Living World

• Living organisms were perceived differently by early man compared to inanimate matter
• Early man deified some inanimate matter and some animals and plants
• A common feature of inanimate and animate objects was the sense of awe or fear they evoked
• Description of living organisms, including human beings, began later in human history
• Societies with an anthropocentric view of biology made limited progress in biological knowledge
• Systematic and monumental description of life forms led to detailed systems of identification, nomenclature, and classification
• Recognition of similarities among living organisms horizontally and vertically humbled man and led to cultural movements for conservation of biodiversity
• Living organisms can be classified into different taxa based on characteristics
• Taxonomy involves characterisation, identification, classification, and nomenclature of organisms
• External and internal structure, cell structure, development process, and ecological information are essential for modern taxonomic studies
• Human interest in organisms and their relationships led to the branch of study known as systematics
• Systematics is the branch of study that focuses on the systematic arrangement of organisms
• Linnaeus used Systema Naturae as the title of his publication
• The scope of systematics includes identification, nomenclature, and classification
• Systematics takes into account evolutionary relationships between organisms
• Classification involves a hierarchy of steps, with each step representing a rank or category
• Taxonomic categories and hierarchy can be illustrated by examples such as insects, which share common features like three pairs of jointed legs
• Taxonomic categories include kingdom, phylum (or division for plants), class, order, family, genus, and species
• Species are groups of individual organisms with fundamental similarities, distinguished from closely related species based on distinct morphological differences
• Genus comprises a group of related species with more characters in common compared to species of other genera
• Family consists of related genera with fewer similarities compared to genus and species
• Order is an assemblage of families with a few similar characters
• Class includes related orders, such as order Primata and order Carnivora in class Mammalia
• Phylum includes classes of animals like fishes, amphibians, reptiles, birds, and mammals, all included in phylum Chordata based on common features like the presence of notochord and dorsal hollow neural system
• Kingdom is the highest category, with animals belonging to Kingdom Animalia and plants to Kingdom Plantae
• Taxonomic categories from species to kingdom are shown in ascending order, with lower taxa sharing more common characteristics
• Taxonomists have developed sub-categories in the hierarchy to facilitate more scientific placement of various taxa