From 8000 to 2000 B.C., adaptations to specialized South American environments accelerate, with sedentary living situations appearing toward the end of the period. Communities along river and sea coasts depend upon the abundant marine resources for food. The greater availability of domesticated plants and animals leads to further sedentism, population growth, and horticulture. Evidence of the presence of belief systems, such as reverence for the dead, appears; such beliefs will continue to be elaborated. The accumulation of valued objects for personal adornment and protection becomes more marked.