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

Mode of nutrition, What is the mode of nutrition of Ascaris?

What is the mode of nutrition of Ascaris?

Explain the importance of biochemical tests, Explain the Importance of Bioc...

Explain the Importance of Biochemical Tests? Specific series of biochemical tests have been developed for fast identification of microorganisms in laboratories. These biochemic

Definition of probiotics and prebzotics, Definition of probiotics and prebz...

Definition of probiotics and prebzotics? An early definition of probiotics is 'organisms and substances which contribute to intestinal microbial balance'. Later the word 'subst

What is the general chemical equation of photosynthesis, What is the genera...

What is the general chemical equation of photosynthesis? Why doesn't that equation clearly show the real origin of the molecular oxygen liberated? The general equation of photo

What is osmotic pressure, Q What is osmotic pressure? Osmotic pressure ...

Q What is osmotic pressure? Osmotic pressure is the pressure produced in an aqueous solution by a region of lower solute concentration upon a region of higher solute concentrat

What is a provirus, It is the DNA representing, the genome of virus that ha...

It is the DNA representing, the genome of virus that has been included into the DNA of the host.

When the plant transpiration increases, When air humidity is high does the ...

When air humidity is high does the plant transpiration increase or lower? When air humidity is high transpiration diminishes. As transpiration is a simple diffusion process it

Show the peptide found in the brain, Q. Show the Peptide found in the brain...

Q. Show the Peptide found in the brain? There are as many as 300 peptide neurotransmitters found in the brain. Peptide is a short protein consisting of fewer than 100 amino aci

Contraceptive pill - reproduction, Contraceptive Pill - Reproduction ...

Contraceptive Pill - Reproduction About sixty million women in the world are currently using oral steroid contraceptives. These contraceptives usually consist of a synthetic

Osmotic function - essential elements, Osmotic Function - Essential Element...

Osmotic Function - Essential Elements Plant cells generally contain mineral ions 10 to 1000 times higher in concentration than the surrounding soil. That is why water enters t

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