ADAPTIVE RADIATION IN POLYCHAETA PDF

ideal for examining adaptive radiations in extreme environments. Did dorvilleid northern California and Oregon, dorvilleid polychaetes. Polychaeta is the largest class of phylum Annelida. The following is the discussion of the adaptive diversity of polychaetes, swim near the surface of the sea where the danger of predators and solar radiation is excessive. Phylogeny and Adaptive Radiation, Segmented Worms in The Diversity of On the other hand, polychaetes with well-developed parapodia are generally.

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The Hawaiian honeycreepers form a large, highly morphologically diverse species group polychatea began radiating in the early days of the Hawaiian archipelago. Annual Review of Ecology, Evolution, and Systematics.

These are marine, freely moving animals that crawl on sea bottom.

Adaptive radiation

Explicit use of et al. The tubes of various species vary greatly polychaeat form and construction. It periodically ingests sand with the help of its simple proboscis.

In other projects Wikimedia Commons. In these animals water current carries micro-organisms inside the burrow and then tentacles move the food towards the mouth. History un evolutionary theory. Its small body is oval in shape and parapodia are modified for clinging onto the host. Body segments are generally similar Ex: Terebella, Pectinaria Filter feeders: This mucus bag ends in a ciliated food cup where the food is rolled up into a ball and passed forward to the mouth along the ciliary groove.

Their setae have adaptiive hook-like to anchor in the burrow. Its parapodia are modified for clinging and mouth parts transform into piercing stylets for sucking blood.

However, in Amphitrite and Terebella there are long feeding tentacles on the anterior end and bunches of gills for respiration.

Admin Introduction Polychaeta is the largest class of phylum Annelida. For example, all members of the Malawi species flock are mouth-brooders, meaning the female keeps her eggs in her mouth until they hatch; in almost all species, the eggs are also fertilized in the female’s mouth, and in radiwtion few species, the females continue to guard their fry in their mouth after they hatch.

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Adaptive radiation is not a strictly vertebrate kn, and examples are also known from among plants. The haplochromine cichlid fishes in the Great Lakes of the East African Rift particularly in Lake TanganyikaLake Malawiand Lake Victoria form the most speciose modern example of adaptive radiation.

Sense organs on prostomium and peristomium are well developed due to the free swimming and crawling habit. Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes”. Body segments are generally similar.

Their body is elongated, prostomium is reduced or absent.

Cirri are generally longer and carry tango receptors which help in locating food. Some have large eyes while others have none. These kinds of polychaetes are adapted to live in open sea and are semi-transparent in appearance.

These worms are carnivorous and extend out from the tube openings to catch the prey. Direct deposit feeders- Some of the polychaetes obtain their food by directly swallowing sand and mud as they burrow through it.

Modes of life of Polychaetes Posted on: Social implications Evolution as fact and theory Social effects Creation—evolution controversy Objections to evolution Level of support. The following is the discussion of the adaptive diversity of polychaetes. In these animals, for polycheta mode of life the external surface of body has become smooth and parapodia have become small to give minimum friction during burrowing.

Explain adaptive radiations in Polychaeta

They move through the substratum by their peristaltic contraction movements. They are also known as planktonic polychaetes. Arenicola excavates L-shaped burrows. The food particles in this water current are filtered out into the mucous bag formed by ciliated glandular epithelium. Head bears sense organs such as eyes, tentacles and palps. Parapodia are lost or reduced or modified for anchoring in the tube.

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Login to post your comment here These tubes are composed of sand grains and shell pieces cemented together with mucus. Parapodia help in crawling and swimming. Polychaeta is the largest class of phylum Annelida. On Madagascar, birds of the family Vangidae are marked adapitve very distinct beak shapes to suit their ecological roles. Their head is provided with long bipinnate filaments called radides with a ciliated groove running along the oral surface. Mouth has eversible pharynx.

Polychaete diversity | Zoology for IAS, IFoS and other competitive exams

Vanadis, Tomopteris Burrowing polychaetes: The cichlids of Lake Malawi constitute a “species flock” of up to endemic species. Nereis, Phyllodoce, Colycera Pelagic polychaetes: Radides are used in food collection. Effective poylchaeta compartment the coelomic fluid which has skeletal role in locomotion.

These tubes may measure about 70 cm long and 2. Tubicolous annelids are capable of secreting mucous or other adhesive substance to which sand and shell particles get attached and make the tube strong, e. Lake Tanganyika itself is believed to have formed million years ago, putting a recent cap on the age of the lake’s cichlid fauna. These food particles reach the mouth by wiping the tentacles across the lips.

For the ground finches, this niche is a diet of seeds, and they have thick bills to facilitate the consumption of these hard materials.