Classification and diversities in Living Organisms

Introduction

     Every organism whether plant or animal is unique in itself. There is a wide diversity in the flora (plants) and fauna (animals) in the world.

Importance of Classification

     By making a comparative study and assorting the similarities and differences amongst the various varieties of species, organisms can be classified into groups or sets.

Nomenclature

     Carl Linnaeus, father of modern botany, was a Swedish naturalist who laid the foundation of modern classification and nomenclature in 1758.

Classification of Plants and Animals

     Cellulose cell wall surrounds the cell membrane.Cell wall is absent in animal cells.

Plant Kingdom

     The plant body is not differentiated into stem, root and leaves but is in the form of an undivided thallus.

Animal Kingdom

     The Animal Kingdom is divided in several phyla mainly on the basis of the cell organisation, symmetry, presence or absence of notochord and body cavity.

Phylum Protozoa (Primitive Animals)

     Unicellular (single celled) animals.Nutrition is heterotropic.

Phylum Porifera (Sponges)

     The simplest multicellular animals. The cells are loosely held together and do not form tissues.

Phylum Coelenterata (Cridaria)

     The simplest multicellular animals. The cells are loosely held together and do not form tissues

Phylum Platyhelminthes (Flatworms)

     Simplest triploblastic organisms showing bilateral symmetry.Mostly parasites in other animals.

Phylum Aschelminthes (Round or Thread Worm)

     Mostly parasites in other animals.Parasitic or free living.

Phylum Annelida (Segmented Worms)

     Body is covered by a non-chintinous cuticle which may have chitinous setae, or parapodia.

Phylum Arthropoda (Animals with Jointed Legs)

     Body is bilaterally symmetrical and segmented. It is divided into head, thorax and abdomen.

Phylum Mollusca

     Body is soft and divided into three regions (head, dorsal visceral mass and ventral foot).

Phylum Echinodermata

     Body is radially symmetrical, star shaped, spherical or elongate, Exoskeleton is spiny.

Phylum Hemichordata

     Have characteristics of both invertebrate and chordate.

Phylum Chordata

     Phylum Chordata is characterized by three unique features, at least during the early stages of their development.

Question and Answers

Question and Answers 1

Question and Answers 2

Question and Answers 3

Multiple Choice Questions