Metazoa, Biology

Assignment Help:

Metazoa

In the two kingdom classification, the unicellular 'animals' used to be clubbed together under a single phylum Protozoa that constituted sub-kingdom - Protozoa. The rest of the animals, all multicellular, were grouped under the sub-kingdom Metazoa under various phyla (the corresponding grouping for plants was Protophyta and Metaphyta). However, under the present concept of Five Kingdom Classification, this grouping has no relevance. Still, we often continue to use the term Metazoa to refer to the Animalia of the five kingdom classification. In this we start with an explanation of the levels of body organization in animals and the basic animal body plan. However, diverse the different invertebrates and vertebrates may appear to the eye, it is possible to group them in four master body plans.

These are the unicellular plan, the cell aggregate plan, blind sac plan and tube within a tube plan. The protozoan fall into the first category and the rest three structural plans are seen in the metazoans. We next list out the characteristic features of metazoans. We shall also discuss those features that are considered of fundamental importance for describing and understanding the structure and classification of any animal. These characters are:

  • Cleavage patterns and number of germ layers it has been derived from
  • Its body symmetry
  • Nature of body cavity
  •  Segmentation and cephalisation

 


Related Discussions:- Metazoa

Lungs - respiratory organs, Lungs - Respiratory Organs In arachnid art...

Lungs - Respiratory Organs In arachnid arthropods such as scorpion and spider, respiration takes place by means of book lungs. There are four pairs of these structures in the

Which harmone is not associated with male reproduction, Which of the below ...

Which of the below is NOT hormone associated with male reproductive physiology: a) Prolactin b) Testosterone c) Interstitial hormone d) Follicle-stimulating hormone

Mitral valve replacement, Mitral Valve Replacement :  When mitral...

Mitral Valve Replacement :  When mitral valve replacement for a calcified, stenotic valve is done, usually it is a classical procedure removing leaflets, their chordae an

Crustacea, Crustacea The Crustacea show a great morphological diversit...

Crustacea The Crustacea show a great morphological diversity of appendages which may be grouped into three categories, cephalic, thoracic and abdominal. Their appendages are c

Trichomonas vaginalis - protozoan, Trichomonas vaginalis - Protozoan T...

Trichomonas vaginalis - Protozoan This cosmopolitan protozoan lives exclusively in the female vagina and male urethra or prostate. It causes a mild disease called trichomonas

What is procambium, What is Procambium? The procambium produces cells...

What is Procambium? The procambium produces cells that eventually become the vascular tissues xylem and phloem. These primary vascular tissues form a core in the center of th

Osmoregulatory animal, Osmoregulatory Animal An osmoregulatory animal ...

Osmoregulatory Animal An osmoregulatory animal is generally in an osmotic steady state even though there may be hourly and daily variations in osmotic balance. The concentrati

Ribosomes, Ribosomes - It is also known as Protein factory, Engine ...

Ribosomes - It is also known as Protein factory, Engine of the cell. Ribosomes are smallest cell organelles (150 x 250 Å). Unit membrane less cell organelle. Ribo

Virus, what is virus ?? what is classidication , uses , disease of viruses...

what is virus ?? what is classidication , uses , disease of viruses ? what are types of virus ?

Properties of transparency factors in corneal hydration, What are special p...

What are special properties of transparency factors in corneal hydration of cornea? The factors affecting the transparency include special properties of the corneal epitheliu

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