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

Why the rate of photosynthesis does increases, Why the rate of photosynthes...

Why the rate of photosynthesis does increases, peak, and then reduces as temperature increases? Increasing the temperature initially accelerates the many chemical reactions in

1, #phyletic lineage ..

#phyletic lineage ..

Alkaline phosphatase, Alkaline Phosphatase is an enzyme which catalyzes th...

Alkaline Phosphatase is an enzyme which catalyzes the hydrolysis of the phosphomonoesters of the 5' nucleotides. It is used to dephosphorylate (remove phosphate groups from) the 5

What is the meaning of cardiovascular system , What is the meaning of Cardi...

What is the meaning of Cardiovascular System ? The cardiovascular system takes care of the distribution of gases, nutrients, hormones, immune elements, and the removal of waste

Explain the role of the carbon atom, Each of the properties that follow is ...

Each of the properties that follow is characteristic of the carbon atom. In each case, indicate how the property contributes to the role of the carbon atom as the most important at

Calorie requirements for ulcerative colitis, Q. Calorie requirements for ul...

Q. Calorie requirements for ulcerative colitis? Energy: The calorie requirements must be increased to: 1) Restore weight status and maintain ideal weight. 2) Compensate f

What are plasmids, What are plasmids? Plasmids are circular DNA molecul...

What are plasmids? Plasmids are circular DNA molecules there in the genetic material of some bacteria. They might be containing genes responsible for bacterial resistance to so

425, #questionThree actographs (look closely to see the labels A, B, and C)...

#questionThree actographs (look closely to see the labels A, B, and C). Assume that the abscissa is either 24 or 48 hours for each actograph. You are asked to write two sentences f

Centrioles, Centrioles Centrioles is also called cell centre . C...

Centrioles Centrioles is also called cell centre . Centrosome discovered by Benden . T. Boveri called it centrosome. Centrosome is present in all animal eukaryotic

What are the amylase inhibitors, What are the Amylase Inhibitors? Inhib...

What are the Amylase Inhibitors? Inhibitors of the enzyme a-amylase are found in wheat, rye, beans, mango, legumes, potatoes, sorghum (jowar) and oats. Most amylase inhibitors

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