Final answer:
Survival and reproduction among Darwin's finches are influenced by their inherited traits and the environment, not random events. Variations that provide an advantage, such as beak size adapted to available food sources, are selected for, demonstrating natural selection at work.
Step-by-step explanation:
The question pertains to Darwin's postulate on natural selection and the finches in the Galápagos Islands as a famous example. Darwin observed that survival and reproduction are influenced by the variations that provide an advantage in a given environment.
For example, Darwin's finches exhibited varied beak sizes that were inherited and could change over time in response to the availability of different-sized seeds, a critical food resource. Thus, survival and reproduction are not completely random events but are affected by natural selection.
Through studies like those conducted by Peter and Rosemary Grant, we see that during periods of selective pressure, such as changes in food availability, those individuals with beak shapes better suited to the available food source were more likely to survive and reproduce.
In essence, their beak size allowed them to adapt to changes in their environment more successfully than others, leading to a greater representation of these traits in subsequent generations.
In conclusion, reflecting on Darwin's postulates, survival and reproduction among organisms, including Darwin's finches, is influenced by their inherited traits and the selective pressures of their environment, meaning that the most fit individuals are more likely to pass on their genes.