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.
Body segments are generally similar Ex: Body segments are generally similar. 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. Hawaii is also the site of a separate major floral adaptive radiation event: Cirri are generally longer as they carry tangoreceptors and help in locating food.
Majority of the species of polychaetes are marine and exhibit a variety of habits and habitats.
Ichthyotomus is an ectoparasite on the fins of marine eels. Direct deposit feeders include burrowing and tube-dwelling species. 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. These Madagascan examples are significantly older than most of the other examples presented here: Parapodia are lost or reduced or modified for anchoring in the tube.
However, a number of particularly divergent species are known from Malawi, including the piscivorous Nimbochromis livingtoniiwhich lies on its side in the substrate until small cichlids, perhaps drawn to its broken white patterning, come to inspect the predator – at which point they are swiftly eaten.
Sometimes these tubes may be covered by sand grains and shells Ex: The giant or emperor cichlid Boulengerochromis microlepis is a piscivore often ranked the largest of all cichlids though it competes for this title with South America’s Cichla temensisthe speckled peacock bass.
Login to post your comment here We have loaded Previous years questions with explanations University of California Press. These kinds of polychaetes are adapted to live in open sea and are semi-transparent in appearance. The other finches in the Galapagos are similarly uniquely adapted for their particular niche. Parchment tubes- These kinds of tubes are membranous, usually U-shaped.
Eyes, tentacles and palps are also usually absent. Tubicolous polychaetes live permanently inside the tubes made of mud, shell or sand grains, parchment or calcium carbonate.
The Hawaiian honeycreepers are known for their beaks, which are specialized to satisfy a wide range of dietary needs: 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. They feed on small invertebrates including other polychaetes. A cone of mucous is secreted on the anterior side for trapping food particles. Majority of the species of polychaetes are marine and exhibit a variety of habits and habitats for which they show anatomical and physiological adaptations.
Drama in Lake Victoria. They generally have semitransparent body that imparts them near invisibility. Nereis, Nephthys Detritus feeders: On Madagascar, birds of the family Vangidae are marked by very distinct beak shapes to suit their ecological roles.
The haplochromine cichlid fishes in the Great Lakes of the East African Rift particularly polyxhaeta Lake TanganyikaLake Malawiand Lake Victoria form the most speciose modern example of adaptive radiation. Lake Victoria’s cichlids are also a species flock, once composed of some or more species. Setae help to anchor against the burrow wall.
They move through the substratum by their peristaltic contraction movements. Introduction to adaptivw Evidence of evolution Common descent Evidence of common descent.
The two large glands under the collar fold secrete calcium carbonate which forms the tube. Crawling polychaetes belong to order Errantia which includes marine, freely moving animals that crawl on sea bottom.
Small food particles moving down the groove by ciliary action accumulate at the base of tentacles. Feeding is done by the peristomial funnel, mouth, ciliated groove and three fans on segments Head bears sense organs such as eyes, tentacles, antennae, cirri and palps.
Polychata Physical Anthropology 2 ed.
Madagascar’s fauna has been evolving in isolation since the island split from India some 88 million years ago, and the Mantellidae originated around 50 mya. This organically rich sand is then ingested by the worm. Arenicola, Glycera, Amphitrite and Terebella Tubicolous polychaetes: Planktonic polychaetes swim near the surface of the sea where the danger of predators and solar radiation is excessive.
Circular muscles of these animals are well developed to assist in locomotion. Polychaeya raptorial feeding is performed by eversible pharynx which is provided with chitinous jaws and dentacles on the internal lining. These food particles reach the mouth by wiping the tentacles across the lips. Pectinaria, Owenia, Diopatra, Clymenella, Sabella. Articles with short description Commons category link is on Wikidata.
Polychaete diversity | Zoology for IAS, IFoS and other competitive exams
Direct deposit feeders- Some of the polychaetes obtain their food by directly swallowing sand and mud as they burrow through it. They are also known as planktonic polychaetes. Myzostoma is a commensal that lives in the tubes of other polychaetes or with sea cucumbers and sea stars.