Page 3 - 11-Bio-7 The Kingdom protista

7. The Kingdom Protista (or protoctista) eLearn.Punjab

Fig 7.1 The kingdom protista includes such diverse species as (a) single celled ciliated protozoan, (b) giant brown algae (kelps) and (c)
slime molds.

DIVERSITY AMONG PROTISTA

During the course of evolutionary history, organisms in the kingdom protista have evolved diversity
in their (a) size and structure, (b) means of locomotion, (c) ways of obtaining nutrients, (d) interactions
with other organisms, (e) habitat and (f) modes of reproduction. Diversity is exhibited by all of the
major protist groups (Fig. 7.1).

Based on the diversity, most biologists regard the protists kingdom as a polyphyletic group of
organisms; that is, the protists probably do not share a single common ancestor. Margulis and
Schwartz have listed 27 phyla to accommodate this diverse assemblage of organisms.

MAJOR GROUPS OF PROTISTA

1. Protozoa : Animal - like Protists

All protozoans are unicellular. Most ingest their food by endocytosis. A summary of protozoan
diversity is given in Table 7.1.

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