Phylum Bacillariophyta, Xanthophyta & Chrysophyta

Bacillariophyta is a phylum of the kingdom Protista, consisting of mostly unicellular aquatic algae commonly referred to as Diatoms.
Xanthophytes are the yellow-green algae whereas Chrysophytes are the golden-brown algae.

1. Phylum Bacillariophyta Diatoms Presented by: Fasama Hilton Kollie Lecturer, Department of Biology Mother Patern College of Health Sciences February 28, 2019

2. Lesson Outline Overview of the phylum Bacillariophyta, Xanthophyta and Chrysophyta General characteristics of diatoms, yellow-green algae and golden brown algae

3. Lesson Objectives Upon completion of this topic, students will be able to; D escribe diatoms, xanthophytes and chrysophytes Identify the similarities and difference among chromist

4. Phylum Bacillariophyta: Diatoms Bacillariophyta is a phylum of the kingdom Protista, consisting of mostly unicellular aquatic algae Diatoms Diatoms are a major group of microalgae, and are among the most common types of  phytoplankton About 5,600 extant species

5. General Characteristics Diatoms occur in fresh water, salt water and in moist vegetation on land Some species are attached to substracts , others are free swimming Most live  pelagically  in open water, although some live as surface films at the water-sediment interface (benthic)

6. General Characteristics Cont’d… Diatoms generally are formed in two general shapes Centric diatoms Pennate diatoms Pennate Centric

7. General Characteristics Cont’d… Cells are surrounded by a rigid two part box like cell wall composed of silica, called   frustule  It’s elaborate, with ornamental patterns and numerous tiny pores, Composed of silica (silicon dioxide, SiO 2 ) Reproduce asexually

8. Phylum Xanthophyta Yellow-Green A lgae

9. Phylum Xanthophyta : Yellow-Green Algae D ivision of algae commonly known as  yellow-green algae Consist of appx. 600 species of algae most of which inhabit fresh water They vary in form and size from single-celled organisms to small filamentous forms or simple colonies Colonia form Filamentous form

10. General Characteristics Mostly found in fresh water some in marine environment or damp soil They consist of both free living and solitary organisms

11. General Characteristics Cont’d… Chlorophyll a and c Xanthophyll (dominant pigments) Unicellular Some species also exist as colonies or as long filaments of cells Other are Coenocytic Consisting of a single cytoplasmic mass that contains many nuclei Colonia form Filamentous form

12. Coenocytic:

13. General Characteristics Cont’d… Xanthophyte cell walls consist of  Cellulose  and  Hemicellulose

14. General Characteristics Cont’d… Most have two flagella arising from opposite ends of the cell Motile cells with a forwardly directed tinsel flagellum and a posteriorly directed whiplash flagellum Some species of xanthophytes serve as a model system for investigating chloroplast movement

15. Reproduction In Yellow-Green Algae Reproduction is predominantly asexua l which involves fragmentation of filaments or spore formation Spores may be flagellated and free-swimming (zoospores), or they may be non-flagellated

16. Reproduction Cont’d… Sexual reproduction is known only in two genera:  Botrydium , in which the sex cells are isogamous , and  Vaucheria , in which the cells are oogamous Botrydium granulatum Vaucheria

17. Phylum Chrysophyta Golden-brown Algae

18. Phylum Chrysophyta: Golden-Brown Algae Unicellular organisms assigned to the class Chrysophyceae Many have characteristics gold color (Greek chrysos , “ gold ” and phyto , “ plant ) Appx. 1,000 species Mostly freshwater and marine planktonic algae Free swimming and colonial organisms Synura Fig. 1.0 Dinobryon

19. General Characteristics Cont’d… Chlorophyll a , c and fucoxanthin There is no common cell structure Autotrophs Characterized by the use of oil droplets as a food reserve or Polysaccharide laminarin Synura

20. General Characteristics Cont’d… The formation of a dormant spores in golden-brown algae serve as their hallmark feature Statospores (statocyst) These spores are encased in a wall made of silica It contains Nucleus, Chloroplast, Basal bodies, Golgi apparatus, many Mitochondria and Ribosomes

21. Reproduction Sexual reproduction is rare Asexual reproduction is common This is by the formation of motile and nonmotile spores and by cell division

22. 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 Chrysophyta. The Columbia Encyclopedia , Sixth Edition. 2001. Copyright 2004 Columbia University Press. Introduction to the Chrysophyta. UCMP-Berkeley

23. “ The most valuable thing a teacher can impart to student is not knowledge and understanding but a longing for knowledge and understanding, and an appreciation for intellectual values, whether they be artistic, scientific, or moral. ” Albert Einstein