CBSE Questions for Class 11 Medical Biology The Living World Quiz 7 - MCQExams.com

• Species, the basic unit of classification in the hierarchical taxonomic system. A species is a group of similar organisms sharing a common gene pool and interbreeding freely, producing fertile offspring. Species occur in the form of many interbreeding groups called populations.
• A species don't interbreed with other species in nature, interbreeding of the organisms of same species produces fertile offspring,  whereas interbreeding of different species produces sterile offspring. For example, horses and donkeys can interbreed, producing mules. Mules can't reproduce because of horses and donkeys are not same species, while they are close enough to interbreed, their offsprings are sterile.
• They remain isolated and can be distinguished from one another in specific characteristics.

• A phylogenetic tree or evolutionary tree is a branching diagram or "tree" showing the evolutionary relationships among various biological species or other entities—their phylogeny—based upon similarities and differences in their physical or genetic characteristics.
  
• In trees, two species are more related if they have a more recent common ancestor and less related if they have a less recent common ancestor.
  
• Modern biologists prefer to perceive the phylogenetic tree of organisms as multibranched, rather than linear, with no particular species being "higher'', superior is a true statement.
  
• So, the correct answer is 'True'

• The Himgiri is the resistant variety of Wheat plant which is resistant to the hill bunt disease. 
• The pollen grains of this plant are known to lose their viability within 30 minutes of their release. 
• The wheat plant belongs to the order Poales and so the taxon of this plant is considered as Poales. 

• The most accurate classification of organisms under 5 kingdom classification was given by R.H. Whittaker.
  
• The 5 kingdoms included were Monera, Protista, Fungi, Plantae and Animalia.
• Due to their relatively simpler structure and size, prokaryotes and simple eukaryotes have remained less extensively studied. It has only became possible after the advent of high power microscopes and crystallisation techinques that these organisms ca be studied and debated about.

There are precise conventions to follow while writing a scientific name.

1. The genus name is written first and species should be second.

2. The genus and species names should always be underlined (while writing) or italicised (while printing).

3. The first letter of the genus name is always capitalised and species name never starts with capital letter.

Example: Meleagris or Meleagris,  gallopavo or gallopavo.

Thus, the correct answer is option D.

• Researchers have accepted three levels of biodiversity, namely genetic biodiversity, species biodiversity, and ecosystem biodiversity. All three levels are interrelated.
• Genetic diversity includes variety at the level of genes. It is measured at various levels like population, species, community, and biome.
• Species diversity includes variety in the species. It is the easiest method of studying diversity. Each species has a particular role in the ecosystem.
• Ecosystem diversity includes diversity that deals with species distribution, community patterns, the role of key species and species interactions.