Mutations and rearrangements that occur by misalignment during DNA replication are frequent sources of genetic variation in bacteria. Dislocations between a replicating strand and its template at repetitive DNA sequences underlie the mechanism of these genetic events.
Cnidarians take on two basic forms, a medusa and a polyp. The medusa form is a free-swimming structure which consists of an umbrella-shaped body (called a bell), a fringe of tentacles that hang from the edge of the bell, a mouth opening located on the underside of the bell, and a gastrovascular cavity. The mesoglea layer of the medusa body wall is thick and jelly-like.
There are two types (or body plans) of cnidarians. There is the Medusa, which is a Jellyfish, really. And there is a Polyp, which is like an upside-down Jellyfish, if you want it simply.A polyp would be your sea anemone or coral.They spend most of their lives attached to a hard surface underwater. All Cnidarians are aquatic and carnivorous, and they occur in two basic body shapes: polyps,â¦. 2  Characteristics of Cnidaria Cnidaria is an alternative name for the invertebrate phylum Coelenterata, giving emphasis to the stinging structures as characteristic of the phylum.