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

Measuring biodiversity, Diversity is defined as the no of species present i...

Diversity is defined as the no of species present in a community termed as "species richness". We can represent species biodiversity at different geographical scales as alpha, beta

What do you mean by crystalline style, What do you mean by crystalline styl...

What do you mean by crystalline style? A rodlike structure in some mollusc stomachs which is made of enzymatic proteins required for digestion. Cilia lining the stomach rotate

Identical karyotypes and identical genomes, Q. Can two normal individuals o...

Q. Can two normal individuals of the same species with sexual reproduction have identical karyotypes and identical genomes? And how is the human karyotype usually represented?

Amphibia, an assignment of amphibians

an assignment of amphibians

How dissimilar are walls of these two types of blood vessel, Are the arteri...

Are the arteries or the veins constituted of more muscle tissue? How dissimilar are the walls of these two types of blood vessels? The arterial system has thicker muscle walls

Explain about vitamin E, Vitamin E (DL-α-Tocopherol) DL-α-Tocopherol is...

Vitamin E (DL-α-Tocopherol) DL-α-Tocopherol is a yellow to red-brown,  clear, viscous oil almost without odour which decolourise when exposed to light and air. DL-α-Tocopherol

Define amino acids in the building blocks of proteins, Define Amino Acids i...

Define Amino Acids in the Building Blocks of Proteins? Amino acids, as you have already illustrated, have a carboxyl group and an amino group bonded to a common carbon atom and

Explain gene expression - nutrient gene interactions, Explain Gene Expressi...

Explain Gene Expression - Nutrient Gene Interactions? The last two decades have witnessed tremendous development in our understanding of the cellular processes at the molecular

Find out risk factors for coronary disease, Q. Find out risk factors for co...

Q. Find out risk factors for coronary disease? 1) Tobacco Smoking, the single most preventable cause of death is a leading risk factor for CAD, cerebrovascular accident and

Phylum platyhelmenthiese, show heading wise characteristics of phylum platy...

show heading wise characteristics of phylum platyhelmenthiese

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