Chordata and its characteristics, Biology

Phylum Chordata-

Chordata name given by Balfour.

Herst put hemichordata into separate phylum. Lamarck gave the word tunicata & vertebrata.

Pisces classified by Romer. Amphibia classified by G.K. Noble.

There are 65,000 species of chordata.

Pisces is largest class, having 33,000 species. Amphibia is smallest class having 2500 species.

CHARACTERS OF CHORDATA -

1.      Total animals are 3-5% of animal kingdom. Notochord or chorda dorsalis present in any stage of life cycle.

2.      Gill slits present in any stage of life cycle. Nervous system is dorsal, single & hollow. Post anal tail present.

3.      Mouth after first segment. Anus before last segment.

4.      Liver is present. Heart is ventrally placed.

5.      Flow of blood on dorsal side, anterior to posterior. Flow of blood on ventral side, posterior to anteriror.

6.      R.B.C. present. Circulatory system closed. Alimentary canal is placed ventral to nerve cord.

7.      Symmetry bilateral. Organ system grade. Triploblastic animals. True coelomate. Enterocoelic

8.      Unisexual. Sexual reproduction present. Larvae generally absent.

9.      Power of regeneration less. Cold blooded / warm blooded.

10.     Portal system present.

629_chordata.png Chordata is divided into 2 parts -

1. Protochordata              2. Vertebrata

 

S.No.

Character

Protochordata

Vertebrata

 

1

 

2

3

4

5

6

 

Notochord or chorda dorsalis

 

Habitat

Feeding

Evolution

Size

Endostyle

 

Present in original form

 

Marine

Cilliary

Early

Small

Present

 

Converted into vertebral column & cranium

 

All habitats

May be

Late

Large

Thyroid gland present

Posted Date: 10/1/2012 1:23:01 AM | Location : United States







Related Discussions:- Chordata and its characteristics, Assignment Help, Ask Question on Chordata and its characteristics, Get Answer, Expert's Help, Chordata and its characteristics Discussions

Write discussion on Chordata and its characteristics
Your posts are moderated
Related Questions
Self-Pollination - Types of Pollination Self-pollination refers to the transfer of pollen grains from the anther to the stigma of the same flower. In chasmogamous flowers the

The vitamin niacin is a necessary component of NAD. Niacin can be consumed in food or manufactured in the body from tryptophan, an amino acid. How would a person's ability to break

Q. What is the life cycle of the gymnosperms? As all plants they present a diplobiontic life cycle that is alternation of generations with haploid and diploid stages and the la

Genital warts and human papillomavirus (hpv) infection External genital warts are caused by human papillo- mavirus, usually type 6 or 11; other types (16, 18 and others) cause

Q. The vascular lesions caused by leeches upon the blood vessels of their host cause blood naturally to coagulate. How does the leech solve this problem since it could be expected

Q. What are the main prophylactic measures against hookworm disease? The major prophylactic measures against hookworm disease are to avoid walking barefoot on soils suspected o

Sound is a main mean of communication and entertainment and is also very effective alarm system for some animal. A loud and unwanted or unpleasant sound causes discomfort and is ca

Q. How is the chromosome region where the centromere is located called, and how chromosomes classified in the relation to the position of their centromere? The chromosome regio

Q. Why iodine is vital for human beings? Iodine is a essential chemical element for the proper functioning of the thyroid since it is part of the hormones produced by this glan

porifera canal system skeleton