The following statements were made about adaptive radiation: A. Adaptive radiation is a kind of divergent evolution driven by ecological diversification. B. Adaptive radiation is the divergence of unrelated taxa into different niches. C. Adaptive radiation is rare on archipelagos removed from the mainland. D. Processes unrelated to niche exploitation can be major drivers of species diversification Choose the option that represents all correct statements.
A and D
Adaptive Radiation Explained
Let's analyze each statement about adaptive radiation to determine which ones are correct.
Statement A: Adaptive radiation is a kind of divergent evolution driven by ecological diversification.
Adaptive radiation is indeed a classic example of divergent evolution. It occurs when a single lineage rapidly diversifies into multiple species that occupy different ecological niches. This diversification is driven by the exploitation of different resources or habitats, which is ecological diversification. This statement is consistent with the definition of adaptive radiation.
Statement B: Adaptive radiation is the divergence of unrelated taxa into different niches.
This statement is incorrect. Adaptive radiation involves the divergence of species from a single ancestral lineage or a group of closely related taxa, not unrelated ones. The divergence of unrelated taxa into similar niches is known as convergent evolution.
Statement C: Adaptive radiation is rare on archipelagos removed from the mainland.
This statement is incorrect. Archipelagos (island chains) are often considered prime locations for adaptive radiation. Their isolation from the mainland and the availability of new, unoccupied ecological niches provide fertile ground for immigrant species to diversify rapidly. Famous examples include Darwin's finches on the Galapagos Islands and the Hawaiian honeycreepers on the Hawaiian Islands.
Statement D: Processes unrelated to niche exploitation can be major drivers of species diversification.
While adaptive radiation is specifically linked to niche exploitation, species diversification in general can be driven by various other factors. These can include geographic isolation without immediate niche differences (allopatric speciation), sexual selection, genetic drift, polyploidy, and mutations. Therefore, processes not directly related to exploiting different ecological niches can certainly lead to the formation of new species. This statement is correct in the broader context of species diversification.
Based on the analysis, statements A and D are correct, while statements B and C are incorrect.
We are looking for the option that represents all correct statements. The correct statements are A and D.
Important Questions from Evolution and Behavior
Reduction in the frequency of heterozygous genotype with a concomitant increase in the frequency of homozygous genotype, in context of random mating is due to
A founder population has an Aa heterozygous genotype with a frequency of 1, and no individual with either AA or aa genotypes. With repeated self-fertilization, the frequency of AA, Aa and aa after three generations will be:
Many species of birds call at dawn in temperate regions. The phenomenon is referred to as "Dawn Chorus". Several explanations have been proposed for this. Which one of the options is NOT a correct explanation for the occurrence of "Dawn Chorus"?
- Column X lists evolutionary ideas and scientists who proposed them, and Column Y lists the description of these ideas.
Column X
Column Y
A.
Modern synthesis by Julian Huxley
I.
A stochastic process where lineages show random geneological relationships when traced back in time.
B.
Phyletic gradualism by Charles Darwin
II.
Evolutionary change appears instantaneous between geological sedimentary layers.
C.
Punctuated equilibrium by Stephen Jay Gould and Niles Eldredge
III.
Synthesis between Mendelian genetics, population genetics, and selection theory.
D.
Coalescent model (inspired by) Wright- Fisher model
IV.
New species arise by the gradual transformation of ancestral species.
Which one of the following options represents all correct matches between Column X and Column Y? Which one of the following statements about the molecular clock hypothesis as proposed by Zuckerkandl and Pauling 1962 is CORRECT?
