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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Explain adaptive radiations in Polychaeta

Modes of life of Polychaetes Posted on: Login to post your comment here Eyes, tentacles and palps are also usually absent. In Chaetopterus the parapodial setae become peg-like or hook-like for anchoring the animal to the wall of the tube and water current is maintained by three fan-like appendages.

Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes”. The Hawaiian lobelioids are significantly more speciose than the silverswords, perhaps because they have been present in Hawaii for so much longer: Sabella or the peacock worm lives in vertical parchment tube and projects the fan-like tentacles which are covered with sticky mucous to which the minute food particles get attached and are carried to mouth through the ciliated groove.

Four features can be used to identify an adaptive radiation: They feed on small invertebrates including other polychaetes.

Ophellids, Maldanids Indirect deposit feeders- These animals lack proboscis instead they are provided with highly extensile ciliated grooved tentacles, secreting mucous. Terebella, Pectinaria Filter feeders: In these animals water current carries micro-organisms inside the burrow and then tentacles move the food towards the mouth.

A Story of Evolution in Our Time. And accordingly they show great adaptive diversity. Calcareous tubes- These tubes are made up of polychaeeta.

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Lake Victoria’s cichlids are also a species flock, once composed of some or more species. 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.

Nereis, Phyllodoce, Colycera Pelagic polychaetes: In Aphrodite the body is short and broad with arched dorsal side and a flat ventral side to permit creeping under the stones and crevices. These are marine, freely moving animals that crawl on sea bottom.

Arenicola excavates L-shaped burrows. With over species currently recognized, often placed in a single genus Anolisthey constitute one of the largest radiation events among all lizards. Histriobdella lives as ectoparasite in the gill chamber of crustaceans and sucks blood.

Proceedings of the Royal Society B. The Hawaiian honeycreepers form a large, highly morphologically diverse species group that began radiating in the early days of the Hawaiian archipelago. By using this site, you agree to the Terms of Use and Privacy Policy.

Explain adaptive radiations in Polychaeta –

The cichlids of Lake Malawi constitute a “species flock” of up to endemic species. The National Academies Press. 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.

Their setae have become hook-like to anchor in the burrow. Direct deposit feeders include burrowing and tube-dwelling species. Crawling polychaetes belong to order Errantia which includes marine, freely moving animals that crawl on sea bottom.

The raptorial feeding is performed by eversible pharynx which is provided with chitinous jaws and dentacles on the internal lining. Their head is provided with long bipinnate filaments called radides with a ciliated groove adaptie along the oral surface. Darwin’s finches are an often-used textbook example of adaptive radiation.

Proceedings of the National Academy of Sciences. Mouth has eversible pharynx.

In these animals, for burrowing mode of life the external surface of body has become smooth and parapodia have become small to give minimum friction during burrowing.

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Body segments are generally similar.

Adaptive radiation – Wikipedia

Cirri are generally longer as they carry tangoreceptors and help in locating food. Many polychaetes, such as Nereis crawl on the seabed in night in search of food and burrow in the soil in day time. Locomotory organs or parapodia are large, they bear setae which can be retracted and protruded out in various directions for crawling among rocks and stones. From Wikipedia, the free encyclopedia. Radides are used in food collection.

Presented above polychata the most well-documented examples of modern adaptive radiation, but other examples are known. These Madagascan examples are significantly older than most of the other examples presented here: Sometimes these tubes may be covered by sand grains and shells Ex: Victoria is famously home to a large number of piscivorous cichlid species, some of which feed by sucking the contents out of mouthbrooding females’ mouths.

The sedentary polychaete species rely on this food source. Sense organs on prostomium and peristomium are well developed due to the free swimming and crawling habit.

Shell and sand grain tubes- These kinds of tubes are usually straight, avaptive vertically in sand or mud. Setae help to anchor against the burrow wall.

Its anterior part of body and tentacles can be projected out to collect planktonic food particles polycyaeta which it feeds. Admin Introduction Polychaeta is the largest class of phylum Annelida. These animals spend most of their time inside the burrows and come out only to catch the prey.

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