CLASSIFICATION OF ALGAE

BY JERSON PANOPIO

In this classification, Fritsch classified all the algae in to 11Classes as follows:

Chlorophyceae Xanthophyceae Chrysophyceae Bacillariophyceae Crytophyceae

Dinophyceae Chloromonadineae Euglenineae Phaeophyceae Rhodophyceae Myxophycea or

Cyanophyceae

FELIX EUGENE FRITSCH

April 26, 1879 – May 23,1954 He was educated at6 University of

London at the University Of Munich. He taught several places in London. He is well known algalogist He wrote of books of algae His book entitled The structure and

Reproduction of Algae.

A different system of algal classification has been proposed by Pasher.

The system were classified into 8 Division as follows:

1. Chrysophyta2. Phaephyta3. Pyrrhophyta 4. Euglenophyta5. Chlorophyta6. Rhodophyta7. Charophyta8. Cyanophyta

BACILLARIOPHYTA

are the diatoms. characterized by a silica shell of often

intricate and beautiful sculpturing. Most diatoms exist singly, although

some join to form colonies. They are usually yellowish or brownish,

and are found in fresh- and saltwater, in moist soil, and on the moist surface of plants.

Fresh-water and marine diatoms appear in greatest abundance early in the year as part of the phenomenon known as the spring bloom, which occurs as a result of the availability of both light and (winter-regenerated) nutrients.

They reproduce asexually by cell division.

BACILLARIOPHYTA

CHAROPHYTA

are freshwater plants and generally grow anchored to the substratum by rhizoids with a shoot extending upward.

reproductive structures develop at these nodes and are, along with the biflagellate sperm produced in the male gametangium, quite similar to those of mosses.

CHAROPHYTA

CHLOROPHYTA

division of the kingdom of protista consisting of the photosyntetic organism commonly known as green algae.

are largely aguatic or marine, a few types are terrestrial, occurring on moist soil, on the trunks of trees, on moist rocks and in snow banks.

Various species are highly specialized .

CHRYSOPHYTA

: large group of eukariotyes algae commonly called golden algae.

found mostly in freshwater. the cell walls are composed of cellulose

with large quantities of silica. they contain the photosynthetic

pigments chlorophyll.

CYANOBACTERIA

phylum of prokaryotic aguatic bacteria that obtain their energy through photosynthesis.

They are often referred to as blue-green algae, even though it is now known that they are not related to any of the other algal groups, which are all eukaryotes.

may be single-celled or colonial. Cyanobacteria have no one habitat because

you can find them almost anywhere in the world.

DINOPHYTA

large group of flagellate protistis Some species are heterotrophic, but many are

photosynthetic organisms containing chlorophyll.

Other dinoflagellates are colorless predators on other protozoa, and a few forms are parasitic.

Reproduction for most dinoflagellates is asexual, through simple division of cells following mitosis.

The dinoflagellates are important constituents of plankton, and as such are primary food sources in warmer oceans.

PHAEOPHYTA

consisting of those organisms commonly called brown algae.

the chrysophytes brown algae derive their color from the presence, in the cell chloroplasts, of several brownish carotenoid pigments, as fucoxathin.

brown algae are marine, growing in the colder oceans of the world, many in the tidal zone, where they are subjected to great stress from wave action; others grow in deep water.

Diversity in form and structure

Algae are amongst the most diverse organism in the plant kingdom.

They are also found in the atmosphere, and as sub – aerial, terrestrial, Epiphytic (on plant) ,epizoic (on animals), epipelic (on mud), epipsammic (on sand), cryophytic (at low temperature), thermophilic (requiring high temperature for growth), halophilic (salt loving).

They can also form symbiotic associations with a number of organisms including.

Fungi (as symbionts in lichen thalli) Bryophyte (endophytes in the thallus) Pteridophytes (endophytes in the

leaves of Azolla) Gymnosperms (as endophytes in the

corroloid roots of Cycas) Angiosperm ( as parasites) And corals.

The distribution of such algae on the side of the stones and rocks that not facing in the current of water, shows their wisdom/ adaptation in carefully choosing their dwelling place to avoid being carried away.

Algae also occur.

Single celled individuals Organized colonies Simple filaments without polarity Simple unbranched filaments showing

differentiation into a distinct base Branced filaments Heterotrichous thalli made up of two

sets of filaments.

Parenchymatous thalli generally two cells thick forming broad flat structure.

Siphonous thalli made up of numerous elongated cells.

Structure of the algal cell.

there is no uniform pattern for describing an algal cell. A few characters such as cell wall, the plastids, the photosynthetic pigments, the storage product and the flagellate.

The following feature bring out some aspects of the diversity in the structure of the algal cell.

The algal cell is bounded by a defined cell wall.

The protoplasm within the cell is differentiated in all the eukaryotic algae and different organellse can be recognized.

A pyrenoid is another structure which can be easily recognized within the cell.

Eyespots and contractile vacuoles are usually present in the flagellated forms.

Most eukaryotic algae have uni – nucleate cells.

REPRODUCTION IN ALGAE

NARDO BERNARDO MOLA

The survival of all living organisms depends on reproduction. Every species must be able to reproduce, because if stopped reproducing it would disappear from the planet when the present members died. Algae are no exception to this fundamentals.

All organism have developed mechanism for reproduction.

There are two main kind of reproduction. Sexual reproduction – a new organism

is formed when two sex cells unite during the process of fertilization

Asexual reproduction – a new organism is formed by the participation of only one individual. Fragments/parts/cells, etc. of the parent individual have the capacity to develop into new individual during the asexual reproduction.

Algae exhibit diverse pattern of reproduction, both sexual and asexual. Most algae show variety ways for asexual reproduction.

Unicellular algae reproduce since it is much more simpler when compared to sexual reproduction.

Unicellular algae reproduce by mitosis or cell division.

Multicellular algae are also able to reproduce asexually, but not by simple cell division.

Fragmentation – fragments or parts of a multicellular alga separate from the individual and develop into completely new individual.

Sometimes referred as vegetative reproduction because the vegetative part of the organism has been able to propagate the species.

Different types of sexual reproduction have been recognized in the algae.

Isogamous – simplest type where the two fusing gametes are identical and cannot be differentiated as male or female.

Two gametes may be similar in their size, but they may differ in their behavior , one gamete may be more active and other may be less active or two gametes may differ slightly in their size, but may differ in their behavior of the gamete resulting to anisogamous sexual reproduction.

Oogamous’ sexual reproduction – the two gametes differ both in their structure as well as in their functions so that one gamete can be recognized as male and the other as female.

Conjugation – a special type of reproduction. The entire cell serve as a gametes and the cell content are transported passively between two cells taking part in sexual reproduction.

Lateral conjugation – when two cells are from the same filament then the sexual reproduction.

Scalariform conjugation – two cells are from different filaments lying parallel to each other.