What is meant by the term speciation ? List four factors which could lead to speciation.
What is meant by the term speciation ? List four factors which could lead to speciation.
Official answer
Speciation is the evolutionary process by which new, distinct biological species arise from pre-existing populations.
Four factors that could lead to speciation are:
- Geographical Isolation: Physical barriers (such as mountains, rivers, or oceans) separate a population, preventing gene flow between the sub-populations.
- Genetic Drift: Random changes in allele frequencies in small, isolated populations over generations.
- Natural Selection: Different environmental conditions select different advantageous variations in isolated populations, leading to evolutionary divergence.
- Genetic Mutation / Variation: Accumulation of DNA changes over time that leads to reproductive isolation, making the two groups unable to interbreed.
Marking scheme
- 1.Defining speciation as the formation of new species from existing ones. (1 mark)
- 2.Listing any four factors (0.5 marks for each correct factor). (2 marks)
Hint
Think about how a single species of organisms can split into two different groups that can no longer interbreed.
Quick oral answer
Speciation is the formation of new species from existing ones. Four factors leading to it are geographical isolation, genetic drift, natural selection, and genetic mutations.
Common mistakes
- 1.Confusing speciation with simple variation within a single species.
- 2.Forgetting that geographical isolation must lead to reproductive isolation for speciation to occur.
Analysis and explanation
Speciation occurs when populations of a species become reproductively isolated and diverge genetically. Geographical isolation acts as a physical barrier that stops interbreeding (gene flow). Over time, genetic drift (random fluctuations) and natural selection (adaptation to local environments) operate independently on these isolated groups. Combined with mutations, these processes lead to significant genetic differences, eventually preventing successful reproduction even if the populations meet again.
Interesting facts
The famous Darwin's finches on the Galápagos Islands are a classic example of speciation, where a single ancestral species diverged into multiple species with different beak shapes adapted to different food sources.
Question details
Q18 of 41 questions
- Board
- CBSE
- Class
- Class 10
- Subject
- Science
- Year
- 2012
- Section
- Section A
- Marks
- 3
- Type
- Short Answer
- Chapter
- Heredity
- Topic
- Speciation
- Bloom's level
- Remembering
- Syllabus topic
- Speciation
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Frequently asked questions
How many marks does this question carry in CBSE Class 10 Science 2012?
This question carries 3 marks in the CBSE Class 10 Science 2012 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Heredity" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Speciation" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2012 paper?
This is a Short Answer question from Section A in the CBSE Class 10 Science 2012 paper.