Characteristics of metazoa, Biology

Characteristics of Metazoa

The unicellular protozoans are highly versatile and successful organisms that show remarkable organization and division of labour within the confines of the single cell. This diversity is achieved by varying the structure of their organelles at the sub-cellular level. The Metazoa or the multicellular animals have achieved their structural diversity by varying their cells that have become specialized to perform different functions. These cells are normally incapable of independent existence. Let us list out some of the features that characterize metazoans.

1. Members of Metazoa possess a complex multicellular structural organization which may include the presence of tissues, organs and organ systems.

2. In the life history of metazoans, typically a fertilized egg passes through a blastula stage in the course of its early embryonic development before changing into an adult.

3. Since metazoans are multicellular they are relatively larger in size than unicellular protozoans. Naturally, their nutritional requirements are more and they have to search for food. Consequently, locomotion in metazoans is highly developed and for this purpose they have evolved contractile muscular elements and nervous structures.

 4. The ability for locomotion has influenced the shape of the metazoan animals which in turn has conferred specific types of symmetries to metazoan groups.

5. Most of the metazoans show differentiation of the anterior end or head (cephalization); associated with cephalisation, there is the centralization of the nervous system in the head region. Although all metazoans share some characteristic features, their body plans differ in symmetry, internal organization, developmental patterns and modes of formation of, body cavity. These differences provide us a means of grouping them or organising them into different phyla. Let s discuss these features one by 'one.

Posted Date: 1/15/2013 1:24:32 AM | Location : United States







Related Discussions:- Characteristics of metazoa, Assignment Help, Ask Question on Characteristics of metazoa, Get Answer, Expert's Help, Characteristics of metazoa Discussions

Write discussion on Characteristics of metazoa
Your posts are moderated
Related Questions
9. A simple and inexpensive screening method has been developed to identify individuals with HIV infection at routine medical check-ups. To study the sensitivity and specificity, t

Describe Systolic Sounds in heart dieases? Early Systolic Sounds: Aortic or pulmonary ejection sounds are the most common early systolic sounds. These are high frequency soun

Explain the Fluoride Toxicity? Fluoride is a cumulative toxin. Ingestion of fluoride 1.0-1.5 mg/L for several years may produce dental fluorosis, i.e. browning and pitting of t

Conservation of biodiversity is very important to maintain the ecological balance of ecosystem. Various steps for conservation of biodiversity: 1.           Creation of consc

Q. Demonstrate the counselling process in the form of role play? Role playing refers either to the unconscious changing of one's behavior to assume a social role or roles in lif

Q. How is the circulatory system of reptiles characterized? What is the basic difference between the amphibian and the reptile heart? The circulatory system of beings of the cl

Q. Is the esophagus a muscular organ? Why even in a patient lying totally flat on a hospital bed can the swallowed food reach the stomach? The esophagus is a predominantly musc

Severe Acute Respiratory Syndrome (SARS) After travelers' diarrhea, respiratory infection is the most common infectious disease affecting travelers. In the winter of 2003 a ne

Precautions to prevent from HIV  To avoid HIV infection one should practice safe sex (use of condoms). Besides a few simple precautions are given for protection against HIV inf

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4