Biology11Day4– ClassificationofAlgae

LearningObjectives:

• Becomefamiliarwithbiologicalnomenclature• DistinguishbetweenRhodophyta,Phaeophyta,andChlorophyta• IdentifyfeaturesofeachbodytypewithinChlorophyta• NameanddescribegroupswitheachbodytypewithinChlorophyta• ExplainthebiologicalsignificanceofVolvox andUlva

• Textbookp.435-439,StudyGuidep.40-42

Nomenclature

• SpeciesaredescribedwithatwopartnamingsystemdevelopedbySwedishbotanistCarlLinnaeus.• RecallthatorganismsarepartofaKingdom,Phylum,Class,Order,Family,Genus,andSpecies.Allofthesehavelatinnamesrecognizeduniversallywithinwesternscience.• Latinnamesarealwayswritteninitalics.• SpeciesaredescribedwithGenusspecies.• Forexample,theDouglasfiriscalledPseudotsuga menziesii.HumansareHomosapiens.• WearepartofthegenusHomo,speciessapiens.

AlgaeClassification• Therearethreemaingroupsofalgae: Rhodophyta,Phaeophyta,andChlorophyta

• Rhodophyta isknownasredalgae• Phaeophyta isknownasbrownalgae• Chlorophyta isknownasgreenalgae

Algae

Rhodophyta Phaeophyta Chlorophyta

Rhodophyta – TheRedAlgae

• Marinealgaepresentallovertheworld• Containspigmentschlorophyll-a,chlorophyll-d,andphycobilin.• Canlivequitedeepunderwaterduetoaccessorypigmentphycobilin whichisefficientatabsorbingbluelight.• Nori,theseaweedusedtowrapsushirolls,isdriedPorphyra,atypeofredalgae.

Phaeophyta – TheBrownAlgae

• Mostseaweedisbrownalgae• Livesintemperateorarcticwaters• Includesthelargestalgae–GiantKelp

Chlorophyta –TheGreenAlgae

• 4typestypes:unicellular,colonial,filamentous,leaf-like.• Primarilyinmoistareasonlandandinfreshwater.• Reproductivecycleincludessexualandnon-sexualstages.• Similartolandplants:Havecelluloseintheircellwalls,containchlorophyllsa andb,storefoodintheformofstarch,andhasareproductivecycleremarkablesimilartomoss.• Scientistsbelievethatgreenalgaeandmosssharedacommonancestor

Algae

Rhodophyta Phaeophyta Chlorophyta

Algae

Rhodophyta Phaeophyta Chlorophyta

Unicellular Colonial Filamentous Leaf-Like

Unicellular- Chlamydomonas

• Growsinponds,ditches,andwetsoil.• Mainfeatures:2flagellaforamovementandaneyespottodetectlight,cup-shapedchloroplastforphotosynthesis,pyrenoid tosynthesisandstorestarch.• Nocelluloseincellwall

Colonial- Volvox

• Colonialorganismsliveincommunitieswheremanysmallindividualsworktogethertobehaveasonelargerindividual.

• Volvox comesincommunitiesof500– 50000cellsthatworktogether.

• Cellsareconnectedtoeachotherbystrandsofcytoplasm,allowingthemtocommunicate.

• Afewcellsarespecializedforreproduction.• Volvox straddlescolonialandmulticellularlife.

Filamentous– SpirogyraandOedogonium

• Formlongthread-likecolonies.• Canreproduceasexually.Ifthestrandisbroken,bothpieceswillcontinuetodivideandgrow.• Theycanalsoreproducesexuallyusingspecializedreproductivecellscalledgametes.

Leaf-life- Ulva

• Multicellulargreenalgaealsocalled“sealettuce”.• Commonlyfoundalongrockyseacoasts.• Toughenoughtowithstandwaves,heldinplacebyaholdfast.• Ulva issignificantinbiologybecauseit’sreproductivecycleisverysimilartothatofmossesandferns.

AlternationofGenerations

• Manynon-vascularplants(Ulva,someotheralgae,mosses,andferns)useareproductivestrategycalledalternationofofgenerations.• Theywillreproducesexually,thenasexually,thensexually,thenasexually,etc.• Onegenerationwillbehaploid,thenextwillbediploid,thenextwillbehaploid,etc.

Checkyourunderstanding• Howisredalgaeadaptedtolifedeepunderwater?• Itcontainsphycobilin,apigmentefficientatabsorbingthebluelightthatmakesitdeepbelowthesurface.• WhichphylumdoesmostofourseaweedhereinCanadabelongto?• Phaeophyta – Brownalgae• Whatisthepurposeofapyrenoid?• Synthesizesandstoresstarch.• WhatisthebiologicalsignificanceofVolvox?• Bridgesthegapbetweencolonialandmulticellularlife.• WhatisthebiologicalsignificanceofUlva?• Exhibitsalternationofgenerations,similartomossesandferns.