Archaebacteria: These are a group of ancient bacteria, which continue to live under conditions that resemble those of the primitive earth.
Holozoic Nutrition: The mode of nutrition shown by animals, where they ingest particulate food is called holozoic nutrition.
Eukaryotes: Those organisms with true nucleus(with a membrane boundary) in their body cells are called eukaryotes.
Prokaryotes: Those organisms without a true nucleus(includes not bounded by a membrane) and membrane bound organelles in the cell, are called Prokaryotes.
Trinomial Nomenclature: The scientific name of organism, especially animals, has occasionally three names. They are generic name, the specific name and the sub-specific name.
Cell: Cell is the structural and functional unit of life.
Prokaryotic cell: A cell which has an incipient nucleus and lacks membrane bound organelle, is called a prokaryotic cell.
Dicotysomes: In plant cells, the Golgi apparatus is present in the form of unconnected units, called Dicotysomes.
Cell wall: Cell wall is a protective covering, outer to plasma membrane in plants, bacteria, fungi and some protists.
Acellular organism: Acellular organism is one that exhibits protoplasmic level of organisation i,e their body is made of mass of protoplasm not differentiated into cells. It is also called Non-cellular. example-Protozoans.
Triploblastic animals: An animal with three layers in its body wall, namely an outer Ectoderm, middle Mesoderm and an inner Endoderm.
Pseudocoelome: The space between digestive tract and body wall encloses a cavity which is not lined by mesodermal epithelial layer. Example- Round Worm.
A coelome: The space between the digestive tract and body wall is filled with parenchymatous tissue derived from mesoderm and hence a clear cavity is absent. Such a condition is called Acoelome.
Eucoelome: The body cavity present between the digestive tract and body wall is lined with mesodermal epithelial layer called outer somatic and inner Splachnic layer. Such a cavity is known as Eucoelome. Example- Earth worm.