorophyll and carotenoids give the plant a green colour and are contained in plastids. Unlike the blue- green algae the cell possesses an organized nucleus.
38Division Euglenophyta CHLOROPHYLL a and bcarotenoids, xanthophyllsStore food as PARAMYLON1 TO 3 flagellaNO cell wallPELLICLEsubmembrane protein(glucose polymer)fresh water habitatsHAVE STIGMAphotosensetive eyespot
39Unicellular - Euglenophyta Ex. EuglenaFound in ponds and lakes around the worldPossess chloroplasts–photosynthetic(autotroph)Can also be heterotrophic and absorb decaying organic matterTwo flagellaEyespot-cluster of red pigment-not a real eyeNo cell wall but have a pellicleReproduce by binary fission
40Reproduction Asexual reproduction by longitudinal cell division starting from the front end of the cell
41Sexual reproduction No sexuality is known in Euglena.
42Division: C h r y s o p h y t a Division: C h r y s o p h y t a *The Chrysophyta vary in colour from greenish yellow to golden brown as a result of the predominance of carotenes and xanthophylls. *The food reserves includes "leucosin" a complicated carbohydrate and oils, starch is not formed. In some members the cell wall consists of two overlapping halves and is impregnated with silica. *Members of this division vary in shape. They may be unicellular, motile; or the cells may form colonies, or they may be filamentous multicellular or tubular structure with many nuclei and no cross walls (coenocytes). ***The plants of this division are usually divided into three classes, the yellow green, golden browns and the diatoms.
43"jewels of the sea"Diatoms (Bacillariophyceae) : Diatoms are present in large numbers in almost all types of water: salt, brackish, and fresh.
44An accumulation on the ocean floor of the siliceous cell walls of diatoms has result in enormous deposits of fossils, which now on land are referred to as diatomaceous earth.
45Usage of Diatomaceous earth Usage of Diatomaceous earth * a carrier for liquid nitroglycerin in dynamite. * abrasive in toothpaste. *It is employed extensively in the filtration of liquids. *An excellent insulting material, especially at high temperatures, * in boilers and blast furnaces, small amounts of it in cement greatly increase the strength of concrete.
46Structure of the diatom cell: Structure of the diatom cell: Two major groups of diatoms are known the centrals in which the cell is usually rounded and pinnales in which the cell is elongated. Chemically, the wall composed of pectin and silica. The protoplast of a diatom consists of cytoplasm, a nucleus and one or several plastids bearing a golden-brown pigment that masks the chlorophyll. Food is stored in the form of oil. The cell contains a large central vacuole.
48What are diatoms? Diatoms are single celled algae that have two hard coverings of silica, SiO2, (almost identical to opal). [2,3] The two sides are called the epitheca and hypotheca; they fit together like a box and lid or petri dish, the epitheca overlapping the hypotheca. 
49Reproduction of Diatoms Two individuals come in contact withina mucilaginous envelop. The nucleus ofeach cell divides meiotically to form fourhaploid daughter nuclei out of these fournuclei in each cell, two nuclei thendegenerate. The protoplast of eachcell divides to form two gametes ofunequal sizes each having a nucleus,gamates of one cell fused with the gametesof the other cell to form two zygospores.The two mate zygotes elongate to formauxospores, which develop valves andform new diatoms.
50Phylum Phaeophyta – Brown Algae “dusky plants” Contain chlorophyll a and c & fucoxanthin a brown accessory pigmentDark yellow brown colorLargest & most complex of the algaeFound in cool, shallow coastal waters of temperate or arctic regions
51Phaeophyta – Sagassum sp. Sargassum sp. – form huge floating mats many km long in an area known as the Sargasso Sea near BermudaAlso found on beaches of Caribbean and southern US
52Phaeophyta – “Giant kelp” Giant kelp – grows to 60m
53Phaeophyta – Fucus sp. Fucus has a holdfast to anchor alga to bottom Body is of stipes - flattened stem like structuresBlades are leaf like structuresGas filled bladders keep alga upright in water
54PHAEOPHYTA-Brown Algae multicellular cold water seaweedsFucoxanthin – brown pigmentfood stored as laminarin (future energy source?)source of iodine & algin – used in ice cream
55PHAEOPHYTA-Brown Algae most structurally complex algaeshows tissue differentiationbody is a flat thin thallusexhibit the Diplohaplontic Life Cycle (as do the higher plants)
56PHAEOPHYTA: Fucus Fucus (rockweed) has a flat and dichotomous thallus found in coastal watersholdfasts for anchorageair bladders for buoyancyreceptacles contain conceptacles which produce gametes
57Uses of Algae Major food source for life in the ocean – phytoplankton Produce much of the Earth’s oxygen through photosynthesisNori-dried Poryphora – used to wrap sushiCarrageenan in ice cream, salad dressings, pudding, candy, chocolate milkOther products from algae - pancake syrup, egg nogChemicals from algae are used in plastics, waxes, transistors, deodorants, paints, lubricants, artificial woodAgar derived from algae is used to thicken nutrient mixtures in labs used to grow bacteria