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

Control of the cell cycle, The cell cycle is controlled by a cyclically ope...

The cell cycle is controlled by a cyclically operating set of reaction sequences that both trigger and coordinate key events in the cell cycle • The cell-cycle control system is

What is lamarckism, What is lamarckism? The Lamarckism is the theory th...

What is lamarckism? The Lamarckism is the theory that unites the law of use and disuse with the law of the transmission of acquired characteristics that is that asserted that a

Bladder worm, what is the function of the bladder in the bladder worm

what is the function of the bladder in the bladder worm

Find the magnitude of the acceleration, A proton accelerates from rest in a...

A proton accelerates from rest in a uniform electric field of 650 N/C. At some later time, its speed is 1.3 106 m/s. Find the magnitude of the acceleration of the proton. M/s2

Define criteria for assessment of vitamin d status, Define Criteria for Ass...

Define Criteria for Assessment of Vitamin D Status? You may recall the events involved in calcium homeostasis described earlier in this section. We studied that sufficient 25-O

Etiological factor of malabsorption syndrome, Q. Etiological factor of mala...

Q. Etiological factor of malabsorption syndrome? The causes cited for malabsorption can be associated with a number of diseases. Many of these diseases you may not know presen

Kjlkjkp, Ask quesouou9ution #Minimum 100 words accepted#

Ask quesouou9ution #Minimum 100 words accepted#

What is ridge morphology, What is Ridge morphology The implant-supporte...

What is Ridge morphology The implant-supported prosthesis is affected by the ridge morphology especially implant-supported overdentures which gain dual support from implants an

Define proteins required for underweight - nutritional care, Define Protein...

Define Proteins required for underweight - Nutritional Care? Proteins are required for tissue building, as well as, to take care of the daily wear and tear. Under weight indivi

Transportation of gases in tracheophytes vascular tissues, Is the transport...

Is the transportation of gases in tracheophytes made through the vascular tissues? The Carbon dioxide and The Oxygen are not transported through the xylem or phloem. These gase

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