WORLD OF ALGAE

• Eukaryotic algae has same intracellular organization in higher green plants such as presence of organelles.
• Eukaryotic algae are characterized with the absence of vascular

  tissues (xylem and phloem) and are not differentiated into roots, stems, or leaves.
• Eukaryotic algae has chlorophyll as its main photosynthetic pigment and also has the same accessory pigments as cyanobacterias.
• Eukaryotic algae are under the class Rhodophyceae and division Rhodophyta.
• Eukaryotic algae are called red algae due to their bright pink to red color caused by the phycobiliproteins, phycoerythrin.
• Pyrrophyta (Dinoflagellates)
• Chrysophyta (Diatoms)
• Phaeophyta (True Brown Algae)
• Euglenophyta is one of the pigmented algae.
• Chlorophyta (Green Algae)
• Algae reproduction may occur through vegetative (division of cells, fragmentation of colony), asexual by production of spores or sexual through union of gametes.
• Vegetative and asexual reproduction enables fast production of new individuals of stable adapted genotypes while sexual reproduction allows variation but is more costly due to wasted gametes being failed to fertilize.
• Life Cycles of Algae:

  1. Haplontic or Zygotic Life Cycle
  2. Diplontic or Gametic Life Cycle
  3. Diplohapontic Life Cycle
• Haplontic or Zygotic Life Cycle – Vegetative phase is predominant; haploid in nature; meiosis occurs during zygote germination.
• Diplontic or Gametic Life Cycle – characterized with single predominant vegetative diploid phase; meiosis leads to formation of haploid gametes
• Diplohaplontic Life Cycle- introduces alternation of generation between haploid gametophyte and diploid sporophyte phase. Gametes are produced by gametophytes via mitosis while spores are created by sporophyte via meiosis
• Most red algae exhibit a triphasic life cycle: a gametophyte (n), carposporophyte (2n) and tetrasporophyte (2n).
• Red algae has complete absence of flagella and centrioles in any stages of any species.
• Red algae also has absence of sexuality in some members
• Red algae lacks plasmodesmata and presence of pit connections in some members.
• Red algae has thylakoids that are unstacked and are group into

  phycobilisomes same with the cyanobateria.
• Bangiophycidae and Florideophycidae under the division Rhodeophyta consist of unicellular forms, uninucleated cells, absence of pit connections in most members, and characterized by the absence of true sexual means of reproduction in some members
• Under Division Rhodophyta, there is only one class, Class Rhodophyceae
• There are 2 subclasses under Rhodophyceae, subclass Florideophycidae and Bangiophycidae
• Under subclass Bangiophycidae, Order Porphyridiales, Order Bangiales, and Order Compsopogonales.
• Under Order Porphyridiales is Family Porphyricidiaceae and an example of a species under this family is Porphyridium cruentum
• Under Order Bangiales is Family Bangiaceae and an example of a species under this family is Porphyra sp.
• Under Order Copsopogonales is Family Comsopogonaceae and a species under this family is Composopogon caeruleus
• Under subclass Florideophycidea, there are four orders, Order Nemaliales, Order Gracilariales, Order Gigartinales and Order Ceramiales
• Order Nemaliales

  Family Galaxauraceae (Galaxaura sp.)

  ▪ Order Gracilariales

  Family Gracilariaceae (Gracilaria sp.)

  ▪ Order Gigartinales

  Family Solieriaceae (Eucheuma sp.)

  ▪ Order Ceramiales

  Family Rhodomelaceae (Polysiphonia sp.)
• The dinoflagellates are unicellular protists, so called due to the usual biflagellated nature of the vegetative cells.
• The flagella, which are different from one another, in terms of form, orientation and type of movement, could be inserted anteriorly laterally.
• Members of this group belong the division Pyrrhophyta and two

  classes, i.e., Desmophyceae and Dinophyceae.
• Desmophyceae has apically inserted flagella while Dinophyceae has

  laterally inserted flagella or at the median section of the cell body; one at the cingulum and the other at the sulcus or the longitudinally oriented groove.
• Common mean of reproduction is by asexual method through simple binary fission however, sexual means can occur through either by isogamy or anisogamy.
• (Pyrrophyta) Some of the bloom-forming species have the capacity to encyst under unfavourable conditions. The form of the cyst is very different from the vegetative cell and considered a taxonomic character.
• During warm months of summer, Pyrrophyta may reproduce greatly hence water water appear golden or red, hence “red tide”.
• Marine life such as fishes and shellfish, clams, mussels, and oysters are affected because of the neurotoxins produced by dinoflagellates which also harms the consumers.
• Representative species of Pyrrophyta are Pyrodinium bahamense, Prorocentrum, Ceratium
• The diatoms are classified under the division Chrysophyta and class

  Bacillariophyceae.