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

Can you explain ventricular septal defect, Q. Can you explain Ventricular S...

Q. Can you explain Ventricular Septal Defect? VSD can be found in various part of ventricular septum hence all possible views except suprasternal views are used to detect an

Protozoa, Locomotion,nutrition and reproduction in ptotozoa

Locomotion,nutrition and reproduction in ptotozoa

0smosis, what is the difination of osmosis

what is the difination of osmosis

Name the term when maximum arterial pressure is attained, At the end of the...

At the end of the ventricular contraction, maximum arterial pressure is attained and blood flow is most rapid. This is correctly termed the: a) Arterial maximum b) Diastolic

What is phytates, Q. What is Phytates? Phytates are widely distributed...

Q. What is Phytates? Phytates are widely distributed in seeds of vegetables, fruits and grains. Unrefined cereals and millets are the richest sources of phytates. Refined or

What is transportation of sick newborn infants-heart disease, What is Trans...

What is Transportation of Sick Newborn Infants with Heart Disease Communication : The decision to transport a newborn to a tertiay referral centre with facilities for specia

Explain the Process of dna technology - Enzymes, Explain the Process of dna...

Explain the Process of dna technology Procedures involving recombinant DNA technology has been used to increase the yield of enzymes already produced by the microorganisms, e.

What are the types of colloidal dispersions, What are the types of colloida...

What are the types of colloidal dispersions Depending upon the relative affinity of the dispersed phase for the dispersion medium, colloidal dispersions are, further divided in

Echocardiography, Both global and regional systolic function are to be chec...

Both global and regional systolic function are to be checked. Global measures include ejection fraction, stroke volume, end systolic volume. (For measurement of systolic function u

Reproduction, briefly deccribe the eggs snd follicles

briefly deccribe the eggs snd follicles

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