List of top Questions asked in GATE EY- 2026

The colour and markings of the eggs of the common cuckoo (Cuculus canorus) are similar to those of the eggs of the great reed warbler (Acrocephalus arundinaceus). Which one or more of the following options explain(s) this similarity?

The genome of a diploid species has 10 genes. In a population of this species, if each gene has two unique alleles, then the number of possible unique genotypes in this population is ______ (Answer in integer)

The values of Stock A and Stock B on a particular day are Rs. 50 and Rs. 80, respectively. An investor invests Rs. 100 in Stock A and Rs. 80 in Stock B. He sells all the stocks the next day when the value of Stock A is Rs. 55 and Stock B is Rs. 70. The profit made by the investor is Rs. ________

Many species of reef fish change sex once during the course of their lives. In these fish, a bigger body size increases an individual's competitive ability. When strong male-male competition creates high variance in fitness among males, which one of the following scenarios is most likely?

Two bacterial variants are growing together in the same flask. At any relative frequency of the two variants, the population growth rate of the rarer variant is higher. This is an example of ________.

Consider a predator encountering two prey types P1 and P2. Assume the energy value of P1 is greater than that of P2. Assume also that the search time to find each prey type is inversely proportional to its abundance in the habitat. The prey-choice model in optimal foraging theory evaluates whether the predator should specialise on P1 or generalise to feed on both P1 and P2. This model predicts specialising on P1 when:
\[ \frac{E_1}{S_1+h_1} > \frac{E_2}{h_2} \]
where \(E_1\) is the energy value of P1; \(h_1\) is handling time for P1; \(E_2\) is the energy value of P2; \(h_2\) is handling time for P2; \(S_1\) is the search time for P1. According to the condition given above, which one or more of the following options does the decision to specialise on P1 depend on?

A black square PQRS has been cut into two parts. One part of it is shown in Panel I. Which one of the shapes labelled (i), (ii), (iii), and (iv) in Panel II is the other part of the same square?

Which one or more of the following benefits can explain the evolution of dispersal of animals from their natal area?

Two species of butterflies are equally toxic to their main potential predator. Their morphological similarity helps to reduce predation rates on both species. This phenomenon is known as _________.

Ecologists have studied the distributions of birds on archipelagos. Some studies found an interesting "checkerboard" pattern within island groups. Sister species were never present on the same island, even when the islands were very close to each other. Which one of the following processes best explains this checkerboard pattern?

Students M and N sampled body lengths of two populations of a fish species using the same study design. The table below summarizes their data as mean \(\pm\) standard error.

Body length (cm)	Population I	Population II
Student M	\(8.0 \pm 1.2\)	\(6.2 \pm 0.7\)
Student N	\(10.0 \pm 0.6\)	\(5.1 \pm 0.3\)

Given that the data are normally distributed, when comparing the means of the populations using a t-test, which student will find a lower p-value?

Species 1 and 2 belong to the same genus and co-occur at the same site. Which one or more of the following strategies would facilitate their coexistence at the site?

Consider the analogy:
Water : P :: Food : Q
Choose the combination of P and Q from the options below that forms a meaningful analogy.

Which one or more of the following phenomena make(s) small populations vulnerable to extinction?

The scatter plot below shows annual rainfall (in mm) on the x axis and the number of plant species recorded at a site on the y axis. Each point is one location, and the points trace out a clear increasing pattern that looks close to a straight line as rainfall rises.

Based on the pattern in the graph, which one of the following statistical methods would be most appropriate to model the relationship between annual rainfall and the number of plant species?

Two isolated populations M and N have population sizes of \(100\) and \(1000\) individuals, respectively. The starting allele frequencies \(p\) and \(q\) are \(0.5\) in both populations. Assuming no selection, which one of the following is expected after \(100\) generations?

The Biological Species Concept was proposed by _________.

Many species in mountain ranges are shifting their ranges to higher, cooler elevations in response to warming temperatures because of climate change.

The graph above shows how the midpoint of elevational range in the year 2025 is related to the midpoint of the elevational range in the year 2000 for species in temperate (open circle) and tropical (solid circle) mountain ranges. Each point represents a species, and the dashed line is the 1:1 or the identity line (with intercept = 0 and slope = 1). Which one of the following statements is consistent with the above graph?

A flask containing nutrient-rich media is seeded with 100 isogenic bacteria. Assuming that no bacteria die in the flask, after approximately how many generations will the population reach a size of \(10^5\)?

Which one or more of the following diseases is/are zoonotic?

Species that co-occur in space and time tend to be similar to each other in traits such as tolerance to heat or to drought. This is most likely because of _________.

Which one of the following statements is true for most ants and bees?

The distributions of beak size in a bird population at two different times, \(t=0\) and \(t=t_1\), are shown below. At \(t=0\) beak sizes form a single narrow peak centred around 5 mm. By \(t=t_1\) the distribution has split into two separate peaks, one smaller and one larger than 5 mm, with very few birds still having a beak size close to 5 mm.

In going from time \(t=0\) to \(t=t_1\), the variance of the distribution in beak size in the population has _________.

Figures (i) and (ii) below represent intercity highway systems, where each black dot is a city and each line segment joining two dots is a direct highway between those two cities. Figure (i) is a 4 by 4 grid of cities connected only along the horizontal and vertical grid lines, with no diagonal roads. Figure (ii) has 5 cities joined by 6 highways in an irregular network with one extra interior city.

A salesperson needs to make a trip. She needs to start from a city, visit each of the remaining cities exactly once, and finally return to the same city from which she started. Which one of the following options is then true?

A day can only be cloudy or sunny. The probability of a day being cloudy is 0.5, independent of the condition on other days. What is the probability that in any given four days, there will be three cloudy days and one sunny day?