What is difference between grades of body organization and symmetry of body of animals
Answers
Answer:
a. Body Organization
i. Body organization of unicellular animals is referred as ‘Protoplasmic grade’ organization.
ii. In case of multicellular animals, if tissues are not formed, their body organization is called as ‘Cellular grade organization’. Ex. Phylum-Porifera.
iii. In case of some animals, cells come together to form tissues with the help of which all the body functions are performed. Such animals show ‘Cell - tissue grade’ organization. Ex. Animals from phylum- Cnidaria.
iv. Flat worms show ‘Tissue-Organ grade’ organization. In this type of organization, tissues are organized to form some organs. However, complete organsystems are not formed.
v. Remaining all animals show ‘Organ-system grade organization’ in which different organs are joined together to form organsystem that performs specific functions. Ex. Crab, Frog, Human, etc.
b. Body symmetry
vi. In imaginary sense, if body of any animal is cut through imaginary axis of body, it may or may not produce two equal halves. Depending upon this property, there are different types of animal bodies.
vii. Asymmetrical Body: In case of such body, there is no any such imaginary axis of the body through which we can get two equal halves. Ex. Amoeba, Paramoecium, some sponges.
viii. Radial symmetry: In this type of body, if imaginary cut passes through central axis but any plane of body, it gives two equal halves. Ex. Star fish.
x. Bilateral symmetry: In this type of body, there is only one such imaginary axis of body through which we can get two equal halves. Ex. Insects, fishes, frog, birds, human, etc.