Bilateral - metazoa, Biology

Assignment Help:

Bilateral - Metazoa

Bilaterally symmetrical animals have the major axis running from head (anterior) to tail (posterior). They have a ventral (lower) and dorsal (upper) surface that are different from each other. They have only two sides that look alike, the right and left. The animal can be divided into just two identical halves through a plane which passes from anterior to posterior end. Almost all animals including human beings except for sponges, ctenophores and cnidarians show bilateral symmetry.

Adult echinoderms, though radially symmetrical (pentamerous) have larvae that are bilateral. This is because they have evolved from bilaterally symmetrical ancestors. In general, bilateral animals that adopt a sessile existence commonly exhibit a shift towards radial symmetry. The shift may be slight as in acorn barnacles where only protective circular wall plates are arranged radially or the shift may be profound as in the case of sea stars or starfishes. Bilateral animals are called Bilateria.


Related Discussions:- Bilateral - metazoa

What is electrocardiogarm, Q. What is Electrocardiogarm? Poor R-wave pr...

Q. What is Electrocardiogarm? Poor R-wave progression, in precordial leads, or q-waves in anterior leads. Intraventricular conduction defects, esqecially LBBB are common. There

What do you mean by cori cycling, What do you mean by Cori Cycling? In ...

What do you mean by Cori Cycling? In this cycle, glucose released by peripheral tissues is metabolized to lactate, which is then resynthesized to glucose in the liver. This pro

Coordination of digestion, Coordination of Digestion You have learnt ...

Coordination of Digestion You have learnt that digestion is a process in which large food molecules arc broken down step by step into their constituents. In primitive metazoa

Describe components of a complete diagnosis, Describe Components of a Compl...

Describe Components of a Complete Diagnosis of Congenital Heart Disease ? A complete diagnosis of congenital heart disease requires accurate and thorough description of the he

Explain chancroid, Chancroid  Chancroid, caused by Haemophilus ducreyi,...

Chancroid  Chancroid, caused by Haemophilus ducreyi,  is rare in the US. A single dose of azithromycin or ceftriaxone is usually effective, but may be less effective in HIV-inf

Explain absorption and metabolism of minerals, Explain Absorption and Metab...

Explain Absorption and Metabolism of Minerals? All minerals in the diet are not equally absorbed. Also different compounds and complexes of same mineral are absorbed with diffe

What is threshold value when the system is in steady state, In a properly f...

In a properly functioning negative feedback system, the A. value of the controlled variable will always be very close to the threshold value when the system is in steady state.

Name the foods allowed in soft diet, Which Foods allowed in soft diet:- ...

Which Foods allowed in soft diet:- Soups - mildly flavoured -  broths and cream soups. Beverages -  all Meat -  moist, tender meat, fish or chicken, cottage cheese, eggs

Antiparkinsonian drugs, Antiparkinsmian Drugs: Antiparkinsonian drugs ...

Antiparkinsmian Drugs: Antiparkinsonian drugs are  the  specific drugs  to treat the extrapynnidal side effects  of  antipsychotic agents.  Anticholinergic drugs  block

Define vitamins b12 deficiency in vegans, Define Vitamins B 12 Deficiency ...

Define Vitamins B 12 Deficiency in Vegans? Because plants do not synthesize vitamin B 12 , individuals who consume diets completely free of animal products (vegan diets) are a

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