CBSE 2024 · Region 5 · Set 1 · Q28 · 3 marks
The world is facing accelerated rates of species extinction largely due to human activities. Explain any three human activities responsible for accelerated rates of species extinction.
Marking-scheme solution
Habitat loss and fragmentation, - degradation of habitat such as cutting and
clearing of (Amazon rain) forest for developing cultivable land leads to the fragmentation of habitat will affect the population of organisms living in that area / any other correct explanation
Overexploitation of natural resources, - Steller’s Sea cow or passenger pigeon
or marine fish / any other correct explanation
Alien species invasion, - Nile perch introduced in lake Victoria in east Africa
lead eventually to the extinction of $\displaystyle 200$ species of Cichlid fish or introduction of Clarias gariepinus ( African catfish) for aquaculture purposes is posing a threat to indigenous catfishes or Parthenium ( carrot grass) or Lantana or
Eicchornia (water hyacinth) introduced unintentionally causing decline of indigenous species /
Co-extinctions of species, - extinction of any organism or plant or animal or
plant-pollinator mutualism or fish-parasite relationship will lead to extinction of other (obligatory) species
Degradation of habitat by pollution, - threaten the survival of many species /
mammals / (migratory) birds.
The colonization of (Tropical pacific) islands by humans, led to extinction of
(more than $\displaystyle 2000$ species) native birds.Biodiversity and ConservationBiodiversity ConservationUnderstandshort_answermedium
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CBSE Class 12 Biology past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.