Question

Example of chryophytes dinoflagellates euglinoids slime mould protozoans

Answer 1

Chrysophytes

Two types :-

1. Diatoms

• They are chief producer in ocean.
• They pile up at the bottom of water reservoirs and form a mountain like structure called diatomaceous earth.
• They are microscopic unicellular organism.
• The body is mainly made up of silica.
• The cell wall has two overlapping halves like soap case.
• They do not have flagella.
• large central vacuole is present.
• pigments- chlorophyll a,c & fucoxanthin(brown). Chlorophyll b is absent.
• Stored food - oil and leucin.
• Reproduction by binary fission (mostly).
• Eg.- Navicula

2. Golden Algae

• They are usually found in fresh water.
• Mostly green in colour.
• Unicellular.
• Sexual reproduction by conjugation.

Dinoflagellates

• Mostly marine.
• Photosynthetic.
• They appear yellow, green, brown, blue or red.
• They have two flagella attached to their body. Both are present at right angle to each other.
• Cell wall is made up of cellulose.
• Some of them produce toxins.
• Some dinoflagellates like Nautiluca & Procystis show bioluminescence.
• Nucleus is large and is called mesokaryon (histone absent).
• They posses an osmoregulatory organelle called pichle which looks like a contractile vacuole.
• Reproduction- asexual by cyst formation and zoospore.
• Stored food - starch & oil.
• Eg. - Ceratium

Euglenoids

• Habitat - fresh water and damp soil.
• It is unicellular, flagellate protist.
• Body is covered with a thin protein layer called pellicle which makes their body flexible.
• Cell wall absent.
• They have two flagella.
• locomotion by creeping movement.
• They are autotrophic in presence of sunlight and become heterotrophic in the absence of it.Hence, the mode of nutrition is called mixotrophic.
• Pigment - chlorophyll a & b
• Stored food - carbohydrate.
• They reproduce by longitudinal binary fission.
• Sexual reproduction absent.
• It is connecting link between plant and animal .
• Eg. - Euglena