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

Determine the case when starches treated with heat, Determine the case when...

Determine the case when starches treated with heat In the case of starches treated with heat in presence of acid or alkali, the alteration is a minor fragmentation; similarly,

Conduits-surgery for coronary artery disease, Conduits Figure: Ve...

Conduits Figure: Venous Conduits Reversed saphenous vein was the first conduit used for CABG. 'It is usually harvested from the leg starting above the ankle going up

Define lipoprotein metabolism, Q. Define Lipoprotein Metabolism? Lipopr...

Q. Define Lipoprotein Metabolism? Lipoproteins serve to transport absorbed dietary fat and endogenously synthesized cholesterol and triglyceride. Nevertheless, it is possible t

Main factors that affect the growth of a population, Q. What are the main f...

Q. What are the main factors that affect the growth of a population? The major factors that make populations grow are births and immigration. The major factors that make popula

Define inhibitors and enhancers - absorption of dietary iron, Define Inhibi...

Define Inhibitors and Enhancers - absorption of dietary iron? Phytates and fibre from whole grain cereals, tannins and polyphenols in tea, oxalates in green leafy vegetables li

What is atom, What is atom? Atoms are the smallest component of matter ...

What is atom? Atoms are the smallest component of matter that determine its unique chemical and physical properties. They are composed of negatively charged electrons, positive

Correct regarding a buffer, Select all that are true or correct regarding a...

Select all that are true or correct regarding a buffer: alternately donating and accepting ions a set of chemicals that work together to resist pH change often a weak acid or base

Define deuterostomes in animal kingdom, Define Deuterostomes in animal king...

Define Deuterostomes in animal kingdom? Coelomate animals are thought to have separated into two divergent lines of evolution in terms of the way embryos develop. In the embryo

Fungi, what is the symmetry of fungi?

what is the symmetry of fungi?

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