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Showing posts from September, 2019

Eyes: How They Work, Anatomy and Common Condition

 The eye is a complex sensory organ that allows us to see the world around us. The eye works by gathering light from the environment and converting it into electrical signals that can be interpreted by the brain. The basic structure of the eye includes the cornea, iris, pupil, lens, retina, and optic nerve. The cornea is the transparent outer layer of the eye that helps to focus incoming light. The iris is the colored part of the eye that regulates the amount of light that enters the eye through the pupil, which is the black circular opening in the center of the iris. The lens is a clear, flexible structure located behind the iris that helps to focus light onto the retina. The retina is a thin layer of tissue that lines the back of the eye and contains photoreceptor cells called rods and cones. These cells convert light into electrical signals that are sent to the brain via the optic nerve. The rods are responsible for the low light vision and detecting motion, while the cones are resp

HISTORY OF CLASSIFICATION OF ORGANISMS

In previous decades there are many scientists came who gave different - different classification of organisms. Some of them are discussed here. (1) Aristotle :  Aristotle was the father of biology and father of zoology. He was the Greek political philosophers. He classified plants on the basis of morphological character (growth habit) in three groups : Trees Shrubs Herbs (2) Theophrastus (371 - 287 B.C.) :  He is known as father of ancient plant taxonomy and father of botany. He was also the Greek political philosophers. Theophrastus wrote book on plants named Historia plantarum . He also proposed the term Annual, Biennial and Perennial. He gave the artificial classification of plants. He classified plant kingdom in to four groups on the basis of growth habit : Trees Shrubs Under shrubs Herbs (3) Carolus Linnaeus (1707 - 1778) :  His real name was Carl Von Linne . On the basis of work in Latin language, he changed his name to Carolus Linnaeus. He w

PLANT TAXONOMY

Taxonomy consist of two words "Taxis" means arrangement and "nomos" means law and together we will called it law of arrangement or classification. The word taxonomy was proposed by A.P.de. Candolle in his book "Theories elementaire de la botanique" (Theory of elementary botany). Taxonomy includes study of following points : Identification : A process by which an organism is recognised  from the other already known organisms and is assigned to a particular taxonomic group is called identification. Nomenclature : Naming of organisms according to international scientific rules is called nomenclature. Classification : A process by which any organism is grouped into convenient categories on the basis of some easily observable characters. In modern taxonomical studies, taxonomists use external and internal structure structure, along with the structure of cell, development process and ecological information of organisms. The number of species tha