List of top Behavioural Ecology Questions

The figure illustrates the soil zinc tolerance of the grass species Anthoxanthum along a transect from inside a mine to the middle of a pasture outside the mine.
\includegraphics[width=0.5\linewidth]{62a.png} 
Which one or more of the following processes explain(s) the observed pattern of zinc tolerance in this grass species?

Males of the Indian robin in two populations sing songs of different lengths. Which one or more of the options given is/are an ultimate (not proximate) explanation(s) of the difference in song length between the two populations?
A phylogenetic tree for the evolution of two pigmentation traits in species of fish is shown for clades X, Y, and Z. Genes A and/or B, if mutated, can cause dark pigmentation in the body.
\includegraphics[width=0.5\linewidth]{57a.png}
Which one or more of the following statements is/are correct?
Grey langurs found in the southern Western Ghats (SWG) and grey langurs in Sri Lanka (SL) look very similar. Nilgiri langurs (found in SWG) and purple faced langurs (found in SL) also look similar. If allopatry played a role in the early diversification of this group (at point X in the tree), which one of the phylogenetic trees is most likely to be correct?
\includegraphics[width=0.5\linewidth]{52a.png}
Males of the swordtail fish \textit{Xiphophorus helleri possess long tails, while those of \textit{X. maculatus} do not. Females of \textit{X. helleri} prefer males with longer tails. Interestingly, experimental studies show that females of \textit{X. maculatus} prefer \textit{X. maculatus} males with attached artificial long tails over those without.} If the long-tailed \textit{Xiphophorus species evolved from ancestors that lacked a long tail, which one of the following processes best explains the evolution of the observed preference among \textit{X. maculatus} females?}
Under which one or more of the following conditions can altruism evolve in animal societies?
The figure shows the time-series of atmospheric CO\(_2\) concentration on Earth (graph not-to-scale).
\includegraphics[width=0.5\linewidth]{24.png}
Which one of the factors given is the primary reason for the sudden increase in atmospheric CO\(_2\) concentration after 1950?
The variance in male mating success is \(V_m\) and that of females is \(V_f\). Assuming that the sex ratio is 1:1, in which one of the following mating systems is \(V_m/V_f\) expected to be the greatest?
Which one or more of the following statements about evolution is/are true?
Some air-breathing marine vertebrates such as whales, seals, and marine turtles possess adaptations for long, deep dives. Which one or more of the following is/are examples of such adaptations?
Based on paleontological evidence, eukaryotic organisms are estimated to have first evolved:
Which one of the following is a result of antagonistic coevolution?
Terrestrial plants conduct gas exchange through stomata. Having only few stomata on the leaf surface is a common adaptation to which one of the following conditions?
Which one of the following theories is supported by the distribution patterns of extinct flora such as \textit{Glossopteris across South America, Africa, and Australia, and extant marsupial mammals across South America and Australia?}