Reason for diversity in living beings is due to long-term evolutionary changes.

Evolution is the process by which living organisms have developed and diversified over time. It is driven by various factors, including genetic variation and natural selection. The diversity of living beings can be attributed to long-term evolutionary changes, which occur over extended periods.

1. Accumulation of Genetic Variation:
One of the key drivers of diversity in living beings is the accumulation of genetic variation over time. Genetic variation arises through various mechanisms, such as mutations, genetic recombination, and genetic drift. Mutations are random changes in the DNA sequence, which can lead to the introduction of new traits or variations. Over time, these variations can accumulate and give rise to different species or populations with distinct characteristics.

2. Natural Selection:
Natural selection is a fundamental mechanism of evolution that acts on the genetic variation present in a population. It involves the differential survival and reproduction of individuals based on their inherited traits. Individuals with traits that are advantageous in a particular environment are more likely to survive and pass on their genes to the next generation. This process leads to the adaptation of populations to their specific environments and contributes to the diversity of living beings.

3. Speciation:
Long-term evolutionary changes can also result in the formation of new species through a process called speciation. Speciation occurs when a population diverges into two or more distinct populations that can no longer interbreed. This can happen due to various mechanisms, such as geographic isolation, reproductive isolation, or genetic divergence. Speciation plays a crucial role in generating biodiversity as it leads to the development of new species with unique characteristics.

4. Gradual Change:
Long-term evolutionary changes often occur gradually over extended periods. Small changes in traits or genetic composition can accumulate over generations, leading to significant differences between populations or species. This gradual change allows for the accumulation of adaptations and the development of complex organisms with diverse features.

In conclusion, the diversity of living beings is primarily a result of long-term evolutionary changes. These changes involve the accumulation of genetic variation, natural selection, speciation, and gradual change over extended periods. These processes contribute to the vast array of species and traits observed in the natural world.