Q1
A sudden, random change in allele frequency in a small population due to chance events is called:
📝 SolutionGenetic drift is a random change in allele frequencies, especially significant in small populations, and is not driven by natural selection.
Q2
Darwin's finches on the Galapagos Islands, which evolved different beak shapes from a common ancestor to exploit different food sources, are a classic example of:
📝 SolutionAdaptive radiation is the diversification of an ancestral species into many new forms adapted to different niches, as seen in Darwin's finches evolving varied beak shapes.
Q3
In the broad sequence of human evolution, which of these hominids is generally placed closest to modern humans?
📝 SolutionHomo sapiens (represented by fossils like Cro-Magnon man) represents modern humans, the most recent stage in the broadly accepted human evolutionary lineage.
Q4
Assertion (A): Variation is essential for the process of natural selection.
Reason (R): Without heritable variation among individuals, there would be no differences for natural selection to act upon.
Choose the correct option:
Reason (R): Without heritable variation among individuals, there would be no differences for natural selection to act upon.
Choose the correct option:
📝 SolutionNatural selection works by favouring individuals with advantageous heritable traits; if all individuals were identical, there would be nothing for selection to differentiate or act upon. R correctly explains A.
Q5
Assertion (A): The forelimbs of a whale, a bat and a human are homologous organs.
Reason (R): Despite performing very different functions (swimming, flying, grasping), they share the same basic pentadactyl limb structure derived from a common ancestor.
Choose the correct option:
Reason (R): Despite performing very different functions (swimming, flying, grasping), they share the same basic pentadactyl limb structure derived from a common ancestor.
Choose the correct option:
📝 SolutionHomology is based on shared structural/anatomical origin, not function. The pentadactyl limb pattern common to whale, bat and human forelimbs, inherited from a shared ancestor, makes them homologous despite their varied functions. R correctly explains A.
🔔 Don't miss tomorrow's DPP!
Get a new DPP every morning, straight to WhatsApp — free.
📱 Get DPP on WhatsApp
Class 12 · Biology
Fully prepared for the board exam?
Check out Alpha Classes' Exam Kits — notes, PYQs, mock tests and much more.
View Exam Kits →