Tag: plant taxonomy

Bessey considered spermatophyta as having a polyphyletic origin, being composed by three different phyla, of which he only treated angiosperms. The most primitive, original flower had many separate petals, stamens and carpels. As they evolved, the parts of the flowers either fused together, reduced or became absent. The simple structures are not primitive, but have become simple as a result of a reduction from more complex parts. An example of the primitive flower would be the Ranunculus, buttercup flowers. A more advanced type of flowering plant would be the catkin inflorescences.

Darwin proposed the theory of natural selection to explain the process of evolution. Natural selection refers to unequal ability of individuals to survive and reproduce based on suitability of their inherited characters to prevailing environmental conditions; option D is incorrect. According to inheritance of acquired characters, a theory given by Lamarck, individual acquire characters under influence of needs as posed as changing environmental conditions; these characters are inherited. He explained evolution the long-necked giraffes from short-necked giraffes on the basis of his theory; option B is incorrect. John Ray proposed the typological species which is defined as a group of organisms that are morphologically similar irrespective of their breeding compatibility. It determines species as a static entity which can interbreed within their limit of variations and hence, is also termed as static concept; option A is incorrect. Haeckel coined the term phylogeny to refer study of ancestral relationship, lineages and that of evolutionary history of a taxonomic group; he built the first genealogical tree of life and proposed the biogenetic law which states that ontogeny repeats phylogeny. Here, ontogeny refers to life history of an individual and phylogeny is the history of evolution of the individual; option C is correct. Thus, the correct answer is option C.

Taxonomy is the branch of science that deals with principles, rules and procedure of classification of organisms based on their similarities and dissimilarities. 

Taxonomy is the branch of science that deals with principles, rules and procedure of classification of organisms based on their similarities and dissimilarities. Since identification and nomenclature is the prerequisite for classification; the first step in taxonomy is identification followed by nomenclature and then classification. So, option A is the correct answer. 

The term phylogeny deals with the study of the evolutionary history of an organism. The classification which is based on the evolutionary relationship of organisms is referred to as phylogenetic classification. The evolutionary changes, lineage and history are taken into account during the classification.  

Taxon represents taxonomic group of any rank. Each plant belongs to a hierarchy of taxa which are assigned taxonomic ranks. For example, different taxa for onion are Allium cepa (species rank), Allium (genus rank), liliaceae (family rank), thus Allium cepa, Allium, liliaceae are different taxa to which onion belongs. 

Linnaeus is considered as the father of taxonomy and was first to use the binomial nomenclature for organisms. He proposed natural system of classification for living organism and divide them into plant and animal kingdom; his system was first described in Systema Naturae in which he described all known species of plant and animal. Linnaeus described plant genera known to him in Genera Plantarum. He described all plant species known to him in his book Species Plantarum in which he gave a generic name to each species.