Question

write morphology and life cycle obelia​

Answer 1

Answer:

1)Morphology

The hydroid colony of Obelia is delicate, semitransparent and whitish to light brown in color

2) Life Cycle

the Obelia life cycle begins as immobile polyp colonies that contain digestive hydrant and reproductive gonangium units. The gonangium reproduce asexually, releasing medusa by budding. The medusa, or jellyfish, swim freely and reproduce sexually, releasing eggs and sperm into the water

Answer 2

Answer: External morphology

Obelia is also called as Sea fur. The hydroid colony of Obelia is delicate, semitransparent and whitish to light brown in color. It consists of vertical branching stems are called as hydrocauli and the root like branches are called hydrorhiza. Both are of same thickness. The growth of the colony is sympodial.

Explanation: life cycle:

The primary function of the medusa is sexual reproduction. Obelia is dioecious as each medusa has reproductive organs of only one sex. There is no difference between the male and female medusae. The gonads (testis or ovaries) are four in number and lie on the sub-umbrella, below the radial canals, in the form of knobs. Thus gonads are per-radial in position. They are situated almost at equal distances between the manubrium and the velum. The gonads which arise as diverticula of the radial canals have the same structure as the body wall of medusa. The sex cells start developing very early when the medusa is being formed. These cells originate in the ectoderm of the manubrium, migrate to the endoderm and finally make their way to the gonads. They lie between the ectoderm of the sub-umbrella and the mesogloea.