anth 2

The Neolithic Period, also known as the New Stone Age, began around 10,000 years ago.
Agriculture began to develop gradually, with roots older than 10,000 years.
The initial process of agriculture was slow and simple:
- Early agricultural practices involved selecting seeds from a few plants based on preference (taste, yield).
- Initial planting was done with no real knowledge of genetics or domestication; it was merely trial and error with preferred traits.

Over time, humans engaged in selective breeding:
- Choosing plants and animals that exhibited desirable traits (e.g., taste, disease resistance, size).
- This selection led to dependent relationships between humans and domesticated species.
Examples:
- Watermelons prior to domestication were very different from those today.
- Corn originally resembled more of a wheat stalk than modern corn.
General traits selected include:
- Increased fleshiness in plants and animals.
- Softer coats on animals.
- Faster growth rates and higher caloric yields.

Domesticated species became fully dependent on humans for survival and reproduction.
Most humans shifted to an agricultural diet, facilitating population growth.

Climate Stability:
- About 10,000 years ago, there was stability in climate after the last Ice Age, crucial for agriculture success.
- Stable climates prevent crop failures, essential for establishing farming practices.
Population Growth:
- Human reproduction rates are higher compared to other primates, prompting the need for a reliable food source as populations expanded.
- Agriculture allowed for denser populations since it produces greater food yields in limited spaces.

Agriculture emerged around the same time in various areas worldwide (12,000 to 8,000 years ago).
Common crops included cereal grains like corn, wheat, and barley.
The concept spread rapidly, leading to significant changes in human population dynamics.

Population estimates before agriculture were approximately 2-3 million.
After adopting agriculture, the population surged to about 300 million and has continued to rise dramatically into the present (8 billion currently).
Agriculture led to faster weaning of infants, affecting birth rates and population dynamics:
- Foragers typically nurse offspring for 2.5 to 3 years, which naturally suppresses ovulation.
- Agriculturalists shifted weaning age to 6-12 months due to the availability of digestible food sources, causing women to bear more children rapidly.

Agricultural diets led to a soft food intake, resulting in:
- Smaller jaw sizes and increased tooth crowding due to decreased chewing stress.
Increased incidents of dental issues:
- Misaligned teeth, cavities due to high carbohydrate intake, and less physical stress from chewing.
Speculation on evolved fewer teeth, particularly wisdom teeth due to selective pressures.
Bone size and strength diminished, leading to decreased overall bone density and strength due to less physical activity and stress.

Higher sedentary lifestyles along with higher population densities contributed to the spread of diseases.
The skeletons from agricultural societies have shown notable evidence of illnesses (increases in TB, syphilis, measles, etc.) that were less prominent in hunter-gatherer populations.
Enamel hypoplasia is common, indicating nutritional stress caused by poor diets.

Agricultural reliance on a few staple crops led to widespread nutrient deficiencies:
- Lack of dietary variety resulted in common issues such as iron deficiency.
- Stressed individuals showed enamel lines, which indicate periods of malnutrition.

Contrary to popular belief, agricultural practices do not ensure complete nutrition:
- Early agricultural diets were deficient in various essential nutrients compared to the diverse diets of hunter-gatherers, leading to starvation risk in crop failures.

Milk consumption varies globally; about one-third of humans can digest milk as adults due to lactase persistence.
Many lose lactase production after infancy, leading to lactose intolerance in adulthood.
Different cultural practices and environments affect the prevalence of lactose tolerance:
- Northern Europeans show higher rates of lactose tolerance due to pastoralism (domestic animal husbandry).
- Pastoralist societies exhibit different adaptations to dairy based on environmental factors and cultural practices (fresh v. fermented dairy).

Lactase persistence mutations (allowing adults to digest lactose) occurred independently in various populations, demonstrating convergent evolution.
Genetics of lactase persistence reflects cultural practices rather than racial hierarchies, emphasizing the complex relationship between genetics and culture.

Agriculture, while enabling population growth and sedentism, has also posed significant health challenges:
- Increased nutritional deficiencies, dental and skeletal issues, and greater susceptibility to diseases.
Modern agriculturalists can maintain healthy lifestyles with access to various nutrients, emphasizing the necessity of awareness regarding nutrition and health in agricultural societies.