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

Orthopedics, 1. List alternative therapies for musculoskeletal problems. ...

1. List alternative therapies for musculoskeletal problems. 2. What is a xyrospasm? What is the Greek derivative of the word? 3. Name and describe the three types of varus con

Sporophytic and gametophytic self-incompatibility, Sporophytic and Gametoph...

Sporophytic and Gametophytic Self-Incompatibility Besides the categories based on morphology, self incompatibility can be further classified into sporophytic or gametophytic t

What is the meaning of paraplegia, What is the meaning of Paraplegia Pa...

What is the meaning of Paraplegia Paraplegia (from the Greek para, "alongside of," and plegia,  "stroke") is a condition in which both lower limbs are paralyzed (quadriplegia i

Clinical manifestation and diagnosis of pericardiocentesis, Clinical Manife...

Clinical Manifestation Occurs over an extended time period and mimic those of CHF and corpulmonale. Dyspnea on exertion, dependent odema, ascitis, fatigue, anorexia and weight

Diagnosis of diabetes mellitus, Q. Diagnosis of diabetes mellitus? Time...

Q. Diagnosis of diabetes mellitus? Timely and proper diagnosis plays a key role not only in identifying new cases but also in managing old cases with or without diabetic compli

State the principle of adaptation, State the Principle of Adaptation Th...

State the Principle of Adaptation The first principle is that the central goal of assessment is to promote the adaptation of the child, rather than simply to document the prese

What is the criterion used to classify hosts, What is the criterion used to...

What is the criterion used to classify hosts as intermediate hosts or as definitive hosts? The criterion used to classify hosts as intermediate hosts or as definitive hosts is

Explain procedure for isolation of pure culture, Explain Procedure for Isol...

Explain Procedure for Isolation of Pure Culture? Now carry out the exercise following the steps enumerated herewith. 1. Label the name of the organism on the bottom of the p

How establish a pure-breeding population of brown pigs, Would it be possibl...

Would it be possible to establish a pure-breeding population of brown pigs with a few black spots?

Types of blood vessel, Types of Blood Vessel Arteries Arteries ca...

Types of Blood Vessel Arteries Arteries carry blood away form the heart via the pulmonary artery and aorta. Arterioles As major arteries begin to branch , th

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