1. Plant and Animal Domestication

2. Jared Diamond, Guns, Germs, and Steel

3. Why Farm?
Hunting and gathering can supply a day’s calories with a couple of hours’ work
Many early farmers less well off than hunter-gatherers
Line between hunter-gatherers and farmers is fuzzy
In rich environments, hunter-gatherers may have permanent settlements (Pacific Northwest)
May practice some agriculture along with hunting and gathering (Apaches)

4. The Ice Age and Agriculture
Sea level rise stops about 7000 years ago
Agriculture spreads widely roughly same time
Stable coastal plain and river valley environments
Warm, dry climate favors spread of wild grains
Extinction of megafauna (and domestication candidates?)

5. Mediterranean Climate
Dry Summer, Rainy Winter
Favors plants with seeds that can survive long dry periods
These seeds can be stored for extended periods
Will not spoil or germinate while dry
Eurasian Mediterranean is world’s largest zone, greatest ecological diversity in small areas

6. The Fertile Crescent

7. Large Seed Grasses 56 species, <1% of total grass species
Eurasian Mediterranean 32 species
Rest of Eurasia 7 species
Sub-Saharan Africa 4 species
North America 4 species
Mesoamerica 5 species
South America 2 species
Australia 2 species

8. Human Plant Environments
Select desirable plants in wild
Some seeds, fruits scattered at habitation site
Other seeds deposited in wastes
Eventually have desirable plants growing close-by
Protection from foragers
Seed collection

9. Plant Domestication More than just planting seeds or transplanting
Most plants inedible or otherwise unusable
Most plants unsuited for primitive domestication
Not every locality has abundant plants suitable for human use
Need nutritional balance
Requires changes in plant characteristics

10. Highland New Guinea Simple agriculture for thousands of years
Active experimentation and inquiry
Chronic protein deficiency
Introduction of sweet potato (South America via Philippines) caused population boom
These people knew their environment as well as any people on earth
If any local plants could have been successfully domesticated, they would have found them

11. Five Levels of Domestication
Unconscious selection of plants for desirable traits (9000 BC)
Conscious cultivation of plants with desired traits (BC)
Deliberate breeding to improve traits (1700)
Scientific breeding: genetic mechanism known and exploited (1900)
Direct genetic manipulation (2000)

12. Reversing Natural Selection
Seed Scattering
Non-bursting pods (peas)
Non-shattering heads (grains)
Fruits without seeds
Germination Inhibition
Nature: favors seeds that germinate slowly and over time
Agriculture: favors seeds that germinate quickly all at once

13. Reversing Natural Selection
Deterrents
Loss of Toxicity (Almonds)
Changes in Reproduction
Asexual Reproduction
Self-Fertilization (Hermaphrodites)
Annuals favored: would evolve more quickly under artificial selection

14. Plant Domestication Single Mutation
Chance of getting multiple favorable mutations very slim
Self-Pollinated or Asexual Reproduction
Pollination from elsewhere would negate mutation

15. Some Non-Domesticates
Oaks
Food Source in Many Places
Grow Slowly
Bitterness Controlled By Many Genes
Seed Dispersal by Animals
Berries
Domesticated only after greenhouses invented

16. Fertile Crescent Founder Crops
Emmer Wheat
Einkorn Wheat
Barley
Lentil
Pea
Chickpea
Bitter Vetch
Flax

17. North American Crops Gourds Sunflower Sumpweed (seed crop)
Goosefoot (leaf crop)
Corn (from Mexico)
Beans (from Mexico)
Squash (from Mexico)

18. Agriculture and Civilization
Why the Link?
Need for organization, surveying, record-keeping
Surpluses allow development of specialist classes
Protection?
Grain stores susceptible to raiding

19. Animal Domestication
Genetic change that makes animal more amenable to human control
Not the same as:
Taming
Training
Captive Breeding
A lot more complicated than just capturing and taming animals

20. Animal Domestication
Happy families are all alike. Every unhappy family is unhappy in its own way. --Tolstoy, Anna Karenina Lots of things have to work for success. Failure in any one means failure of it all.

21. Unsuitable for Domestication
Ferocity (Zebras, Rhinos, Hippos)
High Trophic Level (Carnivores)
Picky Diet (Pandas, Koalas)
Slow Growth (Elephants)
Territoriality (Deer, Antelope)
Large Range
Solitary Habits
Reclusive Breeding or Elaborate Courtship (Cheetahs)
Tendency to Panic (Gazelles)

22. Suitable for Domestication
Docile (or selectable for docility)
Non-territorial
Dominance Heirarchy (Humans co-opt leadership role)
Uninhibited Breeding
Rapid Growth a plus

23. Thyroxine Governs many growth and maturation characteristics
Governs adrenaline (fear response)
Low thyroxine traits:
Reduced snout (pedomorphism)
Solid or patchy colors
More frequent reproduction
Larger litters

24. Self-Domestication Humans create an environment Free of Predators
Abundant food
Salt

25. Animal Domestication 148 Species of Large Herbivores (>50 kg)
Eurasia 13/72 (18%) Domesticated
Sub-Saharan Africa 0/51 Domesticated
Americas 1/24 (4%) Domesticated
Australia 0/1 Domesticated

26. The Big Five Sheep Goat Cattle, Oxen Pig (Actually an Omnivore) Horse
All are Eurasian

27. The Lesser Nine Arabian and Bactrian Camels (Eurasia) Donkey (Eurasia)
Water Buffalo (Eurasia)
Yak (Eurasia)
Bali Cattle, Mithan (Eurasia)
Reindeer (Eurasia)
Llama (including Alpaca) (South America)

28. Why Eurasia?

29. Why Eurasia? Only Land Mass with east-west axis Other barriers
Panama and Caribbean
Rain Forest (Africa)
Trypanosome Belt (Africa)
Extinction of Megafaunas
Not adapted to humans and vice versa
Possible candidates for domestication wiped out?

30. Why Not Domestication?
Buffalo (bison) and elk successfully farmed in modern times
Have attributes that seem promising for domestication
Wild grapes in America not cultivated
If advantages marginal, domestication may not happen even if possible
Indians adapted to Horses Very Quickly

31. Domesticated Carnivores
Dogs
Have dominance hierarchy that humans can co-opt
Cats
Probably attracted to prey around grain stores
At best partially domesticated
Ferrets
Recently popular as pets but long used for pest control
Probably many of same factors as cats

32. Small Animal Domestication
Thousands of Candidates
Distinction between Domestication and Captive Rearing fuzzier
Do We Really Care if a Rabbit is Captive or Domesticated?
Very Rapid Breeding Cycle