Question

Answer all three

1. Identify two traits shared by members of the phyla Echinodermata and Chordata not seen in the other animal phyla you observed.

2. Hypothesize why the skeletons of vertebrates have the same general bone types.

3. What is an advantage of bilateral body symmetry?

Answer 1

1. Two traits shared by members of the phyla Echinodermata and Chordata are:

Share similar embryonic development (anus first), formation of the mouth at the end of the embryo opposite the blastopore, radial cleavage (cells divide perpendicularly to line)

2. Fish, frogs, reptiles, birds and mammals are called vertebrates, a name that comes from the bony column of vertebrae (the spine) that supports the body and head. The rest of the skeleton of all these animals (except the fish) also has the same basic design with a skull that houses and protects the brain and sense organs and ribs that protect the heart and lungs and, in mammals, make breathing possible.

Each of the four limbs is made to the same basic pattern. It is joined to the spine by means of a flat, broad bone called a girdle and consists of one long upper bone, two long lower bones, several smaller bones in the wrist or ankle and five digits.

These features can be attributed to the presence of same general bone types in vertebrates.

3. Bilateral symmetry allows for a more streamlined body shape and offers more advantages for animals with active lifestyles than radial symmetry. The streamlined body creates less drag when moving through the watery environment, and thus less energy is required for movement.