Evolution is a gradual process that occurs over long periods of time, typically taking millions of years for significant changes to accumulate. The misconception that animals should change into entirely different animals right away stems from a misunderstanding of how evolution works.
Evolution is driven by the mechanisms of variation, inheritance, and natural selection. Genetic variations occur randomly within populations through processes like mutation and recombination. If a particular variation provides individuals with a survival or reproductive advantage in their environment, it is more likely to be passed on to future generations. Over time, these accumulated changes can lead to the formation of new species.
However, it's important to note that evolution does not occur in a linear fashion with one species instantaneously transforming into another. Instead, it involves a branching pattern of gradual change, resulting in the emergence of new species from common ancestors. The process is often compared to a tree, with different species representing the branches that have diverged over time.
The vast timescales and complex processes involved in evolution make it difficult to observe significant changes within a human lifetime. However, extensive evidence from various scientific disciplines, such as paleontology, genetics, and comparative anatomy, supports the theory of evolution and demonstrates how species have changed over millions of years.
It's also worth noting that not all species undergo the same rate or extent of evolutionary change. Some species may remain relatively stable for long periods, while others may undergo more rapid changes due to environmental pressures or other factors. Evolution is a diverse and ongoing process, constantly shaping the diversity of life on Earth.