Artificial selection

How did we domesticate? Animal edition

Started domesticating dogs, then started domesticating for meat (primarily started in the middle east)

How did we domesticate? Plants!!

Started with barley, then squash, wheat, maize, rice, etc

Animals and plants were domesticated side by side

Domestication happens when an organism is changed by humans to better serve human needs

Natural selection vs artificial selection

Natural selection- organisms most adapted to their environment will mate and pass on their genes to their offspring, these organisms have the greatest fitness, a SLOW process → evolution

Artificial selection- purposefully breeding organisms & selecting those with the best traits (ex. cow breeders select for milk or meat), a fast process → feed the world

Plants are domesticated when an organism is changed by humans via artificial selection

Beer! The beginning of farming or “agricultural society” started 10k-15k ya, the earliest evidence of beer-making can be traced back to Natufian culture, which pre-dates the Neolithic period

Human domestication is recent

Traits that have been selected for in plants- bred that fruits will stay on the plant till ripe, increased seed production, etc.

Plant breeding: artificial selection, required: genetic variation, mate the two plants together to combine desirable traits (genes reshuffled)

Example: crab apples (small, not very sweet) → modern apples

Lots of effort goes into breeding new colors & flavors, takes 1,000 of plants

All crops come from another place, plants and animals have been spread

Humans have changed corn (now kernels can be threshed, and now they’re very large)

Sweet corn: consumption; field corn: ethanol, livestock feed, cornmeal

“Natural corn”, 7000 BC, peel it by hammering repeadely with a hard object, 5-10 hard kernals, tastes like very dry, raw potato

Artificial corn, 2014, steam cooks in minutes, easy to peel, yummy

Natural peach, 4000 BC, 1/3 is stone, tastes “earthy, sweet, sour, slightly salty”

Artificial peach, 2014, reduce stone size, and increased the size greatly

Bananas are now seedless

Brassica oleracea (a common wild mustard) has made cabbage, brussel sprouts, kohlrabi, kale, broccoli, cauliflower

Tomatoes were originally from Peru, they were the size of marbles, got bred in Mexico, then went to Europe, then back to America, domestication has brought many shapes, sizes, and flavors

Book rec: The garden of invention

Wild cotton wasn’t very good, domestication has resulted in 5x the cotton on the individual plant, also made them heartier and more resistant to diseases

The bottom line:

  1. Most of the plants you consume are not native Americans

  2. The original forms of most crops are almost useless

  3. Humans have improved crops greatly using artificial selection

  4. Plant breeding is an important job!!