Journal of Marine Science: Research & Development
Open Access

The sponges, worms, and other invertebrate animals are occurring in aquatic habitats in throughout the world, but many of these organisms have not been well studied taxonomically, let alone in terms of their ecological characteristics and relationships. Due to because the fish can be operated readily and the potential for living species to increase their effectiveness as natural enemies is higher than that with terrestrial organisms where widespread natural dispersion may have already covered most possibilities. The earliest animals were coming under the marine invertebrates i.e., vertebrates came later for the feed. Animals are multicellular eukaryotic type, and they are differentiated from plants, algae, and fungi by lacking cell walls. The sea invertebrates are living in the underwater that inhabit a marine environment apart from the vertebrate members; invertebrates lack a vertebral column. Some have evolved a shell or a rough encasement.

Some invertebrate phyla have only one species, while others like Arthropoda include more than 83% of all described animal species with over a million species. The most common marine invertebrates are sponges, cnidarians, marine worms, lophophorate, mollusks, arthropods, echinoderms, and the hemichordates. The anatomy of a typical sponge is organized so that flagella inside the sponge pull water into small holes (ostia) in the body and expel waste through larger holes called as oscula. Sponge species have a variation of body plans that contribute the structure, which means that the specimen appears to be the longest-lived animal on earth yet recorded. Sponges are often considered by scientists to find indications about the first life forms on globe with additional than one cell.

Sponges are hermaphroditic and can reproduce both sexually and asexually. Most sponge types are usually reproducing by sexual reproduction, where the sperm cells are introduced to (spermatocytes) develop from choanocytes (collar cells) and eggs develop from oocytes. When environmental conditions are favorable, spermatocytes are ejected in out-going currents and the eggs, once fertilized inside the sponge in some sponges, develop into flagellated larva that swim. Asexual reproduction occurs when favorable environmental conditions deteriorate and includes both regeneration (regenerating from fragments), budding (groups of cells differentiate into small sponges that are then released externally or expelled through the central canal (oscula)), or the formation of gemmules.