Phylum Phaeophyta, Rhodophyta & Chlorophyta - Multicellular aglae

These are the multicellular algae of the kingdom Protista. Phaeophyta are group of multicellular, eukaryotic organisms that belong to the class phaeophyceae in the division chromophyta.

1. Phylum Phaeophyta [Brown Algae] Presented by: Fasama Hilton Kollie Lecturer, Department of Biology Mother Patern College of Health Sciences March 11, 2019

2. Lesson Outline Overview of the Phylum Phaeophyta, Rhodophyta and Chlorophyta General characteristics of brown, red and green algae Classification of red and green algae Reproduction in multicellular algae; Life cycle of Laminaria Life cycle of Gracelaria Chlamydomonas life cycle Ulva life cycle Ecological and economic importance of brown, red and green algae

3. Lesson Objectives Upon completion of this topic, students will be able to; Identify the basic features of brown, red and green algae Identify how multicellular algae differs in structure and form from other members of the unicellular algae and one from another Describe the structure and function of holdfasts, stipes, blades, bladders, and thalli multicellular algae Draw and discuss the life cycles of luminaria, Gracelia, Chlamydomonas and Ulva ; indicating where meiosis and fertilization occurs

4. Phylum Phaeophyta: Brown Algae Group of multicellular, eukaryotic organisms that b elong to the class phaeophyceae in the division chromophyta Commonly referred to as Brown algae Consist of about 1,500 species Only 6 of the above is found in freshwater 99% are marine organisms

5. General Characteristics: Habitat & Habit 99 % of the brown algae species are found in the marine environment They basically only exist in saltwater forms Few freshwater organisms Solitary, non-motile organism

6. General Characteristics : Size Among the brown algae are the largest of all algae, the Giant kelps May reach a length of over 100 ft (30 m) or more   Lobophora variegata Seen in clear tropical waters in Bahamas Grow's at a depth of 220 meters (730 feet)

7. Examples of Giant Kelps Macrocystis pyrifera Nereocystics luetkeana Laminaria saccharina  (kelp )

8. Consist of tiny species such as Ralfsia expansa , commonly know as tar spot Size Cont’d… Ralfsia expansa Ralfsia forgiformis Ralfsia verrucossa

9. General Characteristics: Morphology Brown algae have a plantlike body called Thallus The complete body of a seaweed Thalli are typical of algae, fungi, lichens, and some liverworts. Sea lettuce (Ulva )

10. Kelp thallus has three main parts Holdfast Stipe Blades Contain gas-filled floats (Bladder) Pneumatocyst Morphology Cont’d… Thallus

11. Thallus Morphology Representation

12. Thallus Morphology Representation

13. Algin or alginic acid occurs on or in the cell walls of brown algae It constitute about 40% of the dry weight of some kelps General Characteristics Cont’d…

14. General Characteristics: Locomotion Has no locomotory organ or structure Movement is possible due to water current

15. General Characteristics: Mode of Nutrition Brown algae are generally photosynthetic Consist of chlorophylls a and c Plastid has large amount of fucoxanthin which gives them a characteristic brown or olive color Their main food reserve is Laminarin

16. Reproduction In Brown Algae Undergo both asexual and sexual reproduction Several other brown algae reproduce asexually by fragmentation Eg ; sargassum Sargassum muticum

17. Sargassum Examples

18. Sexual reproduction is common and associated with gametes They have a life cycle in which there is an alternation of heteromorphic generations Brown algae have large and conspicuous sporophyte Gametophyte is microscopic Reproduction In Brown Algae Cont’d..

19. Laminaria Life Cycle

20. Red Algae [Phylum Rhodophyta]

21. Phylum Rhodophyta: Red Algae A large Phylum of the Kingdom Protista, consisting of mostly multicellular aquatic organisms Commonly referred to as Rhodophytes or Red algae Appx 5,000 species Eg : Polysiphoni , Porphyra , Batrachospermum , Corallin

22. General Characteristics Cont’d… Red algae may have been the first eukaryotes formed by endosymbiosis involving photosynthetic prokaryotes Found in both marine and freshwater environment Approximately 5% of the red algae occur in freshwater environments with greater concentrations found in the warmer area Consist of thallu -like body measuring up to about 10 centimeters (3.9 inches) in length

23. General Characteristics Cont’d… Different species may be free living, epiphytic, or parasitic Contain chlorophyll a and d Phycoerythrin, Phycocyanin, and allophyocyanin as accessory pigments cell walls of red algae have cellulose as a framework and mostly mucilages in nature containing agars and carageenans

24. General Characteristics Cont’d… Some do contain calcium carbonate in their cell wall. Such organisms are commonly referred to as Coralline algae Not all red algae are red, Some are blue-green or olive Absence of flagella and centriole Coralline algae

25. Classification of Red Algae There are two classes of red algae namely: Florideophyceae Bangiophyceae Both Florideophyceae and Bangiophyceae  comprise 99% of red algae diversity in marine and freshwater habitats.

26. Filamentous  structure Pseudoparenchymatous Apical growth, Complex oogamy ( triphasic ) Eg : Gracilaria , Ceramiales etc Classification of Red Algae Florideophyceae (98 %): Gracilaria spp.

27. Gracilaria hayi Collaline algae Agardhiella Ceramiales

28. Unicellular, filament, blade structure Have diffuse growth pattern E.g. Porphyra Classification of Red Algae Bangiophycidae (1%): Porphyra

29. Reproduction In Red Algae Red algae are know for the complexity of their life cycles Most have three(3) multicellular phases; A haploid gametophyte Two diploid sporophytes One of the sporophytes phases, Tetrasporophyte , produces spores called tetraspores by meiosis Tetraspores germinate and grow into male or female gametophyte

30. Reproduction In Red Algae Male gametophytes release nonflagellated gametes, called spermatia Spermatia is transported to female gametophyte via water current Following fertilization, the zygote divides repeatedly by mitosis, producing the second sporophyte phase, Carposporophyte This remain attached to the female gametophyte

31. Gracelaria Life Cycle

32. Reproduction In Red Algae Carposporophyte releases spores called carpospores This develop into new tetrasporophytes

33. Economic Importance Red algae are ecologically significant as primary producers, providers of structural habitat for other marine organisms, and their important role in the primary establishment and maintenance of coral reefs. Some red algae are economically important as providers of food and gels. For this reason, extensive farming and natural harvest of red algae occurs in numerous areas of the world

34. Green Algae [Phylum Chlorophyta ]

35. Phylum Chlorophyta: Green Algae Green algae F rom two Greek roots chloros - “ Green ” and phyta – “ Plant ” The reference is to the typical color of member of the phylum 7,500 extant species

36. General Characteristics: Habitat & Habit Most live in fresh water Some serve as seaweeds or parts of phytoplankton in oceans Others are terrestrial, growing in moist places favored by mosses and ferns Some establish symbiotic relationships with other organisms Eg : Lichens

37. General Characteristics: Size Some are unicellular and microscopic The green alga Micromonas is only 1 µm in diameter—the smallest eukaryotic cell known Micromonas pusilla

38. General Characteristics : Morphology Green algae species shows different body type Some may be unicellular Some colonial Filamentous as in Ulothrix and Spirogyra Some plant-like marine forms as in Fristschiella and Ulva Chlamydomonas

39. Morphology Cont ’d… The cells possess one to many chloroplast Green algae have Chlorophyll a and b , carotenes and xanthophylls They store starch inside plastids as a food reserve

40. General Characteristics Cont’d… Green algae share numerous characteristics with plants Have chlorophylls a and b Use sugar and starch as food reserves Many have cell walls of cellulose

41. Classification of Green Algae There are several classes of green algae that comprise of about 7,500 extant specie Class Chlorophyceae Class Ulvophyceae Class Charophyceae

42. Class Chlorophyceae: Chlamydomonas Most unicellular or colonial organisms Eg ; Chlamydomonas A unicellular freshwater alga commonly found in ponds Each cell has two flagella with single chloroplast Reproduce both asexually and sexually

43. Morphology of Chlamydomonas reinhardii

44. Class Chlorophyceae Both methods begin when a mature, haploid cell divides two or more times by mitosis, producing up to 16 daughter cells These cells develop flagella before breaking out of parent cell’s wall In asexual reproduction, the daughter cells are zoospores They develop directly into mature haploid cells

45. Class Chlorophyceae Con t’d… In sexual reproduction, daughter cells are gametes Gametes are Isogametes and are designated either + or – mating type Zygote form by fusion of + and – mating type which secretes a thick wall The wall zygote is know as a zygospore The zygote produces four flagellated haploid cells inside the wall by meiosis

46. Chlamydomonas Life Cycle Zygospore

47. Chlorophycean: Chlorella Chlorella is another unicellular chlorophycean It’s studied as one of the possible food source for humans Almost entirely digestible It weights almost 50% protein It grows rapidly in sewage or waste medium

48. Chlorophycean: Volvox Volvox is the best-known colonial chlorophycean It consist of few hundred to thousand photosynthetic cells arranged in a single layer at the surface of a hollow sphere Consist of a light detector This controls the beating of their flagella and directs the colony toward light

49. Class Ulvophyceae Ulva is a marine ulvophycean Found attached to rocks in tide pools and exposed areas Sea lettuce (Ulva)

50. Class Ulvophyceae Cont’d… Reproduce asexually and sexually Life cycle involves an alternation of isomorphic generations Both are bright green, flat thalli resembling a thin rubbery leaf of lettuce Gametophytes are designated + or – mating string

51. Life Cycle of Ulva

52. Class Ulvophyceae Cont’d… Example of other ulvophyceans Acetabularia Cephaleuros Cladophora , Codium Acetabularia is usually found in warm tropical water where it exist as a single cell for most of its life Cephaleuros lives on the leaves of tea plants and is responsible for red rust

53. Other Forms of Ulvophyceans Cladophora Cladophora Codium

54. Class Charophyceae Charophyceans include unicellular, colonial, and multicellular green algae The Coleochaetles and Charales are the two orders of charophyceans with the closest relatives of plants Coleochetales consist of filamentious algae that live in shallow regions of freshwater Eg : Coleochaete

55. Class Charophyceae Charales charophyceans form mineralized cell walls Contains CaCO 3 and MgCO 3 Stoneworts Eg : Chara

56. Reference Nabors , Murray W., Introduction To Botany. Copyright 2004 Pearson Education, Inc., publishing as Benjamin Cummings, 1301 Sansome St., San Francisco, CA 94111. www.aw-bc.com https:// en.m.wikipedia.org/wiki/Alginic_acid Davies, JC (2002). "Pseudomonas aeruginosa in cystic fibrosis: pathogenesis and persistence". Paediatric Respiratory Reviews.

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