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

Explain radial symmetry in classification animal kingdom, Explain Radial S...

Explain Radial Symmetry in Classification of the Animal Kingdom? All of the animals besides the sponges are considered to belong to the Eumetazoa, or the "true animals" because

Why is blood important for larger animals, Q What is the alternative means ...

Q What is the alternative means for transport of substances in animals without a circulatory system? Why is blood important for larger animals? In animals that don't present th

Can you describe about hematosis, Q. What is hematosis? In humans where doe...

Q. What is hematosis? In humans where does hematosis occur? Hematosis is the oxygenation of the blood, venous blood (oxygen-poor) after hematosis is transformed into arterial b

Limiting factor - ecosystem, Limiting Factor - Ecosystem In all ecosys...

Limiting Factor - Ecosystem In all ecosystems one factor, usually abiotic, limits the growth of organisms and is therefore called a limiting factor. The limiting factor is one

Causes of diabetic ketoacidosis, Q. Causes of Diabetic Ketoacidosis? Th...

Q. Causes of Diabetic Ketoacidosis? The causes of Diabetic Ketoacidosis (DKA) are the following: - Missing of insulin injection - Infection - Trauma (injury) - Myoc

Birth and developmental history -assessment, Birth and Developmental Histor...

Birth and Developmental History -Assessment  Collection of information regarding a child's early development usually begins with the mother's pregnancy, labour and delivery, an

What are the chief complaint and patient expectations, Chief Complaint and ...

Chief Complaint and Patient's Expectations It is extremely vital to know what the patient really wants. 1. The chief complaint should be recorded in patient's own words as f

Sex, pls enlighten me

pls enlighten me

Agro industrial-molybdenum, Molybdenum Although molybdenum functions as a ...

Molybdenum Although molybdenum functions as a component for the enzymes xanthine oxidase, sulfite oxidase and aldehyde oxidase, requirements for it are not established. Molybdenum

Demonstrate the cause of the mutant trait, A protein that is normally a sin...

A protein that is normally a single-pass transmembrane protein is absent from the cell surface of the mutant cell line YTM-15. When labeled so that the protein can be localized, yo

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