CBSE Questions for Class 11 Medical Biology The Living World Quiz 16 - MCQExams.com

• Plant taxonomy is the main branches of taxonomy, which refers to the study of plant classification. Classification is keeping objects into groups. Classification involves naming (nomenclature), describing (assigning features to a taxon), and identifying (determining that an unknown element is identical to known one) species.
• The term taxonomy was originally coined by Augustin Pyramus de Candolle in  1813. The founder of plant taxonomy is  Linnaeus, who is credited with the binomial system and classification hierarchy. Hierarchy of categories is the classification of organisms in a definite sequence of categories in a descending order, starting from the kingdom and reaching up to species or an ascending order from species to kingdom.
• A division is a category higher than that of a class. The term phylum is used for animals while division is commonly employed for the plants. A division or phylum is formed of one or more classes. For example, the division of Spermatophyta in plants has similarly 7 classes of gymnosperms and two classes of angiosperms.

• Family names of plants end with suffix 'ae' as depicted in 'Poaceae'.
• Suffix for division is 'phyta', e.g. 'Pteridophyta'.
• Class names for algae end with 'phyceae' while for other plants it ends with suffix 'sida'.
• The suffix used for the genus is 'um'.
• So, the correct answer is 'Class - Bryopsida - phyta'.

• Wheat belongs to order 'Poales'and mango belongs to order 'Sapindales'.
  
• House fly belongs to order 'Diptera' and  man belongs to order 'Primata'.

• Photoperiod affects the reproduction in plants by regulating the flowering timing of the plants.
  
• The binomial system of nomenclature was given by Carolus Linnaeus. R. H. Whittaker proposed 5 kingdom classification of living organisms.
  

• Ernst Mayr proposed the concept of biospecies. 
• According to this concept of Mayr, all the members that can interbreed among themselves and can produce fertile offspring are the member of same species. 
  
• According to Mayr, the words 'reproductively isolated' are the key words of the biological species. 
  

$$\textbf{Correct answer: C}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ Based on the taxonomic hierarchy, the phylum is close to kingdom and class. Multiple phyla form a given kingdom and multiple classes form a single phylum.

$$\textbf{Option (B):}$$ 

$$\bullet$$ Class is close to order and phylum. Multiple orders together form a class and multiple classes together form a phylum.

$$\textbf{Option (C):}$$ 

$$\bullet$$ The closest categories to family are order and genus. This is because multiple families together form an order.

$$\bullet$$ This is why an order will be the closest of all the taxonomic hierarchies.

$$\textbf{Option (D):}$$ 

$$\bullet$$ Species is the lowest rank in the taxonomic hierarchy and the only close category with it is the genus.

Hence, the correct answer is option (C).

• Biodiversity refers to all the variety of life that can be found on Earth (plants, animals, fungi, and micro-organisms) as well as to the communities that they form and the habitats in which they live.
• Fungi have the greatest biodiversity it anywhere (even on bread) grows without seeds and flowers.
• The angiosperms are diversified due to their many mutualistic relationships with pollinators, fungi, herbivores, and others. 
• Algal diversity is estimated at the levels of the richness of species and of higher taxonomic ranks and as the variety of habitats algae dominate and their functional importance in the processes they mediate.
  
• The pteridophytes are the oldest land plants on earth. They are mostly a dominating and diverse group of pteridophytes throughout the world and include 300 genera and 12000 known species.
• So, the correct answer is option D.

• Alpha diversity is the number of species found in a particular area or ecosystem.
• Beta diversity is the variation of the species composition between two habitats or regions. It takes into account the alpha diversity of the habitats and the number of unique species in each habitat. 
• Gamma diversity is a measure of the overall number of species (the diversity) within a region. It is basically the sum of all the species of all habitats within the region of interest. 

• Selective pressures drive natural selection.
•  Some members of the population will not survive and reproduce and, thus, will not pass on their genes into the next generation. This change in the genetic makeup of a population is called evolution. 
• Hence, Environmental selective pressure will not affect the frequency of the gene in a large population. 
• So, the correct answer is 'Environmental selective pressure'.