Tag: kingdom plantae

• Modern taxonomy is based on the hypotheses' of the evolutionary history of organisms, known as Phylogeny. As with the scientific method, scientists develop a hypothesis on the history of an animal and utilize modern science and technology to prove phylogeny.
• With the advent of such fields of study as phylogenetics, cladistics, and systematics, the Linnaean system has progressed to a system of modern biological classification based on evolutionary relationships between organisms, both living and extinct.
• So the correct option is 'phylogeny'.

Plants exhibit sensitivity and irritation but sensor organs are absent.

So, the statement is ‘True’.

Ther term taxonomy is introduced by Carl Linnaeus. He is called as the father of taxonomy. He developed taxonomic hierarchy. It is also called as Linnaeus hierarchy. In it, domain is the highest rank followed by kingdom, phylum, class, order, family, genus, and species. Species is the lowest rank in the hierarchy. 

Artificial systems of classification were based upon vegetative and sexual characteristics, where both vegetative and sexual characteristics were given equal weightage. It was not acceptable because vegetative characters are more easily affected by environment.

Classification based on evolutionary relationships of organisms is called phylogenetic system of classification.

Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and small (micro) spores are known as heterosporous. Microspore and macrospore germinate and gives rise to male and female gametophyte respectively. The female gametophytes in these plants are retained on the parent sporophyte for a variable period. The development of the zygote into young embryo takes place within the female gametophytes. This event is a precursor to the seed habits considered an important step in evolution. So, the correct answer is 'Embryo develops in female gametophyte which is retained on parent sporophyte'.

Selaginella is a pteridophyte also known as spike moss or little club moss. It is a tropical plant. It has world wide distribution. It grows in damp forests. Some species occur in temperate regions. They grow in moist shady places. In Selaginella male gametes are spindle shaped and biflagellate. Hence option D is correct.

Selaginella is a genus of primitive vascular plants in the family Selaginellaceae. Selaginella has a tendency to form seed because the retention and germination of single megaspore within megasporangium to form a female gametophyte led to the phenomenon of seed habit, a characteristic feature of spermatophytes.

Selaginella exhibits heterospory, endosporic development, reduced gametophytes, and strobilus formation, which are considered advanced evolutionary traits in pteridophytes.