Practice question

Living in a group can lower each antelope's probability of being killed through several mechanisms. More individuals can detect predators earlier, coordinated escape can confuse an attacker, and the dilution effect spreads a given attack risk across many potential targets. Individuals near the center may also reduce their exposure through selfish-herd positioning. A larger aggregation may be easier for predators to notice, so grouping does not necessarily reduce predator attraction, yet per capita mortality can still decline once an attack occurs. The benefit concerns individual risk rather than birth rate or general energy expenditure, both of which may vary independently with group size. At population level, this mechanism can influence abundance, coexistence, and evolutionary selection. Separating immediate individual effects from longer-term community outcomes gives the selected concept a clearer ecological meaning and avoids relying only on memorized terminology. The relevant evidence concerns process rather than wording alone. Linking the described pattern to energetic returns, fitness consequences, or receiver responses makes the inference biologically coherent and distinguishes it from the competing alternatives.