NEET BIOLOGY

Detailed explanation-1: -Asymmetry. Only members of the phylum Porifera (sponges) have no body plan symmetry. There are some fish species, such as flounder, that lack symmetry as adults. However, the larval fish are bilaterally symmetrical.

Detailed explanation-2: -It is a type of symmetry where no radial plane that passes through the centre of the organisms can divide it into two equal halves. The symmetry is neither visible for the morphological features and nor anatomically. Asymmetrical symmetry is found in snails, flounders and hermit crabs.

Detailed explanation-3: -Animal body plans follow set patterns related to symmetry. They can be asymmetrical, radial, or bilateral in form. Asymmetrical animals are those with no pattern or symmetry, such as a sponge.

Detailed explanation-4: -In contrast, there are organisms lacking external symmetry and are described as asymmetrical. Some of the animals exhibiting asymmetry are flounders and hermit crabs. Adult flounders have both eyes on one side. Hermit crabs have a large claw on one side.

Detailed explanation-5: -Figure 15.4: Animals exhibit different types of body symmetry. The (a) sponge is asymmetrical and has no planes of symmetry, the (b) sea anemone has radial symmetry with multiple planes of symmetry, and the (c) goat has bilateral symmetry with one plane of symmetry.