Department of Zoology at ANDC/Zoology Museum/Museum specimens/Kingdom Protista

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Kingdom Protista

Date & Time : 22, November 2017 01:46


General Characteristics of Protista

  • Protists are microscopic, unicellular and eukaryotic organisms.
  • Their size commonly range from 10 to 52 micrometers, but they can grow as large as 1 mm, and are seen easily by a microscope.
  • Many protists are free Living, found in fresh and salt water; but a number of protists are endoparasites causing pathogenic effects in their hosts.
  • Body is surrounded by a thin plasma membrane which may be covered by pellicle (a thin layer supporting the cell membrane).
  • They may be naked organisms or enclosed in a shell.
  • The cytoplasm is differentiated into an outer ectoplasm and inner endoplasm.
  • Protistans possess pseudopodia, cilia or flagella as the locomotory organelles.
  • Nutrition may be holophytic, holozoic, saprozoic or parasitic.
  • Respiration occurs by the diffusion of gases through body surface.
  • Reproduction may take place by asexual or sexual means.
  • Asexual reproduction takes place by the process of binary fission, multiple fission, sporulation or budding.
  • Sexual reproduction takes place by conjugation (syngamy), endomixis, automixis, cytomixis or hemixis.

A Few Examples

Noctiluca

SCIENTIFIC NAME- Noctiluca.

GEOGRAPHICAL DISTRIBUTION- Commonly found in madras, atlantic and pacific oceans
HABITAT-Marine and pelagic.

IDENTIFYING FEATURES-

  • large circular body measuring about 1-1.5mm in diameter.
  • body is covered by a stout pellicle.
  • A small flagellum and a long,stout tentacle is present.


COMMON CHARACTERS-

  • Mouth is elongated having a pouch like cytopharynx.
  • Nucleus is single and large.
  • Holozoic nutrition.
  • Cytoplasm is highly vacuolated and differentiated into ectoplasm and endoplasm.
  • Asexual reproduction by binary fission and spore formation.

Euglena

Euglena diagram

Geographical Distribution:

Euglena is cosmopolitan in distribution.

Habitat:

It is found in freshwater ponds,ditches,lakes and slow running streams rich in organic matter.

Labelled diagram of EUGLENA.jpg


Identifying Features:

  • It is oval,spindle shaped measuring about 50-100 microns in length.


  • Body is blunt anteriorly and pointed posteriorly.


  • Single whip like fllagelum arises from the base of reservoir.


  • Body is covered by striated and flexible pellicle.



Common Characters:

  • Anterior end of body bears a small funnel like cytostome and a tubular cytopharynx which leads into a large spherical reservoir.


  • Nucleus is large and spherical located toward the posterior region.


  • Cytoplasm is differentiated into ectoplasm and endoplasm.


  • Nutrition is holophytic or saprophytic.


  • Reproduction is asexual by binary fission.




Amoeba

Labelled diagram of AMOEBA.jpg

Geographical Distribution:

Found all over the world.

Habitat:
Amoeba proteus

Commonly found in mud, freshwater ponds, ditches, slow running streams.

Identifying Features:

  • Irregular shaped body(measuring about 0.25 mm-1 mm in diameter) appears like a colourless mass of protoplasm.
  • Body is covered by a thin, clear, elastic and semi-permeable plasma membrane called plasmalemma.


Common Characters:

  • Cytoplasm is distinguished into ectoplasm and endoplasm.
  • Endoplasm contains a spherical nucleus, a large contractile vacuole and various food vacuoles.
  • Locomotion by short and blunt pseudopodia.
  • Nutrition is holozoic.
  • Asexual reproduction by binary fission.


Paramecium

Labelled diagram of PARAMEcIUM.jpg

SCIENTIFIC NAME-Paramecium

COMMON NAME

HABITAT-Freshwater ponds,pools,ditches,streams,lakes,reservoirs and rivers.
Specially abundant in ponds rich in organic matter.


IDENTIFYING FEATURES-

  • Slipper shaped body about 0.3mm in length.
  • Cilia are uniformly arranged in longitudinal rows except at posterior end of the body.
  • On the oral side is a groove ,the oral groove or peristomial groove, running backwards obliquely to the right side of anterior end to about middle of the body.
  • This groove ends in mouth or cytostome.


COMMON CHARACTER-

  • Locomotion by lashing of cilia.
  • Body is covered y pellicle.
  • Cytoplasm is clearly distinguishale into ectoplasm and endoplasm.
  • Ectoplasm contains basal granules.
  • Endoplasm contains two nuclei(large macronucleus,small micronucleus),two contractile vacuoles and reserved food materials.
  • Nutrition is holozoic.
  • Asexual reproduction is by transverse binary fission,sexual reproduction is by conjugation,endomixis,autogamy and hemixis.



Vorticella


SCIENTIFIC NAME-
Vorticella

COMMON NAME

GEOGRAPHICAL DISTRIBUTION-Cosmopolitan in distribution.

HABITAT-Freshwater ponds , lakes , rivers , streams attached to some objects like weeds.

IDENTIFYING FEATURES-

  • Inverted bell shaped body with a long, slender stalk for attachment.
  • Rim of bell is thick and surrounded by cilia.
  • Cilia are arranged in two circles,in an outer anticlockwise fashion on the rim and in inner one on the edge of disc.


COMMON CHARACTERS-

  • Body consists of pellicle,ectoplasm and endoplasm .
  • Endoplasm contains a long horse shoe shaped macronucleus ,a small micronucleus,a single contractile vacuole and food vacuoles. medulla.
  • Free broad end of the body is oral and the opposite end is aboral.
  • Nutrition is holozoic.
  • Reproduction by binary fission and conjugation.