Lancelet- its importance in evolution PHYLOGENESIS OF CHORD AVIAN EXCREATORY

DEVELOPMENTAL DISORDERS OF THE
EXCREATORY SYSTEM
IN HUMANS
Course Students
AISHWARYA

& SAYANDIP DAS
Scientific Leader
Svetlana Smirnova

"fish-like" benthic filter feeding chordates [n the order Amphioxiformes. They are the modern

representatives of the subphylum Cephalochordata.

around the world.
The only exception is Asymmetron inferum, a species known

from the vicinity of whale falls at a depth of about 225 m (738 ft).
Although they are able to swim, adult amphioxi are mostly benthic. They live in sandy bottoms whose granulometry depends on the species and the site, and they are usually found half-buried in sand.

the front end to the water and filter-feed on plankton

by means of a branchial ciliary current that passes water through a mucous sheet. Branchiostoma floridae is capable of trapping particles from microbial to small phytoplankton size,while B. lanceolatum preferentially traps bigger particles (>4 µm).

via external fertilization. They only reproduce during their spawning season, which varies slightly

between species - usually corresponding to spring and summer months.
All lancelets species spawn shortly after sunset, either synchronously (e.g. Branchiostoma floridae, about once every 2 weeks during spawning season) or asynchronously (Branchiostoma lanceolatum, gradual spawning through the season.

key animal in understanding the origin of vertebrates. However, the

evolutionary history within this lineage remains unexplored. As the amphioxus lineage has likely been separated from other chordates for a very long time and displays a marked left-right asymmetry, Its evolutionary history is potentially helpful in better understanding chordate and vertebrate origins. We studied the phylogenetic relationships within the extant amphioxus lineage based on mitochondrial genomes incorporating new Asymmetron and Epigonichthys populations, and bosed on previously reported nucléar transcriptomes.

the dogfish shark, clearly show that the excretory system arises

from a series of tubules, one pair in every segment of the body between the heart and the tail. This continuous series of tubules constitutes the archinephros, the name implying that the kidney of the ancestral vertebrate had some such form as this. Each tubule opens internally to the body cavity and may, in the remote past, have opened separately to the exterior; but in all living vertebrates the tubules open on each side into a longitudinal duct, the archinephric duct

two archinephric ducts unite before opening to the exterior. Later

in development, Bowman’s capsule arises as a diverticulum of each tubule, subsequently becoming indented by the glomerulus. Eventually, the tubules usually lose their internal openings to the body cavity. The most anterior tubules of the archinephros (pronephros) usually degenerate in the adult.
In the reptiles, birds, and mammals there is greater separation of function, the mesonephros being exclusively genital and the metanephros being exclusively urinary.

DISEASE

ALPORT SYNDROME

FABRY DISEASE