競争

Intraspecific competition occurs between individuals of the same species, while interspecific competition happens between different species. Both types arise when organisms require the same limited resources. Intraspecific competition is common because individuals occupy the same ecological niche and need identical resources. Interspecific competition occurs when species like coyotes and wolves compete for prey or territory in overlapping habitats.

Competitive exclusion occurs when two species compete for the same limiting resource, and one species outcompetes the other over time. The weaker competitor may die out, relocate to a new territory, or evolve to occupy a different ecological niche. This outcome demonstrates how competition shapes species distribution and survival in ecosystems with limited resources.

Direct competition involves organisms interacting to prevent others from accessing resources, such as two male antelopes fighting for a mate or marking territory. Indirect competition occurs when organisms use up shared resources, leaving less available for others, like elephants drinking more water from a pond than other animals. Both reduce overall fitness for competing individuals.

Resource partitioning allows competing species to share limited resources by dividing them spatially or temporally. Caribbean anole lizards exemplify this by residing in different habitat locations and preying on insects entering their preferred territories. This spatial separation effectively divides available food sources, diminishing direct conflicts and competition between different species.

Intraspecific competition serves as a natural mechanism for regulating population size by preventing excessive growth. Stronger individuals outcompete weaker ones for resources, leading to reduced reproduction or death in weaker individuals. This keeps population size in check and prevents crowding and resource depletion within the same species.

Competition is more likely when there is significant overlap between ecological niches. Organisms with similar niches require many of the same resources and compete intensely, while those with very different niches may not compete at all. The degree of niche overlap directly determines whether species will compete and how severe that competition becomes.

Competition provides evolutionary selection pressure both within and between species when resources are limited, forcing organisms to adapt or risk extinction. Individuals better suited to compete survive and reproduce, passing advantageous traits to offspring. Over many generations, this pressure drives niche differentiation and behavioral adaptations that reduce competition intensity.