Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy.
Modern biological classification has its root in the work of Carolus Linnaeus, who grouped species according to shared physical characteristics. These groupings have since been revised to improve consistency with the Darwinian principle of common descent. Molecular phylogenetics, which uses DNA sequences as data, has driven many recent revisions and is likely to continue to do so. Biological classification belongs to the science of biological systematics.
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Key topics[show]Introduction to evolution
Evidence of common descent
Processes & outcomes[show]Population genetics
Variation • Mutation
Natural selection • Adaptation
Genetic drift • Gene flow
Speciation • Adaptive radiation
Co-operation • Coevolution
Divergent • Convergent
Natural history[show]Origin of Life • History of life
Timeline of evolution
Biodiversity • Biogeography
Classification • Cladistics
History of Evolutionary theory[show]Overview
Timeline of paleontology
History of paleontology
Renaissance and Enlightenment
Darwin • On the Origin of Species
Before the Synthesis
Modern evolutionary synthesis
Molecular evolution • Evo-devo
Fields Classification of animals
The Classification of animals :
Animal Kingdom can be split up into main groups, vertebrates (with a backbone) and invertebrates (without a backbone). When you think of an animal, you usually think of something like a cat, a dog, a mouse, or a tiger.
All told, around 800,000 species have been identified in the Animal Kingdom -- most of them in the Arthropod phylum.
In fact, some scientists believe that if we were to identify all species in the tropical rain forests the ranks of Arthropoda would swell to over 10 million species! Most people do not normally think of a clam, a jellyfish, or an earthworm as an animal.
Yet all of them belong to the kingdom of animals. The science of classifying organisms is called taxonomy.
In order to study living things, scientists classify each organism according to its:
Usually, a species is called by its genus name (capitalized) followed by its species name (lower case), so a human being is called Homo sapiens. In Latin that means "wise man."
To date there are five kingdoms: Animalia, which is made up of animals; Plantae, which is made up of plants; Protista, which is made up of protists (single-celled creatures invisible to the human eye); Fungi, which is made up of mushrooms, mold, yeast, lichen, etc; and Monera, which is made up of the three types of bacteria.
The next category is the Phylum. There are several phyla within each kingdom. The phyla start to break the animals (or plants, fungi, etc) into smaller and more recognizable groups. The best known phylum is Chordata, which contains all animals with backbones (fish, birds, mammals, reptiles, amphibians). There is also Arthropoda (insects, spiders, crustaceans); Mollusca (snails, squid, clam); Annelida (segmented worms); Echinodermata (starfish, sea urchins) and many, many more.
The next category that makes up the phyla is the Class. The class breaks up animals into even more familiar groups. For example, the phylum Chordata is broken down into several classes, including Aves (birds), Reptilia (reptiles), Amphibia (amphibians), Mammalia (mammals) and several others.
The next category is the Order. Each class is made up of one or more orders. Mammalia can be broken down into Rodentia (mice, rats), Primates (Old- and New-World monkeys), Chiroptera (bats), Insectivora (shrews, moles), Carnivora (dogs, cats, weasels), Perissodactyla (horses, zebras), Artiodactyla (cows), Proboscidea (elephants) and many more.
Orders can then be broken down into Families. The order Carnivora can be broken down into Canidae (dogs), Felidae (cats), Ursidae (bears), Hyaenidae (hyaenas, aardwolves), Mustelidae (weasels, wolverines), and many more.
The next category is the Genus. The family Felidae, for example, can be broken down into Acinonyx (cheetah), Panthera (lion, tiger), Neofelis (clouded leopard) and Felis (domestic cats).
Finally, the genus is broken down into the Species. The genus Panthera can be broken down to include Panthera leo (lion) and Panthera tigris (tiger). Note that the genus is placed in front of the species.
Main group of Invertebrates are :
The largest and most commonly studied phyla of animals are:
Cnidaria (jellyfish, hydras, sea anemones, Portuguese man-of-wars, and corals)
Platyhelminthes (flatworms, including planaria, flukes, and tapeworms)
Nematoda (roundworms, including rotifers and nematodes)
Mollusca (mollusks, including bivalves, snails and slugs, and octopuses and squids)
Annelida (segmented worms, including earthworms, leeches, and marine worms)
Echinodermata (including sea stars, sea cucumbers, sand dollars, and sea urchins)
Arthropods (including arachnids, crustaceans, millipedes, centipedes, and insects)
Chordata (animals with nerve chords - this group includes the vertebrates)
KINGDOM NR.OF SPECIES
Protoctists (algae, protozoa, etc)......... 80,000
Animals, vertebrates........................... 52,000
Animals, invertebrates.................... 1,272,000
Total number of described species... 1,750,000
Possible nr. with unknown species: 14,000,000
from the United Nations publication: UNEP-WCMC (2000). Global Biodiversity: Earth's living resources in the 21st century. Cambridge, World Conservation Press.
The Animal Kingdom is at once the Kingdom most and least familiar to us. Almost all of the animals we commonly think of -- mammals, fish, and birds -- belong to a single subgroup within one of the 33 Phyla comprising the Animal Kingdom. On the other hand, over 100,000 species in some 25 animal phyla -- mostly small worms -- are so unfamiliar that they are virtually unknown to non-scientists. The same goes for several hundred thousand tiny insect-like species populating the Arthropoda phylum.
Scientists who study living things are called biologists. Biologists classify living things into two kingdoms, the Plant Kingdom and the Animal Kingdom. The study of plants is called botany. Scientists who study plants are called botanists. The study of animals is called zoology. Scientists who study zoology are called zoologists. Zoologists study thousands of different kinds of animals. ~Article by By Prof. R. Shetty