The question asks for the definition of clinal variation in population biology.
Clinal Variation: Geographic Trait Continuum
Clinal variation describes a gradual change in the features of organisms of the same species over a geographic area. This change is often seen in a specific genetic trait.
The key aspect is the geographic continuum, meaning the trait doesn't change abruptly but instead shows a smooth, progressive shift from one population to another across distances. This pattern often reflects adaptation to changing environmental conditions along the geographic range.
Analyzing Other Options
- Variation among breeding isolates refers to genetic divergence between separated populations, not a gradual continuum.
- Variation due to genetic drift involves random changes in allele frequencies, which can cause variation but doesn't inherently describe a geographic continuum pattern.
- Variation due to migration can contribute to or alter clinal patterns, but migration itself isn't the definition of clinal variation. Clinal variation is the observed pattern of gradual change.
Therefore, the most accurate definition highlights the geographic continuum of a genetic trait.
Important Questions from Evolutionary Mechanisms
The frequency of homozygotes in a diploid population is 0.68. Assuming that the population is in Hardy-Weinberg equilibrium, the frequencies of the two alleles are
Convergent evolution creates:
Given below are the possible reasons of high probability for extinction of species:
(i) Increased homozygosity of alleles
(ii) Increased heterozygosity of alleles
(iii) Decreasing population sizes
(iv) Increasing demographic stochasticity
(v) Decreasing environmental stochasticity
Which one of the following options represents the correct combination of reasons that can lead to the highest probability of extinction of species?
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?
According to Hamilton's rule, 'r' is the coefficient of relatedness between two interacting individuals, 'B' is the benefit to thr recipient and 'C' is the cost to the donor. Which of the following relationships will result in an altruistic behaviour?
