Question

Question 3 (0.25 points) Why is symmetry important? O It helps the animal move. It helps organize groups of animals. O It helps the animal eat. It helps animals recognize one another.

Answer 1

Symmetry, in biology, the repetition of the parts in an animal or plant in an orderly fashion. Specifically, symmetry refers to a correspondence of body parts, in size, shape, and relative position, on opposite sides of a dividing line or distributed around a central point or axis.

Animals can be classified by three types of body plan symmetry: radial symmetry, bilateral symmetry, and asymmetry.

Animals with radial symmetry have no right or left sides, only a top or bottom; these species are usually marine organisms like jellyfish and corals.

Most animals are bilaterally symmetrical with a line of symmetry dividing their body into left and right sides along with a “head” and “tail” in addition to a top and bottom.

Only sponges (phylum Porifera) have asymmetrical body plans.

Some animals start life with one type of body symmetry, but develop a different type as adults; for example, sea stars are classified as bilaterally symmetrical even though their adult forms are radially symmetrical.

IMPORTANCE OF SYMMETRY:

It helps the animal move: In addition to having a more developed nervous system, bilaterally symmetrical animals can move more quickly than animals with other body plans. This bilaterally symmetrical body plan may have evolved to help animals better find food or escape predators.

It helps organize group of animals: At a very basic level of classification, true animals can be largely divided into three groups based on the type of symmetry of their body plan: radially symmetrical, bilaterally symmetrical, and asymmetrical. Only a few animal groups display radial symmetry, while asymmetry is a unique feature of phyla Porifera (sponges). All types of symmetry are well suited to meet the unique demands of a particular animal’s lifestyle.

It helps animal find food :Animals with radial symmetry all live in water. Most of them can't move very quickly. They rely on water currents to bring food to them. One advantage of having radial symmetry is that the animal can get food from any direction. Larger, more complex animals all have bilateral symmetry. They have very different front and back ends. Different parts of the body are specialized to do different jobs. Sense organs around the front end or head help bilaterally symmetrical animals find food. Hence symmetry helps animals find food but not to eat it .Bilateral symmetry also helps animals avoid enemies.

Symmetry in recognizing one another :Bilateral symmetry body plan helps animals escape predators and avoid enemies but does not help them in recognizing one another.

Hence answers are Aand B.