Organisms and Populations

Desert ants are known to use landmarks (reference points), pedometers (memorising step counts), and optic flow (rate of passing objects across its eye to estimate navigation speed) to navigate across deserts. A desert…

The fundamental niche of a species is the full range of environmental conditions and resources a species can potentially occupy in the absence of limitations. The realized niche is the actual, smaller subset of the…

Three different bacterial strains (P, Q, and R) when grown independently in a culture medium showed typical growth curves. Equal number of cells from all three actively growing cultures are mixed and grown together for…

The population sizes of two organisms P and Q growing in a given habitat is shown. If P and Q share ecological relationship, then they most likely represent

Clutch size in birds refers to the number of eggs laid in a single nesting attempt by a nesting pair of birds while number in brood refers to the number of young hatched. The graphs below represent the relationship…

In a nutrient-poor habitat under study, it was observed that pine trees depend on mycorrhizal fungi associated with the root system for nutrient acquisition from the soil. The mycorrhizae in turn depend on the pine…

In order to study the effect of external cues on circadian rhythm, the spontaneous wheel-running activity of flying squirrels in total darkness was recorded over 24 hours for several days. The results are shown below.…

On an oceanic island, long isolated away from any continent, there are only four co-existing species: flowering shrub, rabbit, large deer and small fox. The food web for the island ecosystem is depicted below. Deer and…

Given is a diagram representing the annual mean temperature and the annual mean precipitation in three biomes $\mathbf{P}, \mathbf{Q}$ and $\mathbf{R}$ on the planet. All the animals living in these biomes together can…

The Russian scientist G. F. Gause carried out experiments on three species of Paramecium by growing each species separately in identical culture conditions (Experiments 1, 2 and 3) as well as in combination of two…

Ecologist David Tilman grew laboratory populations of two species of diatoms namely Asterionella formosa (Af) and Symedra ulna (Su) in liquid media supplemented with silica. The researcher monitored not only the…

The larvae (caterpillars) of a species of insect that feed on leaves of a tree were used in this investigation. The larvae were fed for 30 days on either green leaves or yellow leaves. The bar-diagram below shows the…