Final answer:
Natural selection acts on populations, favoring individuals with advantageous heritable traits under pressures such as competition, leading to adaptations that increase survival and reproduction rates. Both intraspecific and interspecific competition can drive this process of evolution, resulting in adaptations that are beneficial in the specific ecological context.
Step-by-step explanation:
Natural selection acts on populations by selecting for individuals with heritable traits that provide an advantage under certain environmental pressures, such as competition for resources. When a selective pressure like competition is present, individuals who can better obtain resources, avoid predators, or attract mates are more likely to survive and reproduce. This leads to the adaptation of populations over time, as these beneficial traits become more common within the gene pool.
Intraspecific competition within a species intensifies this process, leading to improved adaptations amongst the competitors. Similarly, in interspecific competition, one species may outcompete another for resources, resulting in the better-adapted species having a higher rate of survival and reproduction. Over time, this dynamic can lead to adaptations such as character displacement, where species evolve distinct traits to alleviate competition.
Evolutionary forces like genetic drift and gene flow also play roles in shaping populations, but natural selection is the primary driver of adaptive evolution, ensuring that beneficial traits that allow organisms to better navigate their environment are passed on to subsequent generations.