What are Metazoans? Metazoans can be define as multicellular organisms or as cellular animal or more accurately simply as animals.They are holozoic multicellular organisms. Which are develop from embryo. Their body cells are generally organized in tissues and organs. [exception, porifera have cellular level of organization and coelenterates have tissue level of organization.] There gametes […]
What is a species? A group or class of animals or plants (usually constituting a subdivision of a genus) having a certain common and permanent characterstics which clearly distinguish it from other groups. BIOLOGICAL SPECIES CONCEPT REPRODUCTIVE ISOLATING MECHANISM PRE-ZYGOTIC POST-ZYGOTIC ECOLOGICAL HYBRID INVIABILITY TEMPORAL STERLITY BEHAVIORAL (barriers to isolation) REDUCED FITNESS OF HYBRID OFFSPRING
The history of biological classification states that the Greek philosopher Aristotle categorized many creatures according to their environment, traits, etc. Later, in the 18th century, Swedish botanist Carolus Linnaeus established the Taxonomic Hierarchy Categories, a classification scheme that is still in use today.
Wastebasket taxon (also called a waste-bin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon intended to classify organisms that do not fit anywhere else. They are generally defined by designated members, often superficial resemblance to each other, lack of one or more distinct trait states, or non-membership of one
