Question

6. Observe and identify body symmetry of
given animals (i) Asymmetry (ii) Radial (iii) Bilateral ​

Answer 1

star fish have radial symmetry.

humans have bilateral symmetry.

sycon have asymmetry.

Answer 2

Asymmetrical Symmetry:

• In some animals there are not any body axis and no plane of symmetry, thence the animals are known as asymmetrical. The rhizopod forms (e.g., Amoeba) and lots of sponges have ir­regular growth pattern of the body and can­not be divided into 2 equal halves.

Radial Symmetry:

• In symmetry the body are often divided into 2 roughly equal halves by anybody of the many vertical planes passing through the central axis just like the spokes of a wheel. The animals that exhibit prima­rily symmetry are cylinder in kind and also the similar components of the body are organized equally round the axis. The axis extends from the centre of the mouth to the centre of the aboral facet.

• The symmetry is seen among the sessile and inactive animals like in some sponges, hydroids, coelenterate pol­yps, medusae and ocean stars.

Bilateral Symmetry:

• In bilateralism the body components are organized in such how that the animal is dissociable into roughly alikeness halves through one plane (mid mesial plane) solely

• This plane passes through the axis of the body to separate the 2 halves that are remarked because the right and left halves.