FURTHER PHYLOGENETIC CONSIDERATIONS 1. Traditional interpretation It suggests that the ancestral polychaetes gave rise to modern polychaetes through adaptive radiation. Then a group of annelids adapted in freshwater. The fresh…
CLASS HIRUDINEA (hirdin, leech') The class Hirudinea contains five hundred species of leeches. Most leeches are fresh water. Some are marine. Some are completely terrestrial. Leeches prey on small invertebrates…
CLASS OLIGOCHAETA (oligos, few + chaete, hair) The class Oligochaeta has over three thousand species. They are found throughout the world in freshwater and terrestrial habitats. A few oligochaetes are…
CLASS POLYCHAETA (Poly, many + chaise, hair) Polychaeta is the largest of the annelid classes. Polychaetes are mostly marine. They are 5 to 10 en- long. They have more than…
Phylum Annelida 1. Their body is metameric, bilaterally symmetrical, and wormlike. 2. They show protostome characteristics include spiral cleavage, trochophore larvae and schizocoelous coelom formation. 3. They have paired epidermal…
ANNELIDS METAMERIC BODY FORM EVOLUTIONARY PERSPECTIVE Population explosion of annelids: Millions of Samoan pablo worm (Eunice viridis) are produced in an island of South Pacific. The Samoan pablo worm is…
OBJECTIVES Multiple Choice Questions MCQs 1. Which of the followings is not protostome? (a) Annelids (h) Molluscs (c) Arthropods (d) Echinoderms 2. Larva develop in molluscs is: (a) Fornaria (h)…
SUBJECTIVE QUESTIONS Give evolutionary perspective of Molluscs. Give different hypothesis about the evolution of coelom. Give general characteristics of molluscs. Write note on shell of molluscs. Write note on radula.…
DEFINITIONS AND KEY POINTS FOR OBJECTIVES TERMS DEFINITIONS Coelom A coelom is a body cavity that arises in mesoderm and is lined by a sheet of mesoderm…
FURTHER PHYLOGENETIC CONSIDERATIONS Molluscs are over 500 million years old according to fossil record. There are different views about the evolution of molluscs. Protosotme ancestry The molluscs have protosotme ancestry.…
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