8th Class Science Cell - Structure and Functions Multicellular Organism

     Multicellular Organism

The organisms made up of more than one cell are called multicellular organisms. These organisms have specialised cell structures for performing different types of functions. Multicellular organisms are either unisexual or bisexual. The bisexual organisms are called hermaphrodite, in which both the male and female sex are present.

A living example of the attempts to become multicellular organism is represented by the slime moulds, which are transformed from single cells to multicellular organism under adverse condition. Another example is found among the green alga Volvox and its relatives. The ranges of sizes goes from the single cell Chlamydomonas to the 16-cell Gonium, Eudorina and finally to the largest species of viovox, which may consist of 50000 or more cells. Biologists have thought that new genes would be required for the transition to multicellularity. But a comparison between the genomes of the 2000-cell volvox carten and a single celled chlamydomonas indicates that the biological complexity can arise without major changes in genome content..

Multicellular Organism      

       All the higher organisms are made up of more than one cell. All the multicellular organisms have specialized organs for the specific functions. But there are some organs in the body of organisms, which are functionless or useless. Name the vestigial organ in the body.

(a) Vermiform Appendix

(b) Hum

(c) Caecum

(d) Taenia

(e) None of these

Answer: (a)

Explanation

The vestigial organ in the human is vermiform Appendix.

         Which organism is transformed from single cellular to multicellular in adverse condition?

(a) Gonium

(b) Edorina

(c) Volvox

(d) Slime moulds

(e) None of these

Answer: (d)

Explanation

The organism which gets transformed from singular cellular to multicellular is slim moulds..