The document describes characteristics of three major divisions of algae - Chlorophyta, Rhodophyta, and Phaeophyta. It provides details on their nuclei, color, flagellation, morphology, reproduction, life cycles, chloroplasts, and other distinguishing features. Examples are given of representative algae from each division, including images showing their structures and life cycles. Key aspects like heteromorphic or isomorphic alternation of generations, and gametic, sporic or zygotic life histories are highlighted.

1. CHLOROPHYTA

2. CharacteristicsNUCLEUSUninucleate

3. Multinucleate

4. Cells are eukaryoticCOLOURGreen

5. Some may be red or orangeFLAGELLATIONVegetative and reproductive cells are motile

6. 2 or multiples of 2 flagella equal in length

7. No mastigonemesMORPHOLOGYUnicellular flagellates

8. Colonial flagellates

9. Non-motile unicells

10. Non-motile colonies

11. Branched or unbranched filaments

12. Parenchymatous or siphonousthalliREPRODUCTIONvegetative: cell division, autocolony formation, fragmentation

13. asexual: zoospores or autospores

14. Sexual: isogamous, anisogamous or oogamous

15. Resting stages: eukaryotic akinetes, may form thick walls and become resting sporesLIFE HISTORYZygotic

16. Sporic

17. GameticCHLOROPLAST2 membrane envelopes

18. No PER

19. Thylakoids in stacks of several to many

20. DNA scattered

21. Starch is stored within the chloroplast

22. Conspicuous chloroplastsEYESPOT- Within the chloroplast but not associated with the flagella

23. Acrosiphonia sp. Ploidy: NLife History: Sporicheteromorphic

24. Codium fragileCoenocytic

25. Dichotomously branched

26. multinucleatePloidy: 2nLife History: Gametic

27. Codium Sporangia

28. Codium Utricle

29. Prasiola sp.

30. UlvalinzaParenchymatous bladeUlvaintestinalis Tubular blade formation

31. UlvalactucaParenchymatous blade formation

32. Example of a Chlorophyte

33. Example of a Chlorophyte 2

34. Example of a Chlorophyte 3

35. Example of a Chlorophyte 4: Volvox sexual reproduction

36. Example of a Chlorophyte 5

37. Example of a Chlorophyte 6

38. Example of a Chlorophyte 7oogoniaAntheridium

39. Chloroplast of a desmidNote the pronounced stacking of the thylakoids

40. The 2 membranes of the chloroplast envelope and the scattered light areas containing fibrils of DNA

41. green algal chloroplasts are similar in many respects to those of high plantsChlamydomonasUpper: diagrammaticLower: electron micrograph

42. Section through the eyespot of ChlamydomonasThese eyespots may be one or several layers thick

43. they are located within the chloroplast but not close to the flagella

44. the eyespot operates by intercepting (shading) and/or reflecting (increasing the illumination) light onto the photoreceptor pigment, which is localized in either the plasma or chloroplast membranes over the eyespot

45. note the stacking of the thylakoidsPortions of sections through chloroplasts of the ChlorophytaThis is the only algal phylum in which starch is stored in the chloroplast

46. It may be in a sheath surrounding the pyrenoid and/or in other parts of the chloroplastChloroplast of a ‘higher plant’Compare to previous slide

47. note the arrangements of the thylakoids into grana stacks (dark areas) which are connected by stroma lamellae

48. the scattered areas containing chloroplast DNA (in between the grana stacks) (NA)

49. RUBISCO in higher plants is found in the stroma of the chloroplast (S)RHODOPHYTA

50. CharacteristicsNUCLEUSVery small nuclei

51. Often multinucleateCOLOURPink, Red, Purple, Black, Bluegreen, BrownishFLAGELLATIONNoneMORPHOLOGYSimple microscopic unicells- Branched filaments- Corticated filamentsCorticating cells surround in clusters the main filament- pseudofilaments- PolysiphonousfilamentsPolysiphonous cells arrange themselves like flower petals around the main axial cell by pitplugs- Parenchymatousthalli- Large complex pseudoparenchymatousthalliUniaxialpseudoparenchyma: 1 main filament with many coming off the sidesMultiaxialpseudoparenchyma: many main filaments together with many coming off the sidesREPRODUCTION- Cell division:Unicells undergo simple cell divisionFilaments undergo cell division and elongation which can be apical and/or intercalarly- Sexual Reproduction:Oogamous by fusion of spermatia (non motile male sex cell) with a carpogonium (female reproductive organ)CHLOROPLASTS- Chlorophyll a- Unstackedthylakoids- 2 membranes around the chloroplast- Starch is the storage product- Stellateor discoid chloroplast shapes- Phycobilisomespresent- Pyrenoids(centers of carbon dioxide fixation within the chloroplasts) store RUBISCOChloroplast DNA Is scattered in nucleoidsEYESPOTSNoneCharacteristics Part 2LIFE HISTORYSporic meiosis with an alternation of isomorphic or heteromorphic generationsRed algae:Male gametophytes (n) produce spermatia (non motile male sex cells)Female gametophytes produce carpogonia (egg cells) that are retained on the female gametophyte plantAfter fertilization the zygote (2n) stays on the female gametophyte and develops into a carposporophyte (2n)This carposporophyte produces carpospores (2n) that are released and become tetrasporophytesEach tetrasporophyte produces tetrasporangia where meiotic divisions result in tetraspores (n) Polysiphonia: IsomorphicTetrasporophyte (2n)(small plant) is forming tetrasporangia (round balls)These tetrasporangia divide into four parts  four spores (n) are then formedFrom these spores, male and female gametophytes formTetrasporophytes and gametophytes look identicalThe spermatangia (male reproductive organs) are formed at the top of the branches of the gametophyte (look like small cucumbers) are crowded with spermatia (non motile male sex cells)Spermatia can melt together with the carpogonium (female reproductive organ also know as the oogonium)Nucleus of the male cell moves through the tube of the trichogyne (hair like receptive protuberance of the carpogonium) to the egg cell and a zygote is formed that develops into a cystocarp (fruiting structure with a special protective envelope produced after fertilization)In the cystocarp, carpospores are formed (2n) which escape through a hole and the top and can grow into a tetrosporophyte Porphyra: HeteromorphicConspicuous blades are gametophytes (n) that bear either spermatia or carpogonia or bothFertilization occurs in the situ on the female gametophyteThe zygote remains in the female gametophyte blade and divides to form many carpospores (2n)The carpospores are released and germinate to produce the “Conchocelis” stage (2n)This stage burrows into shells (i.e. oysters and clams) and produces spores called conchosporesConchospores form new thallus Mastocarpus: HeteromorphicFemale gametophyte (n) produce carpogonium (trichogyne + egg)Male gametophyte produce spermatia (n)Spermatia and carpogonia fuse to form carposporophyte (2n)Carposporophyte forms carpospores (2n)Carpospores are released and form tetrasporophyte (2n) Tetrasporophyte form tetrasporangia and meitotically divide to form tetraspores (n) which then go back to forming the male and female gametophytes

52. Mastocarpuspapillatus/PetrocelisMastocarpus – N (gametophyte)Life History: sporicheteromorphic life historyPetrocelis – 2N (tetrasporophyte)- Dark purple to nearly black

53. Mastocarpus Life Cycle

54. Mastocarpus

55. Petrocelis phase

56. Chondracanthusexasperatus

57. MazzaellasplendensIf there are cystocarps (N) present containing carpospores (2N) then it is a gametophyte (N)

58. if these are not present then its a tetrasporophyte (2N)- Life history: Sporicheteromorphic

59. SparlingiapertusaPloidy: if there are bumps then it’s a gametophyte (N) with cystocarps; if not, then it’s a tetrosporophyte (2N)Life History: Sporicheteromorphic

60. Polysiphoniapacifica

61. HildenbrandiaThinnest of the crusts

62. bright orange/red in colourGracilariapacificaPloidy: if there are bumps then it’s a gametophyte (N) with cystocarps; if not, then it’s a tetrosporophyte (2N)Life History: Sporicheteromorphic

63. PolyneuralatissimaPloidy: if there are bumps then it’s a gametophyte (N) with cystocarps; if not, then it’s a tetrosporophyte (2N)Life History: Sporicheteromorphic

64. Grateloupiadoryphora

65. PorphyrafallaxPloidy: NLife History: SporicHeteromorphic- Conchocelis stage is 2N

66. Example of a Rhodophyte: Polysiphonia

67. Example of a Rhodophyte 2: Porphyra

68. Example of a Rhodophyte 3: Hollenbergia

69. Conchocelis phase of Porphyra

70. PHAEOPHYTA

71. CHARACTERISTICSNUCLEUS Uninucleate

72. EukaryoticCOLOURBrownFLAGELLATIONTwo heterokont flagella (only reproductive cells)

73. Long flagellum has 2 rows of mastigonemes

74. Shorter flagellum is smooth and directed backward

75. Has a light receptor

76. Attached laterallyMORPHOLOGYMulticellular

77. Sometimes very large

78. Unbranched filaments

79. Parenchymatous

80. Pseudoparenchymatous is rare

81. Have a meristoderm:

82. small surface cells with chloroplasts and capable of division

83. cortex:

84. general larger cells lacking chloroplasts which do not divide

85. Medulla:

86. trumpet hypae cells formREPRODUCTIONvegetative: formation of propagules or by fragmentation,

87. Asexual: by zoospores formed in plurilocular sporangia

88. Sexual: fusion of isogamous, oogamous LIFE HISTORYGametic:

89. gametes range from oogamous to isogamous

90. SporicEYESPOTIn spores or gametes within the chloroplast and associated with a flagellum

91. Present and acts as shading or light reflectorCharacteristics Cont’dCHLOROPLASTOne to many smooth chloroplasts

92. Storage product is stored outside the chloroplast

93. 4 membranes surround the chloroplast

94. 2 membrane envelope and PER

95. Thylakoids are in stacks of 3

96. Girdle lamella is presentOTHERDNA is ring shaped

97. RUBISCO in the pyrenoids

98. Cell wall always present – made of cellulose, alginic acid and polysaccharides

99. Sieve elements: perforated cross walls in large kelps for conduction of photosynthateFucales: SargassummuticumPloidy: 2NLife History: Gametic meiosis forms gametes which fuse to form a diploid zygote that grows into the adult plantOther: has short stubby receptacles that bear oogonial and antheridial conceptacles

100. Fucales: FucusgardneriPloidy: 2NLife History: gametic meiosis forms gametes which fuse to form a 2N zygote that grows into the adult plantOther: parenchymatousthalli with apical meristemsAnatomy: meristoderm, cortex and medulla present- Receptacles (ends of blades) contain pores (small depressions) under which are conceptacles (spaces) within which are oogonia, antheridia or both

101. Fucus Life Cycle

102. Chloroplast of Fucus

103. Fucales: PelvetiopsislimitataPloidy: 2NLife History: Gametic meiosis forms gametes which fuse to form a diploid zygote that grows into the adult plant

104. Melanosiphonintestinalis

105. Ralfsia- Dark brown or yellowish brown

106. Scytosiphonales: Petalonia fasciaPloidy: N(crusts are diploid sporophytes)Life History: SporicOther: Growth is diffuse

107. Scytosiphonales: ScytosiphonlomentariaPloidy: N (crusts are diploid sporophytes)Life History: SporicOther: growth is diffuse

108. Laminariales: SaccharinalatissimaPloidy: 2N Life History: SporicHeteromorphic, with microscopic filamentous gametophytes

109. Laminariales: NereocystisluetkeanaPloidy: 2NLife History: Sporicheteromorphic with microscopic filamentous gametophytes

110. Sieve elements of NereocystisSieve elements are elongated cells located with in the medulla

111. their cross-walls have fields of pored with plasmodesmata