ADVERTISEMENTS:
Learn about the comparison among Amoeba, Euglena and Paramoecium.
Comparison # Amoeba:
1. Amoeba lives in freshwater ponds and streams.
ADVERTISEMENTS:
2. Morphology of Amoeba:
(a) Shape:
Irregular
(b) Size:
ADVERTISEMENTS:
About 0.25 mm in diameter
(c) Limiting membrane:
Plasmalemma—thin and elastic.
(d) Cytoplasmic differentiation:
Ectoplasm clear and non-granular compared to endoplasm.
(e) Cytoplasmic inclusions and organelle:
Grains of sand and granules which are protein and fat in nature. Single round contractile vacuole, food vacuoles and water vacuoles.
(f) Nucleus:
Single, lodged centrally in the endoplasm.
ADVERTISEMENTS:
3. Physiology of Amoeba:
(a) Locomotion:
By protrusion of finger like projections, called Pseudopodia, movement is called Amoebiod movement.
(b) Nutrition:
ADVERTISEMENTS:
Holozoic Diatom, bacteria, small protozoa serve as food. Food is digested in temporary food-vaeuoles. Undigested food particles are thrown out.
(c) Respiration:
O2 dissolved in water enters the body by diffusion.
(d) Excretion:
ADVERTISEMENTS:
Large part of excretory matters in the form of urea and CO2 pass out through general body surface.
(e) Reproduction:
Binary fission is the usual mode. Cyst formation in unfavourable condition.
(f) Response to stimuli:
ADVERTISEMENTS:
React to various kinds of stimuli—namely contact, heat, electricity, light, chemicals, etc.
Comparison # Euglena:
1. Euglena lives in freshwater ponds and streams and prefers to stay in surface water.
2. Morphology of Euglena:
(a) Shape:
Fixed, spindle-shaped, anterior end broad and posterior pointed.
(b) Size:
ADVERTISEMENTS:
40-65 µ along the long axis.
(c) Limiting membrane:
Pellicle—thin, elastic and bears parallel thickening running obliquely.
(d) Cytoplasmic differentiation:
Ectoplasm is less dense than the endoplasm.
(e) Cytoplasmic inclusions and organelle:
ADVERTISEMENTS:
Stored reserve includes lipid and paramylum, chlorophyll bearing ‘chromatophores’ of variable sizes and number. Cytostome funnel-shaped and situated at the anterior end, a gullet joins it to a reservoir into which opens minute contractile vacuoles. Food vacuole usually absent, a single active flagellum and stigma.
(f) Nucleus:
Single oval nucleus situated a little below the middle line of the body.
3. Physiology of Amoeba:
(a) Locomotion:
Swims in water in a spiral path with the help of flagellum. It may show ‘Euglenoid movement’ in which waves of contraction pass along the body- like peristaltic movement.
(b) Nutrition:
Holophytic—it can manufacture its own food. Holozoic and saprophytic modes of nutrition are also exhibited.
(c) Respiration:
Same as in amoeba.
(d) Excretion:
CO2, urea passes out through general body surface.
(e) Reproduction:
Longitudinal binary fission is the mode. Binary fission in cyst condition is also encountered.
(f) Response to stimuli:
React to various kinds of stimuli.
Comparison # Paramoecium:
1. Paramoecium lives in freshwater ponds and streams.
2. Morphology of Paramoecium:
(a) Shape:
Fixed, cigar-shaped, anterior end broad and posterior end pointed.
(b) Size:
Can be seen with naked eyes. 0.25 mm along the long axis.
(c) Limiting membrane:
Pellicle—thin, elastic and with pores for the emergence of cillia.
(d) Cytoplasmic differentiation:
Ectoplasm non-granular and bears ‘Trichocysts’, endoplasm denser in nature.
(e) Cytoplasmic inclusions and organelle:
Reserve food is the only cytoplasmic inclusion. An oral groove leads into the cytopharynx or gullet. A pair of star-shaped contractile vacuole, one each at the anterior and posterior end. Food vacuoles one to many, temporary cell anus and many cilia round the body.
ADVERTISEMENTS:
(f) Nucleus:
Dimorphic, a bean- shaped macronucleus and a small round micronucleus.
3. Physiology of Paramoecium:
(a) Locomotion:
Swims in water in a zig-zag fashion with the concerted beating of cilia.
(b) Nutrition:
Holozoic. The cilia help in drawing food particles in the gullet. Digestion in temporary food-vacuoles. Presence of cytopyge or temporary cell-anus for egestion.
(c) Respiration:
Same as in amoeba.
(d) Excretion:
CO2, urea passes out through general body surface.
(e) Reproduction:
Asexual reproduction by transverse binary fission. Sexual reproduction by conjugation. No cyst formation.
(f) Response to stimuli:
React to various kinds of stimuli.
