Aging is no longer an unsolved problem in biology.

Area of Science:

• Evolutionary Biology
• Gerontology
• Molecular Biology

Background:

• 20th-century research accumulated data on aging without clarifying mechanisms.
• Late 20th-century advancements revealed the biological basis of aging.
• Aging is understood as a trade-off between reproduction and somatic maintenance.

Purpose of the Study:

• To clarify the biological mechanisms underlying aging.
• To explain the variation in aging rates across species.
• To define aging based on current biological understanding.

Main Methods:

• Comparative analysis of aging rates and somatic maintenance efficiency in mammals.
• Review of evidence linking resource allocation to lifespan.
• Synthesis of existing aging theories.

Main Results:

• Aging is defined as the eventual failure of maintenance systems.
• Species with faster reproduction and development exhibit shorter lifespans due to less somatic maintenance.
• Long-lived mammals possess more efficient maintenance mechanisms than short-lived ones.
• Aging is multicausal, involving numerous genes and metabolic resources.
• The evolved design of complex animals is inherently incompatible with indefinite survival.

Conclusions:

• Aging is a multicausal phenomenon, not reducible to a single theory.
• The inherent biological design of organisms limits lifespan.
• Aging cannot be reversed but can be modulated (e.g., by calorie restriction).