Locomotion in Mollusca
Locomotion type mostly correlates to the feeding habit. e.g. Herbivorous mollusc are slower than carnivorous molluscs. Terrestrial Snails: Foot developed to a flat sole on the ventral side. Wave like…
Feeding mechanisms in Mollusca
May be herbivores, carnivores, filter feeders or detritivores.They have a coelom, a complete digestive system and specialised organs for excretion.Bivalve molluscs can filter-feed fine particles from the water.Single-shelled molluscs (limpets)…
Social organization in insects
Social InsectsLive together in organised groups or colonies.Each individual contributes towards welfare of the entire group.Large populations — complex social aggregate called a colony.All members in a colony are offspring…
Metamorphosis in insects
Ametabolous(No metamorphosis) Newly hatched creature looks exactly like an adult except for size and development of spine and setae.e.g. Silverfish and Spring Tails. Hemimetabolous(Incomplete metamorphosis) Immature stages are the nymphs…
Types of mouthparts in insects
Insects feed on animals and plants in a variety of ways and their mouthparts have become modified for these purposes.Mouth parts are essentially the paired appendages of mandibles and maxillary…
Parasitism in crustacea
Parasitism prevails in several groups of Crustacea — Copepoda, Branchiura, Cirripedia, Isopoda and Amphipoda. Copepoda (Fish Lice): Majority of crustacean parasites. Exhibit diverse array of morphological modifications, from free living…
Crustacean larval forms
Crustacea has both direct and indirect development. Naupliuse.g. Cyclops Characteristic of class Nauplius.Simplest and commonest, found in marine crustaceans and malacostracans.When development proceeds through many larval forms, Nauplius is the…
Polychaetes
Adaptive Radiation: Evolution and spread from a single ancestral species to a variety of forms occupyingdifferent niches. Habit and Habitat: Crawling Live under stones, submerged vegetation.Well developed head bearing several…
Metamerism
Segmentation in bilateral animals (like Annelida) which involves a longitudinal division of body into a linear series of similar sections or parts.Each segment is called a somite or metamere.Metamerism is…
Annelida: General features
Mostly aquatic, some terrestrial. Burrowing and tubicolous, Some are commensal and parasitic.Body elongated and bilaterally symmetrical. Triploblastic. True coelom.Metamerically segmented into similar metameres.Epidermis made from a single layer of columnar…