Types specimens of echpnodermata, Biology

Assignment Help:

Types specimens of echpnodermata

Before we begin the study of the selected specimens of the following echinoderms - Feather star, Brittle star, Sea urchin, Sea cucumber and Star fish. You should be aware that though members of the various classes of ecchinoderms often appear to be superficially different, however their structure is fundamentally similar. For example sea cucumbers tack the five arms of sea stars, but they do have five bands of tube feet and thus show the same basic pentaradiate symmetry.

Antedon is commonly called "feather star" or "sea lily" Examine the specimen and note the following features:

(i)The body of Antendon is made of a central convex disc of calyx and five equidistant, elongated slender radiating arms.

(ii)Each arm is divided into two branches at the base, so there are in effect ten long arms.

(iii)The arms are slender, flexible, movable and bear small spine-like structures or pinnules on the two sides.

(iv)The body has a distinct upper oral and lower aboral surface.

(v)Aboral surface bears several root-like, slender, curved, jointed cirri supported by small ossicles which help to attach Antedon to rocks.

(vi)Oral surface is covered with a soft and leathery skin, called tegmen and this surface bears the mouth and anus on the same side of the calyx. The anus is borne on a tiny papilla and is excentric whereas the mouth is in the center.
 
(vii)Five ambulacral ciliated grooves radiate from the mouth towards the arms. Each groove divides into two and runs along the oral surface of each arm.

(viii)The intervening body surface is the adambulacra.

(ix)Tube feet or podia are without suckers and can be seen along the edges of ambulacral groove.

(x)The exoskeleton is made of calcareous ossicles or plates.


Related Discussions:- Types specimens of echpnodermata

Elaborates the pathophysiology of ventricular septal defect, Elaborates the...

Elaborates the Pathophysiology of ventricular septal defect? The shunt in the VSD is left to right. The magnitude of the shunt is determined by the size of the VSD and the, lev

How can we control the disease cholera, How can we control the disease Chol...

How can we control the disease Cholera Control: Individuals infected  with cholera require oral rehydration therapy  with NaCl plus sucrose, sodium bicarbonate and potassium ch

Puerperal psychosis and rape - psychiatric emergencies, Puerperal Psychosis...

Puerperal Psychosis: Child birth can precipitate schizophrenia, depression and mania. Management:  it  depends on  the nature of the symptoms. Danger  to  self and othcrs (inc

Calculate rate of heat removal per hour, Strawberries are quick frozen at a...

Strawberries are quick frozen at a rate of 6500 kg/h. The fruit enters the freezer at a temperature of 15°C and is frozen to a final temperature of -20°C. Calculate the rate of hea

Secondary succession - community change, Secondary Succession - Community C...

Secondary Succession - Community Change Secondary succession is the sequential development of biotic communities after the complete or partial destruction of the existing comm

Manx cats are heterozygous for a dominant mutation, Manx cats are heterozyg...

Manx cats are heterozygous for a dominant mutation that results in no tails or very short tails, large hind legs and a distinctive gait. The mating of two Manx cats yields two Manx

Explain about the pulmonary and respiratory system, Explain about the Pulmo...

Explain about the Pulmonary and Respiratory System? With aging the chest wall becomes stiffer and less compliant and the muscular force of the diaphragm is reduced causing less

What percentage of the offspring would be tall, Tall (T) plants are dominan...

Tall (T) plants are dominant and short (t) plants are recessive. Two heterozygous tall plants are crossed. What percentage of the offspring will be tall?

Codon bias, Codon Bias  is the tendency for an organism or virus to make us...

Codon Bias  is the tendency for an organism or virus to make use of certain codons more than the others to encode a particular amino acid. A significant detrminant of codon bias is

Fats requirements during congestive cardiac failure, Q. Fats requirements d...

Q. Fats requirements during congestive cardiac failure? Fat: The quantity and quality of fat would be governed by the severity of hyper- lipidemia and adiposity. Emphasis, as

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd