Ascomycetes Consist of sporangial sac called ascus. Asci (singular-ascus) may occur freely or get aggregated with dikaryotic mycelium to form the fruitification called ascocarps.

The fruitification formed by asci are like

(i) Apothecium is a cup like structure, e.g., Peziza.

(ii) Perithecium flask shaped, e.g., Neurospora.

(iii) Cleistothecium closed with a slit, e.g., Penicillium

On the basis of locomotary organ Trypanosoma is included under flagellated protozoans. It resembles Protista on the basis of following characters

(i) Possess unicellularity.

(ii) Possess asexual reproduction, i.e., by binary fission.

(iii) Possess centrally located nucleus and also contain an prominent nucleus endosome.

(iv) Reserve food material is in the form of granules, such characters possessed by Trypanosoma made it to be included under kingdom-Protista.

Role of Fungi

Fungi are cosmopolitan in occurrance being present in air, water, soil over and inside animals and plants. The branch of biology dealing with the study of fungi is known as Mycology.

(i) Few fungi are used as nutritious and delicious food. e.g., Agaricus compestris

(ii) Saprophytic fungi lives upon dead organic matter and breaks complex substances into simple ones, that are absorbed by plants as nutrients.

(iii) Some fungi like Absidia, mucor and Rhizopus possess soil binding properties and make the soil good for cultivation.

(iv) They also provide pest resistence, e.g., Empusa, Ferinosa, etc.

(v) Yeast (Saccharomyces) has the property of fermentation, thus used in alcohol and dough preparation.

Algae and their spores exhibit enormous diversity and they vary greatly in their level of specialisation. Asexual reproduction by spores and their types are described below

(a) By Zoospores These are mobile flagellated spores. In which protoplasm of each vegetative cell undergoes repeated longitudnal division either into 2 or 4 rarely 8 or 16 daughter protoplast. The parent cell loses its flagella, before the onset of division.

After the last series of division, each daughter protoplast secretes a cell wall and neuromotor apparatus that develops two flagella, eyespots and contractile vacuoles.

Thus, each of the daughter cell formed resembles the parent cell in all aspects except the small size.

Formation of zoospores is very common under favourable conditions.

(b) By Aplanospores These are the non-motile spores. They are asexually formed with in a cell, in this the protoplast withdraws itself from the parent wall, rounds up and develops into aplanospores which may either germinate directly or may divide to produce zoospores.

(c) In this, the protoplasm withdraws from the cell wall, rounds up an develop a thick wall under unfavourable condition. These resting spores are called as hypnospores. They are red in colour due to presence of haematochrome. e.g., Vaucheria, Ulothrix.

(d) Akinetes These are special vegetative thick walled cells present in the filaments which remain under dorment state and return to germination under favourable condition and can also with stand unfavourable condition as Spirogyra.

(e) Statospores This are thick walled spores produced in diatoms.

(f) Neutral Spores In some algae, the protoplast, of vegetative cells directly functions as spores called as neutral spores (e.g., Ectocarpus).

All photosynthetic organisms contain one or more organic pigments that are capable of absorbing visible radiations, which will initiate the photochemical reaction of photosynthesis. Three major classes of pigments found in plants and algae are the chlorophylls, the carotenoids and the phycobilins.

Carotenoid and phycobilins are called accessory pigments since, the quanta (packets of light) absorbed by these pigments can be transferred to chlorophyll.

The diversity of light harvesting pigments in alga implies that the common ancestor was primitive and that no close affinity exist between blue, green, red, brown, golden brown and green algae, to use their common names.

The characteristic pigments of different classes are mentioned below