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Domestication! Definitions: Domestication? Domestic Animal? Feralization? |
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Definition
Domestication (definition): that process by which a population of animals becomes adapted to humans and a captive environment by a combination of genetic change and developmental changes that reoccur each generation.
The purpose of domestication has been for food, fiber, beasts of burden, companions and assistants. Recently, domestication has included animals for scientific research, entertainment and rescue from extinction.
A Domestic Animal is one that is bred in captivity for purposes of economic profit to a human community that maintains mastery over breeding, territory and food supply.
Feralization is the process of 'domestication in reverse'; animals escaping from domestication and returning to their wild state (feral pigs in CA, feral horses in Nevada) |
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Domestication! Definition of Symbiosis (3 parts) |
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Definition
Symbiosis is the well known situation in biology when 2 different species interact to the benefit of both.
a) preadaptations to domestication:
hierarchical, nonterritorial group structure, low space requirement, polygamous mating, female accepts other young, precocious young, readily tamed, omnivorous, short flight distance, habituate to humans, adaptable to many environments
b) genetic change can occur through inbreeding, random change (drift), artificial selection, natural selection
c) environmental changes that accompany domestication include: food & water are provided, lack of predation, climate moderation, reduction in quality & quantity of space, forced social groupings, frequent interaction with humans, routinely applied management practices |
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When and where? How many years ago? What is developed in: Near East? China? Tehuacan Valley? Northern Syria? |
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Definition
2) When & Where of Domestication - an unusual, impossible question to answer exactly, but domestication originated almost simultaneously around the world after the end of the Pleistocene (an approx. 1 million year epoch with glaciers as far south as St. Louis, covering 1/3 of Earth's landmass).
First signs - 9,000 yrs BP (Before Present) in Near East, Far East, Meso-America and Peru; Domesticated cereal grains in the mideast (9,000 BP), domesticated Maize in Tehuacan Valley, Mexico (7,000 yrs BP), rice cultivation in China (7,000 BP)
Domestication Of Sheep and Goats - Site in Northern Syria on banks of Euphrates, Tel Abu Hureyra, at 9,000 BP only 19% of bones are sheep/goat, by 8,000 60% of bones are domesticated sheep/goats |
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Domestication! Why domesticate animals? Name traits we want.
What IS domestication really?
How Did Domestication Occur? |
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Definition
domesticated sheep/goats
Why Domesticate Animals? - At 8,500 BP, the end of the Pleistocene, with rapid environmental change. New species, plant and animal exploit this change of expanding grasslands and forests. The Rapid Change favors species with more genetic diversity, the ability to expand into a new environment. One source of genetic diversity is the ability to get animals to sexually mature earlier, leading to animals with juvenile characters (called neoteny) to reproduce. Juvenile, or neotenic, traits are such things as submissive behavior, begging for food, curiosity, "round heads" (in mammals), and docility, all characters that favor interaction with humans. The answer to the question Why Domesticate? - there is none. Domestication isn't just Humans "capturing" animals, BUT animals evolving to live with humans, to benefit their own survival by symbiotically living with humans.
3) How Did Domestication Occur? Conscious or unconscious selection by humans of the neotenic traits expressed in hunted animals. Re-inforcement of docility, curiosity, "disrespect" for the species barrier, submissive behavior. This could have occurred in animals drawn to the "edge" of human settlements by refuse and cultivated plants. Other explanations include the capture of the young during hunting of adults. |
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Domestication! Say what? Hunters and gatherers lived LONGER than Farmers What are the respective ages? Advantages to hunter lifestyle? |
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Definition
ut studies of present-day hunter/gatherers (e.g., The !Kung bushmen of the Kalahari Desert) demonstrate the advantages of their lifestyle (varied diet, plenty of food, little work, lots of free time, "why plant when there are so many mongongo nuts in the world?")
Bones of ancient hunter/gatherers show little disease, well nourished, no signs of physical wear or ailments. Bones of ancient farmers show malnourishment, disease, physical wear and a drop in life expectancy (Hunter bones = 27 years; Farmer bones = 19 years). So Remind Me - Why Do We Farm? |
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Period | Description | 11,000 BP to 9,500 BP | | 9,500 BP to 8,500 BP | | 8,500 BP to 7,000 BP | |
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Definition
Period | Description | 11,000 BP to 9,500 BP | No evidence of farming, hunt gazelles, gather plants | 9,500 BP to 8,500 BP | Domestication and cultivation of cereal grains; hunt gazelles (80% of bones) and sheep/goats (10% of bones) | 8,500 BP to 7,000 BP | Domestication of sheep and goats with some gazelle hunting. |
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Domestication: Before 8500 BP, no "wear" on teeth indicating After 8500 BP "bit wear" on teeth of sheep indicating Impact of Domestication On Animals - Obvious changes to create Production Traits... examples? Less obvious examples? |
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Definition
high milk production, fleece quality and quantity, lean meat, efficient growth, docility. Other, less obvious, effects include: - Body Size Reduction: Early stages of domestication create animals smaller than their wild ancestors. Later stages animals can be larger than ancestors (e.g., Shire horse).
- Outward Appearance: Selection for coat colors, wool patterns, ear length, hair length (horse mane is long; zebra mane is short and erect)
- Internal Characters: Fat is under skin in domesticates, around organs in wild animals; domesticates have smaller brains for given body size; domesticates have round face, shorter jaw - more neotenic; reduced number of teeth in domesticates.
- Behavior: Domesticates are more juvenile (neoteny): submissive behavior, curious, begging. In addition, Castration has probably been a management tool for the control of aggression since the beginning of domestication.
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Domestication! Impact of Domestication on People! More ___ Less ___ More people leads to Disease! Most come from domesticated animals! (Name 3 examples) What's vaccination? Who discovered it? Latin roots? (Think of milk maids) What happened to the natives of the New World |
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Definition
| mpact Of Domestication On People - More food, but less diverse diet. More work. More People - Leading to government, laws, society, class, everything. And don't forget Disease! Many of the diseases we commonly contract have their roots in our domesticated animals - flu, measles, smallpox ... Don't forget why we call it "Vaccination". Edward Jenner (a British physician) found 200 years ago that women who milked cows, and contracted cowpox (another viral disease we get from animals), did NOT get smallpox. They were vaccinated (Remember your Latin - vaca = cow). And of course, let us not ignore the impact smallpox had on the native peoples of the New World (who did NOT domesticate animals) when the animal-owning Europeans arrived. |
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