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

Which chemical causes tooth destruction, The bacteria that cause dental cav...

The bacteria that cause dental cavities in humans break down sugars, releasing what chemical which causes tooth destruction? a) Acids b) Bases c) Enzymes d) Monosaccha

List a few important uses of food hydrocolloids, List a few important uses ...

List a few important uses of food hydrocolloids. A few important uses of food hydrocolloids are: to increase viscosity and to stabilize food products. Its other uses  include u

Explain the most probable number (mpn), Explain the Most Probable Number (M...

Explain the Most Probable Number (MPN)? MPN is a statistical estimating technique which is based on the fact that more the number of bacteria in a sample, more is the dilution

What are the three main limiting factors of photosynthesis, What are the th...

What are the three main limiting factors of photosynthesis? The three major limiting factors of photosynthesis process are light intensity, carbon dioxide concentration and tem

What is the characteristic of cardiac muscle, What are the characteristics ...

What are the characteristics of cardiac muscle that allow it to be highly resistant to fatifue?

How many types of gametes can be formed, How many different types of gamete...

How many different types of gametes can be formed by individuals of the following genotypes? What are they in each case a) AaBb b) AaBB c) AaBbCc d) AaBBCc e) AaBbcc f) AaBbCcDdEe

Determine the enzymatic chemical reactions, How does facilitated diffusion ...

How does facilitated diffusion present similarities with enzymatic chemical reactions? One of the main examples of facilitated transport is the entrance of glucose from the blo

Write down a dna palindrome, Write a DNA palindrome or inverted repeat of a...

Write a DNA palindrome or inverted repeat of at least 10 nucleotides in length.

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