Human teeth got smaller primarily because of advancements in food processing and preparation techniques.
Factors Contributing to Tooth Size Reduction
Over the past 2.5 to 5 million years, hominin jaws and teeth have demonstrably reduced in size. This is largely attributed to the following:
- Improved Tools and Techniques:
- Cutting tools: Early hominins developed sharper and more efficient tools for cutting food into smaller, more manageable pieces. This reduced the need for large teeth to tear through tough materials.
- Pounding and Grinding Tools: The use of tools for pounding and grinding food made it easier to break down fibrous plants and tough meats. This pre-processing reduced the workload on teeth.
- The Use of Fire for Cooking:
- Softening Food: Cooking with fire softens food, making it easier to chew and digest. This reduced the selective pressure favoring larger, more robust teeth.
- Nutrient Availability: Cooking also increases the bioavailability of nutrients in food, reducing the need to consume large quantities of raw materials.
Impact on Jaws
The reduction in tooth size is directly linked to a corresponding reduction in the size of hominin jaws. Smaller teeth require smaller jaws to support them, leading to a more gracile facial structure over time.
Summary
In summary, the combination of advanced food processing techniques using tools and the introduction of cooking with fire resulted in a decreased need for large, powerful teeth, ultimately leading to their reduction in size over millions of years of hominin evolution.
