Final answer:
An organism cannot instantly develop a trait for survival but may acquire adaptations over generations through natural selection, where favorable traits become more common. These adaptations increase an organism's fitness in its specific environment. Shifts in environmental conditions can also change which traits are advantageous.
Step-by-step explanation:
An organism cannot simply develop a new trait out of need or desire to survive in a specific environment. Instead, through the process of natural selection, favorable heritable traits that improve an organism's chance of survival and reproduction tend to become more common over generations. These favorable traits, known as adaptations, help organisms find food, build homes, attract mates, and generally increase their fitness within their environment.
For example, the webbed feet of a platypus are an adaptation for efficient swimming, which is beneficial in its aquatic habitat. Similarly, a cheetah's remarkable speed is an adaptation that allows it to catch prey quickly. Over time, natural selection can lead to the development of new species as those with beneficial traits survive and reproduce at higher rates, passing on those advantageous traits to their offspring. This ongoing process can lead to significant changes in the genetic makeup of a population, refining their adaptations to match their environment.
However, adaptations arise through variations that occur by chance within a population. These variations are then 'selected for' if the traits offer an advantage. For example, a giraffe's long neck allows it to reach leaves high in trees, giving it a survival advantage. This trait becomes more common over time due to natural selection. Conversely, if environmental conditions change, traits that were once advantageous might no longer be beneficial, and natural selection will shift in favor of different traits that offer a survival advantage in the new conditions.