When death is certain, why did living organisms choose to evolve and die?

Q: When death is certain, why did living organisms choose to evolve and die?

Krishna: 

When organisms come into life, they don’t think about death. Life initially strives to live.

Evolution occurs most of the time to improve living conditions. When those conditions become irrevocably uncertain, death occurs in the end.

Evolution is a natural process that occurs over millions of years, leading to the gradual adaptation of species to their environments. This process is driven by mechanisms such as natural selection, which favours traits that increase the chances of survival and reproduction, and mutation, which introduces new genetic variations.

Over time, these adaptations can result in significant improvements to living conditions. For example, bacteria have developed resistance to antibiotics, and viruses have mutated to evade vaccines, demonstrating how evolution can continuously adapt to new challenges. Additionally, the ability of organisms to evolve, known as evolvability, allows them to adapt to changing environments, further enhancing their survival and reproductive success.

In summary, evolution is a fundamental process that underpins the diversity and adaptability of life on Earth, contributing to the improvement of living conditions through natural selection and the enhancement of evolvability.

However, as years go by things change. The entire biochemistry of an organism changes.

Biological Aging and Cellular Processes:

Cellular Aging: As organisms age, their cells undergo various changes that contribute to the decline in function. One significant factor is telomere shortening, where the protective caps at the ends of chromosomes diminish with each cell division. When telomeres become critically short, cells can no longer divide, leading to a state known as senescence, where they remain metabolically active but do not function properly.

DNA Damage: Over time, cells accumulate DNA damage from environmental factors (like UV radiation) and metabolic processes. While cells have repair mechanisms, these become less effective with age.

Unrepaired DNA damage can lead to cellular dysfunction, contributing to the aging process and eventual death.

Apoptosis: This is a form of programmed cell death that is a normal part of development and tissue regulation. It allows for the removal of damaged or unnecessary cells, but when the balance of cell death and regeneration is disrupted, it can lead to the decline of organ systems and ultimately death.

Evolutionary Perspective

Natural Selection: From an evolutionary standpoint, death plays a crucial role in the survival of species. Organisms that are better adapted to their environments tend to survive and reproduce, while those that are not may die off. This process of change and selection ensures that only the fittest individuals contribute to the next generation.

Resource Allocation: Organisms have finite resources to allocate among growth, maintenance, and reproduction. Effective resource distribution maximizes fitness, meaning that organisms that can manage their resources well are more likely to survive and reproduce, while others may succumb to environmental pressures or internal failures.

In summary, organisms die due to a complex interplay of biological aging, cellular damage, and evolutionary processes. Understanding these mechanisms provides insight into the natural cycle of life and death, highlighting the importance of death in maintaining ecological balance and promoting the evolution of species.

It is easier to create a new organism from scratch than to repair both internal factors such as free radicals, metabolic by-products, etc. and external ones like physical damage, exposure to toxins, and the like.

Underlying causes of death actually can be evolutionary beneficial. For example, shortening of telomeres offers protection against cancer on a cellular level, but also bounds lifespan.

So actually, there may be evolutionary competition (within the same species) of young and old. Mutations helping young but harming older may be preferred to the opposite ones.

Organisms die due to a combination of biological aging, cellular processes, and environmental factors, which ultimately lead to the irreversible cessation of life functions.

There is no evolutionary advantage to dying.

So, your next question should be why organisms die at all? Why hasn't evolution come up with an immortal animal that lives forever?

We have such organisms, for instance, the immortal jellyfish.