List of top Questions asked in GATE Ecology and Evolution

The numbers of rabbits (R) and their predators, foxes (F), in an ecosystem are modelled by the Lotka-Volterra equations as follows: \[ \frac{dR}{dt} = 2R - 0.01 R F \] \[ \frac{dF}{dt} = -F + 0.005 R F \] where the time is measured in months. If there are currently 100 rabbits and 10 foxes, the number of rabbits is changing at the rate of _________ per month and the number of foxes is changing at the rate of ________ foxes per month.

A patch of forest (I) has been declared as a protected area. Conservationists have surveyed three other patches of forest (II, III and IV) and can only recommend one of them for protection. In the figure below, each letter denotes a different species of frog. The conservationists recommend that Patch IV should be protected. Which one of the following metrics is this decision based on?


 

In a deer species that lives in groups, some individuals act as sentinels and are vigilant for predators but there is a trade-off between foraging and vigilance. A researcher collects data on the foraging rates of edge (black) and central (grey) members of the group in two similar forests, one with and one without predators. Which one of the following figures best supports the hypothesis that members at the edge are acting as sentinels in this deer species?


 

Mean global temperature since pre-industrial times has increased approximately by
Which one of the following statements about genetic drift is accurate?
In a grassland (P), there are 8 plant species with a similar number of individuals of each species. In another grassland (Q), there are 12 species with uneven abundances. Which one of the following statements about the Shannon’s diversity index of P and Q is correct?

The table below lists potential environmental conditions in future climates, related to atmospheric carbon dioxide concentrations (CO2) and mean annual temperature (MAT). The table also lists potential outcomes with respect to whether conditions will favour grasses with C3 or C4 photosynthetic pathways. Assuming no other changes in environmental conditions, match the options in the two columns.


 

A researcher wants to estimate the number of crickets in an isolated valley. They captured 56 crickets in the first session, and then marked and released them. In the second session, they captured 41 crickets of which 8 were already marked.
Assuming that there is no birth, death, immigration, or emigration in the cricket population during the study period, what is the estimated number of crickets in this valley? Match the appropriate population estimate with the data given.

The table below provides a list of study questions (P, Q, R) and statistical tests (i, ii, iii).

Which one of the following options correctly matches the study question to the most appropriate statistical test?

Fungus S infects elm trees and fungus T infects chestnut trees, and both kill their hosts within a year of infection. A forest with equal density of elm and chestnut trees is colonized by both pathogenic fungi. A 100 years later, the elm tree population has declined and the chestnut trees have become extinct. Which one of the following mechanisms would NOT contribute to this outcome?

Figure F shows how predation rate changes with increasing prey density.
Which one of the figures represents the per capita death rate of prey under the conditions of F?
 

Many insect species carry the endosymbiotic bacteria Wolbachia, which are maternally inherited. Wolbachia persist over time in these insect hosts by increasing the fitness of the infected host. This increased host fitness can lead to the fixation of Wolbachia in the host population, wherein all individuals carry it. Which one of the following statements describes a process that would NOT allow Wolbachia to become fixed in the host population?
Newts produce tetrodotoxin (TTX), a poison that targets sodium ion channels, for defense against their predators, garter snakes. Several species of garter snakes are resistant to newt TTX due to specific known amino acid substitutions in garter snake sodium channels. Which one of the following is best-suited to identify whether this adaptation in garter snakes has a single origin or multiple independent origins?
The origin and proliferation of which one of the following organisms was responsible for the ‘Great Oxidation Event’?
In a population of 534 blue sheep, there are two alleles, P and Q, at an autosomal locus. Allele P has a frequency of 30%. The number of sheep with the QQ genotype is 262. Assuming that this population is at Hardy-Weinberg equilibrium, the expected percentage of sheep with the PQ genotype in the population is:
In a lake with a large population of fish, there are 4 blue fish for every red fish. Every fish has an equal probability of being caught. If you dip a net into this lake and pick up 4 individuals at random, the probability that you will get 2 fish of each colour is:
Which one or more of the following functions do insects directly perform in ecosystems?
During migration, which one or more of the following do birds use for long-distance navigation?
Fish schools in coral reefs can comprise multiple species that swim and forage together. Which one or more of the following options describe(s) potential fitness benefit(s) to individuals in a mixed-species group?
Mayflies lay eggs in water. Their nymphs (immature life stage) are aquatic and adults are terrestrial. Some mayflies perceive dry, paved parking lots as waterbodies and lay eggs there that do not survive. In this situation, which one or more of these statements is/are correct?

Match the following geographic regions to the mammals that are native to those regions.


 

In this figure, the rectangle (P) depicts the range of temperature and rainfall in which a plant species can survive and propagate. The circle (Q) demarcates the range of temperature and rainfall in which this plant species is actually found. Which one of the following statements about P and Q is accurate for this plant species?


 

Local communities are comprised of a subset of species from the regional species pool. Which one of the following processes is LEAST likely to cause species composition of local communities to differ from one another?
The species richness of trees increases from North to South in the Western Ghats, and from South to North in the Andes. Which one of the following can be an explanation for these patterns?
High water temperatures can cause coral bleaching, which often leads to coral death. In coral reefs that experience repeated bleaching, there can be substantial algal growth on dead coral, eventually leading to an algal dominated ecosystem. Such a transformation is known as