Question

What are sarcodines? Describe their structure.

Answer 1

Phylum protozoa is the third largest phylum of the kingdom Animalia. The protozoans are termed as cellular by Dobell because they have one celled body which performs all the biological activities like multicellular animals. Protozoans were first studied by Leeuwenhoek and the name protozoa was coined by Goldfuss. Study of protozoans is known as Protozoology.

Complete solution:
Protozoans are small microscopic, Eukaryotic Unicellular, colourless, spherical, oval,bell shaped, spindle shaped, slipper-like having irregular symmetry.
Body level of Protozoans is Protoplasmic level. Their protoplasm is uninucleate or multinucleate.
Protozoans are divided into 4 classes based on locomotory organs and nucleus apparatus.
1. Mastigophora
2. Sarcodina or Rhizopoda
3. Sporozoa
4. Ciliophora
Sarcodines: These are protozoans belonging to the class sarcodina. They are free floating or bottom dwellers in Fresh or marine water and few are parasites.
Structure of sarcodines:
Body: Their body is without periplast, few with Ca and Si shell.
Nucleus: Uninucleate/binucleate or multinucleate(monomorphic)
Cytoplasm:Differentiated into Ecto and endoderm.
Contractile vacuole: Present in fresh water organism and not in parasite or marine form.
Locomotion: Temporary protoplasmic out growth pseudopodia.
It is of various types eg 1. Lobopodia(finger like) - Amoeba 2. Filopodia (thread like)- Euglypha 3. Reticulopodia (Raticulae, branched)- Globigerina 4. Axopodia (with axial support)- Actinophrys
Nutrition: Holozoic
Reproduction: Asexual- binary/multiple fission

Note-
Sarcodines is further divided into three classes- 1. Amoeboids- eg Amoeba (simple), pelomyxa- chaos chaos (large and multinucleated amoeba), Entamoeba histolytica ( parasite in colon of man causes Amoebic dysentery). 2. Radiolarians- marine, silica skeleton, axopodia or filopodia.eg Acanthometra, colozoum 3. Foraminifera- marine or freshwater, reticulopodia present, shell is Calcareous eg.a.Elphidium, globigerina.