Page 81 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

Phylum Euglenophyta (f) They have eye spot for detection of

This phylum consists of unicellular light intensity.
aquatic organisms most of which live (g) They are eukaryotic cells.
in freshwater and possess flagella. (h) They possess both plant and
FOR ONLINE READING ONLY
Euglena sp.is an example of organisms animal characteristics. The plant
found in this phylum. Figure 5.10 characteristic is the possession
shows the structure of Euglena sp. of chloroplasts which contain

chlorophyll for photosynthesis. The
Flagellum animal characteristics include ability
Gullet to move using a flagellum, presence

of an eyespot for detection of light
Eyespot intensity, and presence of gullet for
ingesting food.

Nucleus
Chloroplast Advantages of Euglena sp.
Contractile (a) They are used for sewage treatment
vacuole due to their heterotrophic mode of
nutrition.
(b) Euglena sp. is an important source
of food to aquatic organisms, such
Pellicle
as fish.

Figure 5.10: Structure of the Euglena sp. (c) During photosynthesis, Euglena sp.
produce oxygen gas. This oxygen
Characteristics of Euglena sp. is useful to aquatic organisms. It
(a) They are unicellular. also helps to balance oxygen gas

(b) They have chloroplasts which contain levels in sewage treatment plants.
chlorophyll for photosynthesis.
(c) Most of them are found in freshwater; Disadvantages of Euglena sp.
Euglena sp. blooms can be harmful
only a few are found in salt water. to fish. The toxins produced by some

(d) They are protected by pellicle, Euglena species can kill fish and other
which surrounds the cytoplasm. aquatic organisms.
The pellicle allows the euglena to
change shape.
(e) They have flagella for movement.

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