Ecological Niche

While habitat answers 'where does it live', ecological niche answers 'what does it do there' — the total functional role an organism plays in its community, combined with the sum of all the environmental conditions and resources it requires. Species that share broadly similar roles and niche dimensions within a community are grouped as a 'guild', while species occupying an equivalent niche in different, unconnected geographic regions are called 'ecological equivalents'. Niche differences let closely related species coexist peacefully in the very same habitat: crickets and grasshoppers both live in the same field, yet the grasshopper is diurnal, active in daylight and feeding openly on plant parts, while the cricket is nocturnal, hiding under leaf litter by day and becoming active only at night — so the two never actually compete for the same resources at the same time. A similar partitioning shows up among fish s …