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Biology · 2026 · 2 marks
Principles of Inheritance and VariationMendel’s Laws of Inheritance2 marksUnderstandvery short answer
CBSE 2026 · Region 1 · Set 3 · Q20
(a) Mendel published his work on inheritance in 1865, but it remained unnoticed for over three decades. State the reasons why his work was not…
(a)
Mendel published his work on inheritance in $\displaystyle 1865$, but it remained unnoticed for over three decades. State the reasons why his work was not recognised during his life time. ($\displaystyle 4$ points)
OR
(b)
What is adaptive radiation ? Give one example from any habitat. $\displaystyle 1$+$\displaystyle 1$
Marking-scheme solution
-Communication was not easy at that time.
-Concept of genes as stable and discrete units that controlled the expression of traits and of the pair of alleles which did not blend with each other was not accepted by his contemporaries.
-Using mathematics to explain biological phenomenon was new and unacceptable.
-Mendel could not provide any physical proof for the existence of factors or what they are made of.
Adaptive radiation -The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography.
Example – Darwin’s finches in Galapagos islands. From original seed eating birds other forms arose with altered beaks enabling them to become insectivorous and vegetarian/ A number of marsupials each different from the other evolved from an ancestral stock but all within the Australian island continent / or any other example
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