Tag: biology

Carlolus Linnaeus is well known for his work in binomial nomenclature. Binomial nomenclature is a naming system for the classification of species. In this, organism is given a scientific name. For example, the scientific name of human is Homo sapiens. In this, Homo is genus which includes early and modern humans and sapiens is species specific for humans

• Both John Ray and Linnaeus proposed Morphospecies concept.
  
• Morphological Species Concept characterizes a species by body shape and other structural features and is applied to asexual and sexual organisms. It differs from the modern concept of species where a group of organisms capable of interbreeding and producing fertile offspring are said to belonging to same species. 
  
• Darwin proposed the theory of biological evolution.

Taxonomy is defined as the description, identification, nomenclature, and classification of organisms. Carolus Linnaeus is known as the father of taxonomy.

Artificial systems of classification were based upon morphological characters {such as habit, habitat, colour, number and shape of leaves, etc.) for grouping of organisms. They were mainly based on vegetative characters or on the androecium structure. These systems separated the closely related species since they were based only on a few characteristics.

Species Plantarum, (1753), two-volume work by the Swedish botanist Carolus Linnaeus, in which he established a precise and workable two-word, or binomial, system for naming plants. This system forms the basis of modern plant taxonomy. In this master work Linnaeus described 6,000 species of plants and assigned each plant a genus name and a species name, the genus representing a group of plants, the species designating specific individuals within a given genus. Species Plantarum was the first work that consistently applied a referable system of nomenclature; it was a vast improvement over the cumbersome polynomial descriptions generally used before its publication. The first edition of Species Plantarum (with the 1754 edition of an earlier work, Genera Plantarum) has been internationally accepted as the starting point in the nomenclature of flowering plants and ferns.

Taxonomic keys are specific to each taxonomic category. A separate key is required for each rank (e.g., family, genus, species) because the diagnostic characters vary significantly between levels.

Aquatic plants respire and dispose of wastes by diffusion. Diffusion is a process by which oxygen and nutrients dissolve in water and reach aquatic plants. The waste materials diffuse out of the plants as diffusion takes place from higher concentration to lower concentration. Shedding of leaves occurs in deciduous trees. The process of getting rid of excess water in form of water vapour is called transpiration. 

The plants secrete many materials as the by-products of reactions and metabolic processes.

Plant roots excrete a variety of organic compounds to the soil such as sugars, amino acids, organic acids and phenols. Organic acids are usually present in root exudates and they seem to be part of a nutrient mobilization strategy. For example, oxalic acid is most efficient for phosphorus mobilization, while citric and malic acids are more efficient with iron. Water, oxygen and calcium carbonate are not excreted by plant roots. 

Tannins are secondary metabolites produced by plants. They are typically stored in the bark, wood, and leaves of trees to protect against herbivores and pathogens.