In biology, kingdom (Latin: regnum, pl. regna) is a taxonomic rank, which is either the highest rank or in the more recent three-domain system, the rank below domain. Kingdoms are divided into smaller groups called phyla (in zoology) or divisions in botany.
Currently, textbooks from the United States use a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea, and Bacteria) while British, Australian and Latin American textbooks may describe five kingdoms (Animalia, Plantae, Fungi, Protoctista, and Prokaryota or Monera). Some recent classifications have explicitly abandoned the term “kingdom”, noting that the traditional kingdoms are not monophyletic, i.e. do not consist of all the descendants of a common ancestor.
1 Definition and associated terms
2 Systems of classification
2.1 An initial dichotomy: Two kingdoms
2.2 An increasing number of kingdoms
2.2.1 Three kingdoms
2.2.2 Four kingdoms
2.2.3 Five kingdoms
2.3 Recent developments: six kingdoms or more than? Continue reading
Question 1. What are the difficulties that you would face in classification of animals, if common fundamental features are not taken into account?
Answer: Common fundamental features help grouping animals in certain categories or sub-categories. For the common fundamental feature of all the Arthropods is joined legs for locomotion. Higher animals, like mammals too have joined legs but the difference is the absence/presence of muscles to facilitate articulation. Similarly, all birds have fore-limbs modified to assist in flying. This gives us one clue to categorise a particular animal among aves.
Had we not used fundamental features we could not get a point to start with. Fundamental features help us further pin point the characteristics for classification and identification.
Question 2. If you are given a specimen, what are the steps that you would follow to classify it?
Answer: Steps to Follow for Classification: Continue reading