Why do we (and other animals) die? If animals didn't die, they wouldn't need to reproduce (after they had saturated the environment for which they were adapted). If they didn't reproduce and die, their species would not change (evolve). If a species did not change (evolve), it could not adapt to environmental change (or compete with evolving animals). If a species could not adapt to environmental change, it might perish (become extinct), and it could not expand into other environments. Death is, therefore, proof of evolution and a fundamental aspect of biology.
The mode of reproduction in higher animals, sex, affords the opportunity for a wide combination of genes and corresponding traits. This great biodiversity, which augments the influx of new traits via gene mutation, allows a species even more adaptability in response to environmental change. Sex is also, therefore, proof of evolution and a fundamental aspect of biology.
Man is the longest living mammal. Some other mammal life spans follow: 69 years for an Elephant, 50 years for a Horse, 40 years for a Chimpanzee, 20 years for a Cat , 15 years for a Dog, 4 years for a mouse. Some bird life spans are 118 years for a Turkey Buzzard, 102 years for a Swan, 80 years for a Parrot, 55 years for an Eagle, 22 years for a Canary, 8 years for a Humming Bird. For reptiles we find life spans of 152 years for a Giant Tortoise, 123 years for a Box Turtle, 68 years for an Alligator, 28 years for a Cobra. Representative life spans for fish include 60 years for a Catfish, 47 years for a Carp, and 2 years for a Mosquitofish. Insects may have very short life spans; for example, a grasshopper only lives a few months, and a mosquito, two weeks. However, the life expectancy of a queen bee is 6 years.
This natural order and death are due to the fundamental perversion of the universe. But this was caused by the fall of Satan and his angels billions of years ago -- not the fall of 2 humans thousands of years ago.