Domestication
The Latin word domesticus means belonging to the house. This term remained loosely defined until the 21st century when American archaeologist Melinda A. Zeder provided a clear description. She described it as a long-term relationship where humans take control and care of another organism for predictable resources. Her definition distinguishes this process from taming an individual animal. Taming affects only one creature while domestication changes entire species over generations. Michael D. Purugganan proposed a broader coevolutionary process involving niche construction. He noted that insects like termites have also domesticated fungi species. This adds complexity to how we understand mutual benefits between species. Domestication creates obligate synanthropes that cannot survive outside human environments. These populations exist as sink populations with death rates higher than birth rates in the wild.
Dogs became the first animals domesticated by humans at least 15,000 years ago. They served as commensals adapting to human niches before agriculture existed. Goats, sheep, and cows followed around 11,000 years ago in the Near East. Rice was first cultivated in China some 9,000 years ago. The horse came under domestication around 5,500 years ago in central Asia as working animals. Silkworms and western honey bees were domesticated over 5,000 years ago for silk and honey respectively. Small-scale trial cultivation of cereals began some 28,000 years ago at Ohalo II site in Israel. Neolithic societies in West Asia began cultivating plants around 13,000 to 11,000 years ago. Indigenous peoples in the Americas started growing peanuts, squash, maize, potatoes, cotton, and cassava beginning around 10,000 years ago. Agriculture developed in approximately 13 centers around the world. Each region domesticated different crops and animals independently. Two thousand years after initial livestock domestication, humped zebu cattle appeared in Baluchistan Pakistan.
Charles Darwin recognized small numbers of traits making domestic species distinct from wild ancestors in his 1868 book. He identified conscious selective breeding alongside unconscious selection by natural processes. Domesticated mammals tend to be smaller and less aggressive than their wild counterparts. Common traits include floppy ears, smaller brains, and shorter muzzles known as domestication syndrome. These changes affect genes controlling behavior in animals while plant changes impact morphology and physiology. Wild wheat shatters and falls to ground when ripe but domesticated wheat stays on stem for easier harvesting. This mutation occurred randomly in wild populations before early farmers selected it repeatedly. Domesticated plants often lack seed dormancy and have reduced or no vernalization requirements. They show increased grain size and altered color, taste, and texture compared to wild relatives. Population bottlenecks create situations similar to founder effects where most strains born from few ancestors.
Three major pathways led mammal domesticates into domestication according to archaeological evidence. Commensals adapted to human niches included dogs, cats, and possibly pigs. Prey animals sought for food encompassed sheep, goats, cattle, water buffalo, yak, pig, reindeer, llama, and alpaca. Animals targeted for draft and riding included horses, donkeys, and camels. Humans did not intend to domesticate mammals from commensal or prey pathways initially. Their role in survival and reproduction gradually led to formalized animal husbandry over longer time frames. Directed pathways for draft and riding proceeded from capture to taming differently than other routes. Archaeological records suggest these processes took place over much longer periods than expected. Long-term bidirectional gene flow between wild and domestic stocks was common in donkeys, horses, camelids, goats, sheep, and pigs. Human selection for domestic traits likely counteracted homogenizing effects of gene flow from wild boars into pigs. The 2023 parasite-mediated hypothesis suggests endoparasites could have mediated mammal domestication through modifying endocrine activity.
Wild wheat shatters and falls to ground when ripe but domesticated wheat stays on stem for easier harvesting. This change occurred because a random mutation existed in wild populations at beginning of cultivation. Farmers harvested wheat with this mutation more frequently making it seed for next crop without realizing intent. Domesticated plants differ from wild relatives through lack of shattering and loss of fruit abscission. They show less efficient breeding systems requiring human intervention for pollination. Larger seeds with lower success in the wild characterize many crops alongside sterility examples like seedless fruits. Edible parts became larger including cereal grains or fruits while becoming more easily separated from non-edible portions. Increased number of fruits or grains appears alongside altered color, taste, and texture changes. Daylength independence and determinate growth patterns emerged during domestication processes. Repeated hybridization and polyploidy enabled rapid evolutionary responses to artificial selection in wheat genomes. Polyploidy increases chromosome numbers bringing new combinations of genes enabling further changes by chromosomal crossover.
Selection of animals for visible traits produced undesired consequences for domestic animal genetics. Zoonotic diseases emerged as side effects including viral poxes, measles, tuberculosis from cattle. Pigs and ducks contributed influenza while horses brought rhinoviruses to human populations. Many parasites originated in domestic animals alongside denser human populations providing conditions for pathogen reproduction. Mutations can be fixed in populations by selective sweeps increasing mutational load when reproductive fitness controlled by management. Population bottlenecks created situations where most strains born from few ancestors lost much genetic variation. Domesticated ecosystems provide food but resulted in habitat alteration or loss and multiple extinctions commencing in Late Pleistocene. Anarcho-primitivism critiques domestication destroying primitive harmony with nature replacing it with social hierarchy. Sociologist David Nibert argues domestication involved violence against animals damaging environment corrupting human ethics. This paved way for conquest, extermination, displacement, repression, coerced servitude, gender subordination, sexual exploitation, and hunger. Industrialized agriculture on land with simplified ecosystems continues reducing predator and natural dangers promoting commerce.
At least three groups of insects have independently domesticated species of fungi they feed upon. Ambrosia beetles excavate tunnels in dead trees introducing fungal gardens as sole nutrition source. Symbiotic fungi produce ethanol attracting beetles preventing growth of antagonistic pathogens selecting beneficial symbionts. Leafcutter ants carry leaf discs back to nests feeding material to tended fungi over 30 million years. Some fungi farmed by Mycocepurus smithii constantly produce spores useless to ants eating hyphae instead. Fungus-growing termites cultivate Termitomyces fungi to eat exactly once between 25, 40 million years ago. Roger Heim described these fungi growing on combs formed from termite excreta dominated by tough woody fragments. The relationship represents fully obligate symbiosis existing on both sides for approximately 330 species. These systems demonstrate non-human domestication through complex mutual dependencies requiring specialized behaviors and environments.
Continue Browsing
Common questions
What is the definition of domestication provided by Melinda A. Zeder?
Melinda A. Zeder defined domestication as a long-term relationship where humans take control and care of another organism for predictable resources. This process distinguishes itself from taming an individual animal because it changes entire species over generations.
When did dogs become the first animals domesticated by humans?
Dogs became the first animals domesticated by humans at least 15,000 years ago. They served as commensals adapting to human niches before agriculture existed in the Near East around 11,000 years ago when goats, sheep, and cows followed.
How many centers developed agriculture independently across the world?
Agriculture developed in approximately 13 centers around the world with each region domesticating different crops and animals independently. Neolithic societies in West Asia began cultivating plants around 13,000 to 11,000 years ago while Indigenous peoples in the Americas started growing peanuts, squash, maize, potatoes, cotton, and cassava beginning around 10,000 years ago.
What are common traits associated with domestication syndrome in mammals?
Common traits include floppy ears, smaller brains, and shorter muzzles known as domestication syndrome. These changes affect genes controlling behavior in animals while wild counterparts tend to be larger and more aggressive than their domesticated forms.
Which insects have independently domesticated species of fungi they feed upon?
At least three groups of insects including Ambrosia beetles, leafcutter ants, and fungus-growing termites have independently domesticated species of fungi they feed upon. Fungus-growing termites cultivate Termitomyces fungi to eat exactly once between 25, 40 million years ago.