Speciation: The Natural Formation of New Species
Speciation is a fundamental concept in evolutionary biology. It refers to the evolutionary process by which new biological species arise.
Understanding Speciation
The core idea behind speciation is the splitting of an existing species population into two or more distinct populations that are reproductively isolated from each other. This means they can no longer interbreed successfully.
Key Aspects of Speciation:
- Natural Process: Speciation occurs naturally over time due to various evolutionary mechanisms like genetic drift, mutation, and natural selection, often driven by geographic or reproductive isolation.
- Formation of New Species: It results in the emergence of new, distinct species from a common ancestral species.
- Reproductive Isolation: This is a crucial factor where populations diverge to a point where gene flow between them ceases.
Analysis of Options:
- Option 1 & 2 (Extinction): These options describe extinction, which is the opposite of speciation (species dying out, not forming).
- Option 4 (Characterisation): This involves identifying and describing species based on their traits, not the process of their formation.
- Option 3 (Splitting Naturally): This accurately describes speciation – one species dividing into two or more new species through natural evolutionary processes.
Therefore, the definition aligning with the biological process of speciation is the natural splitting of one species into two or more.
Important Questions from Evolutionary Mechanisms
Given below are proposed analogous structures among organisms.
A. wings of birds and bats
B. wings of bats and tetrapod digits
C. tendrils of Vitis and tendrils of pumpkin
D. tubers of potatoes and sweet potatoes
E. fins of fish and flippers of a whale
Which one of the following options correctly states the analogous structures?
Biased gene conversion (BGC) has been proposed to cause changes in allele frequencies in a population. Select the statement that is NOT correct about BGC.
- Long - term patterns of evolution are shaped by large scale process(s) such as :
(I) Speciation
(II) Mass extinction
(III) Adaptive radiation
Choose the correct answer: Match List I with List II
List I (Term) List II (Definition) A. Sympatric
speciationI. The process by which organisms adapt to changed environmental conditions to form new species in
a relatively short period.B. Parapatric
speciationII. The process of differentiation and acquiring reproductive isolation within the same geographical
area.C. Adaptive
radiationIII. Population evolving in different geographical regions due to isolation. D. Allopatric
speciationIV. The process of speciation which occurs between adjacent populations within a broadly continuous
habitat.
Choose the correct answer from the options given below:Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Theoretically, natural selection moulds and shapes populations through differential fertility and mortality.
Reason R: Sickle cell provides a persuasive argument for differential mortality, affecting populations in malarial environment, but evidence for differential fertility is far from unequivocal.
In the light of the above statements, choose the most appropriate answer from the options given below
