Apicomplexans and Dinoflagellates

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Apicomplexans :

(i) Habitat:

Apicomplexans are a large group of parasitic protozoans some of which cause serious diseases such as malaria in humans.

(ii) Locomotion:

Apicomplexans have no specific structures for locomotion but move by flexing.

(iii) Spore Formation:

At some stage in their lives, they develop a spore. It acts as a small infective agent which is transmitted to the next host.

(iv) More than One Host:

Many organisms of this group spend part of their life in one host and part in a different host species.

(v) Life Cycle of Plasmodium:

Plasmodium (that causes malaria), enters human blood through the bite of an infected female Anopheles mosquito.

Plasmodium first enters liver cells and then red blood cells, where it multiplies.

when each infected red blood cell bursts, many new parasites are released.

The released parasites infect new red blood cells. The process is repeated.

When millions of red blood cells burst simultaneously, the symptoms of malaria appear.

Chill, followed by high fever are the symptoms of malaria. These are due to toxic substances that are released and affect other organs of the body.


Dinoflagellates (Phyrrophyta):

These are the most unusual protists because of the following characters:

(i) Unicellular:

Most dinoflagellates are unicellular.

(ii) Shell:

Their cells are often covered with, the shells of interlocking cellulose plates impregnated with silicates.

(iii) Second Group Producers:

In the marine ecosystem they are second most important group of producers (first group is diatoms).

(iv) Photosynthetic Pigments:

They have chlorophyll a and c. They contain carotenes and fucoxanthin.

(v) Population Explosions or Blooms:

They have rarely population explosions or blooms. These blooms colour the water orange, red or brown and are called as red tides.

Examples:

Gonyaulax, Ceratium.

Apicomplexans and Dinoflagellates Apicomplexans and Dinoflagellates Reviewed by SaQLaiN HaShMi on 5:49 AM Rating: 5

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