KINGDOM :ANIMALIA (METAZOA)
LEVELS or GRADES OF ORGANIZATION:
Organization is the arrangement of smaller components any structure in to larger ones and so on in a hierarchy. In the animal kingdom Protozoans exhibit protoplasmic grade of organization.
Metozoans exhibit higher levels of organization such as :
Cellular grade of organization
Tissue grade of organisation
And Organ level of organization
1. ACELLULAR /PROTOPLASMIC GRADE OF ORGANIZATION:
1.Unicellular organisms like protozoans exhibit protoplasmic grade of organization.
2. All the like functions are confined within the boundaries of a single cell.
3. With in the cell, protoplasm is differentiated into organelles capable of performing specialized functions.
4. Division of labour is seen among the cell organells.
2.,CELLULAR GRADE OF ORGANIZATION:
1.cellular grade of organization is the lowest level at organization in the metazoans.
2. it is exhibited in the sponges.
3. individual cells differentiate during development to perform special functions.
4. Hence division of labour is seen among the cells.
5. Nerve cells and sensory cells are absent. Hence, different types of cells are functionally isolated. True tissues are absent.
6.cells are not strongly associated to perform a specific collective function.
3.TIsSUE GRADE OF ORGANIZATION( DIPLO BLASTIC ORGANIZATION):
1.Chidarians (coelenterates) exhibit tissue grade of organization.
2. Nerve cells and sensory cells are present.
3. The cells, that are performing similar functions are highly coordinated and are aggregated in to tissues.
4.The functioning of different tissues is also coordinated.
5. The tissues are not assembled in to organs.
6.Embryonic ectoderm gives rise to the epiderms, the outer layer of the body wall.
7.Endoderm gives rise to the gastro dermis, the inner layer of the body wall that lines the gut.
8. Between the epidermis and gasrodermis a non cellular layer called mesoglea is present.
4. ORGAN –SYSTEM GRADE OF ORGANIZATION (TRIPLO BLASTIC ):
1.Triploblastic animals exhibit organ –system grade of organization.
2.All the tissues are derived from three germ layers, i.e : an outer – ectoderm, the middle – mesoderm, and an inner – endoderm
3.The evolution of mesoderm resulted in structural complexity.
4.The tissues assembled into larger functional units called organs.
5.Organs are usually composed of more than one kind of tissue and have a more specialized function than tissues.
6. Organs working together to perform one or more specific functions constitute an organ system.
7. organ systems are associated with the basic body functions.
8.Eleven different kinds of organ systems are observed in triploblastic metazoans. They are : integumentery,
and reproductive systems.
9.Highly specialized sensory cells are present. They bring about higher level of coordination and integration of the constituent tissues, organs, and systems.
10 Endocrine system, an another integrative system is present in higher triploblastic animals.