Presentation on theme: "Brown Algae or Phaeophyta Marine and multicellular"— Presentation transcript:
1 Brown Algae or Phaeophyta Marine and multicellular Sample of Protistan DiversityBrown Algae or PhaeophytaMarine and multicellularBrown or olive in colorStructural and biochemical adaptations of seaweedsLive in tidal and intertidal regions so they need some strength, structure and desiccation protection to handle such environments.Structural AdaptationsThallus: body but lacks roots, stems and leavesHoldfastStipe: stem likeBlades: for PS
2 Biochemical Adaptations Sample of Protistan Diversity.Biochemical AdaptationsCell walls have cellulose and polysaccharides that give them a slimy feel and this protects them against hard surfaces during wave action.Ecological ImportFood sourceLaminaria is in soupRed alga, Porphyra is the wrap in sushiRich in iodineAlgin in the algae is used to make agar, thickeners for pudding and salad dressing and of course oil drilling lubricants (but you probably already knew that.)
4 Figure 28.20x1 Kelp forestMacrocystis is one kind in Monterey
5 Some algae have life cycles that alternate generations Introduction Sample of Protistan DiversitySome algae have life cycles that alternate generationsIntroductionWhat does it mean to “Alternate Generations?”During the life time of the organisms there exists multicellular stage when it is haploid and a multicellular stage when it is diploid. You see, humans have a haploid and a diploid stage but the haploid stage is not multicellular.Laminaria as an example (Fig )Laminaria can easily be seen along the coast and what you are looking at is the sporophyte generation or 2N.The sporophyte produces spores which are 1N in sacs called sporangia. This is done by meiosis
6 These gametophytes are much smaller than the sporophyte. Sample of Protistan DiversityThese spores can germinate into a male gametophyte or a female gametophyte.These gametophytes are much smaller than the sporophyte.The male gametophyte releases sperm while the female gametophyte produces eggs which remain on or attached to the gametophyte. The sperm must obviously swim to the eggs. This is thought to be aided by the use of a released chemical attractant.Sperm fertilize egg. This is called syngamy. We are now back to a 2N zygote.The zygote develops into the mature sporophyte on the female gametophyte where it was fertilized.Since the gameto- and sporophyte look different they are called heteromorphic.
7 Figure 28.21 The life cycle of Laminaria: an example of alternation of generations
8 Rhodophyta or Red Algae Red due to the pigment phycoerythrin. Sample of Protistan DiversityRhodophyta or Red AlgaeRed due to the pigment phycoerythrin.These algae can look rather purplish.They can be seen in Monterey as well as warmer waters.They absorb blue and green wavelengths that travel farther into the water so these algae can exist deeper.
9 Figure 28.22 Red algae: Dulse (top), Bonnemaisonia hamifera (bottom)
10 Chlorophyta or Green Algae Sample of Protistan DiversityChlorophyta or Green AlgaeThe chloroplasts of green algae and those of plants are so similar that they are though to share a common ancestor.Fresh and Marine watersLichens: a symbiotic (mutualistic) relationship between a fungi and a green alga.Example: Chlamydomonas, Volvox, Ulva, SpirogyraUnicellular or colonies or multicellular species
13 The use of pseudopodia for movement and feeding Introduction Sample of Protistan DiversityThe use of pseudopodia for movement and feedingIntroductionSo these protists can be heterotrophs since they use pseudopodia.AmoebasUnicellular and use pseudopodiaTip of the pseudopod gets anchored and then the cytoplasm streams towards this tip.Cytoskeleton of microtubules breaks down and reforms.Fresh and marine environments, soilCauses amoebic dysentery (Montezuma’s revenge)
14 Actinopoda (Radiolarians) Sample of Protistan DiversityActinopoda (Radiolarians)Really slender pseudopodia called axopodia that gives these protists a “radiance.”Reinforced with microtubulesthe axopodia extend out, increase surface area and help with floatation.the axopodia can be used as a food capturing tool as microorganisms can stick to the axopodia and are then phagocytized.
16 Figure 28.27x Radiolarian skeleton Skeletons of silica
17 Porous shells (foramen = little hole) shells of calcium carbonate Sample of Protistan DiversityForaminiferaPorous shells (foramen = little hole)shells of calcium carbonatecytoplasmic strands extend through the pores, increasing surface area.Some have a symbiotic relationship with an alga which live in the calcium carbonate shell.
18 Mycetozoa or Slime Molds Introduction Sample of Protistan DiversityMycetozoa or Slime MoldsIntroductionthey decompose dead organic matter.move by pseudopodia and feed by pseudopodiathere are two main kinds of slime molds (just our luck)plasmodialcellular
19 Plasmodial Slime Molds bright in color – yellow or orange Sample of Protistan DiversityPlasmodial Slime Moldsbright in color – yellow or orangethe feeding stage is called a plasmodium which is an amoeboid mass.it is not multicellular; just a mass of cytoplasmengulfs food by phagocytosisExample: Physarum
20 Figure 28.29 The life cycle of a plasmodial slime mold, such as Physarum
22 Figure 28.1c Too diverse for one kingdom: a slime mold (Physarum polychalum)
23 Example: Dictyostelium Sample of Protistan DiversityCellular Slime Moldsfeed as individual cells when food is present but will aggregate when food is depleted.cellular mass looks like a Plasmodial slime mold but there are cellular membranes.Haploid organismsExample: Dictyostelium
24 Figure 28.30 The life cycle of a cellular slime mold (Dictyostelium)
25 This is another “biggee.” Sample of Protistan DiversityMulticellularityThis is another “biggee.”A lot of these protists were unicellular but the unicellular eukaryotes gave way to multicellular adaptations that brought about a new explosion in diversity Fungi, plants and animals.