2 artificial selection
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Artificial Selection
Domestication & BreedDevelopment
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To Succeed with Domestication
Adapt to environment
Provide nutrition needs
Meet social requirementsMust consider typical social organization of species
How to young learn to be adults
Problems
Vices, Aggression Impotence, Infanticide
Able to reproduce
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Domestication of the Horse
23,000 B.C.Southern France archeological site
Food cracked bones of as many as 100,000horses
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Start of Primitive Agriculture
4500-3500 B.C. Less nomadic Depletion of local herds Domestication
Means of dependable food supply Taming by-product of hunting Orphaned foal 2-12 months of age Adopt, raise and put to work
Ex. Turkestan Turkmenes Lived on mares milk and horse meat - Raised fillies/ate colts Tethered mares in season for wild stallions to breed Earliest selection criteria Milk Production
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Domestication of the Horse
Ass, Onager & Camel
domesticated before the
horse 3000 B.C. drawings of
Onager being ridden with a
nose ring and jaw strap
Horse domesticated in
numerous areas duringsimilar time period 3000-2300 B.C.
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Signs of Domestication
Caves of Sumeria (Perisian Gulf) 2800 B.C. First signs of selective breeding
Drawings of horse heads in 4 horizontal rows Different head profile types (convex, straight,
concave) and mane types (erect, hanging and
maneless)
Central Asia 2800 B.C. Drawings of horses hitched wearing snaffle-type bits
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Earliest Selective Breeding
TemperamentThose that refused to obey returned to wild or
used for meatMore agreeable animals remained in
comparative safety of captivity
Bred to other docile animals to produce good-
tempered foals
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Earliest Selection Criteria
Learning Ability - Trainability Horse transferred reliance to man
Food, protection and companionship Learned to overcome fears hunting lions, tigers, etc.
Xenophon 430 B.C. first recorded advocate of
training by reward.
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Other Traits
Speed and SurvivabilityWithhold water for several days
Release herd pointed in the direction of water
First to arrive were selected for breeding and
training
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Man Alters the Horse
Orthopedic Problems1000 B.C. Xenophon first asserted no foot,
no horse
500 B.C. Persians develop first horseshoes heavy cloth Other problemsOccurrence of genetic abnormalities
May select beauty over functionality Small, dainty hooves
Selection criteria for performance reducedversatility
Breeds
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Breed Development
Breed = group with distinctivecharacteristics that are transmitted to their
offspring. Initial development through natural
crosses and artificial selectionEnvironment important roleAdaptations of the 4 original types
Results in many breeding groups
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Breed Development
Distinctive Characteristics Extremes in Climate, Topography and Vegetation Conformation
Color Performance
Skills and Abilities well promoted by breed advocates
Intelligence
Disposition Suitable to Mans Purpose gaits
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Formal Development
Man bred early types to fix certaindesirable characteristicsLittle change if type was suitable
pony breeds are relatively pure almost directdescendants of one early type
Some breeds took centuries Outcrossing with numerous other breeds
Easiest to develop if trait can be fixed (set)
Get desirable and undesirable characteristics set One sire may have strong prepotence good and bad
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Genetic Evidence
DNA of ancient wild horses found in permafrost Sweden & Estonia 2000yr old remains, Alaska
28000 yr old remains Analyzed the mitochondria DNA
Mutations occur at a known rate = molecular clock
Maternal ancestry traced
Tested against 600 living horses From 25 breeds worldwide
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