BIOB38 - Flashcards

Farming employs

45% global working population, 80% of developing countries (in Asia and Africa) labour force

Neolithic revolution

Making food as a small community turned into groups doin back breaking labour in large populations. Started nomadic and living in small family communities, and ended sedentary and living in larger and denser populations.

HG time

Lots of time for leisure (making tools and art). Art left behind a testament to life history. Cave paintings in France and Spain that were produced pre-rise of agriculture and depicted commonly hunted animals.

HG food composition

26-35% - Plants

26-35% - Meat

0-65% - Fish

66-100% - Meat and Fish

• Paleo diet: very different to us.

HG health

General bone health, proper joint, teeth and posture. More efficient than agriculture. More well-rounded and healthy than farming. Largely nomadic.

Collared peccaries

65 000 calories in one hour, better than seed, which highlights animal vs plant based foods

Agriculture mechanised

Use of fossil fuels. Corn, rice, wheat, very low energy gained by energy invested.

Fertile Crescent

Saw the first transition into farming. It was a slow process. In the Near East (Palestine, Syria, Babylon), people were cultivating rye fields (13 000 BP), and then only started living in villages 12-10 000 Y BP.

Primary Centers

1. Fertile crescent (Middle East) (10 000 y BP)

2. Southeast Asia (9000 y BP)

3. New Guinea Highlands (9000-6000 y BP)

4. Subsaharan Africa (5000 - 4000 y BP)

5. Mesoamerica and N South America (5000-4000 y BP)

Key depictors of a primary center

An area where local plants and animals were domesticated, an area where the idea of how to grow food was originated. They hunted and gather species.

Secondary centers (primary → secondary)

Fertile crescent → Europe

Southeast Asia → Further south (indonesia) + Madagascar

New Guinea → Indonesia

Subsaharan Africa → Southeast africa

Mesoamerica and N South America → More parts of USA and South America

Secondary centers

Mediterranean, North-Eastern Africa, South-Eastern United States

Domesticating plants

Flowering plants - 275 000

Plants eaten by people - 2500 (1% of angiosperms)

Plants in world commerce - 150

Major economical importance - 20

Fertile Crescent

Barley, Wheat, Chickpea, Lentil

Southeast Asia

Rice, Chinese millet, Soybean, Chinese cabbage.

New Guinea Highlands

Taro, Sugar Cane

Forests: Cane sugar, banana, grape

Subsaharan Africa

Sorghum, Millet, Teff, Coffee, Yam, Pigeon, Pea, Cowpea

Americas

Potatoes, Tomatoes, Corn, Common Bean, Squash, Quinoa

Top 20 crops

Most come from the Savanna and the Mediterranean. Cane sugar, Maize, Wheat, Rice, Potato, etc.

Cost of switching to agriculture

• Lower quality food

• Spent all day working

• High risk of starvation

• Plague fest

• Lots of chronic disease

• Heavy social hierarchy

Early farmer health

Higher inflammation, small body size, iron deficiency (plants have less iron than meat), short lifespan (7 years shorter), weak and unhealthy teeth.

Climate change theory

The ice age ended 14 000 y BP, and so hunting and stuff was good and moist, but then 12 000 y BP the “Younger Dryas” came and caused food stress and people had a need to supplement agriculture.

Natural habitat hypothesis

Taurus and Zagros mountains are naturally open steppe vegetation (Fertile Crescent) with lots of grasses, relatives of wheat and barley. Looks as it is today. Opportunity and previous experience of grain gathering.

Competitive feasting model

Locally dominant tribe gathers annually, many people for several day (ritualistic/religious/societal meetings) → display of power. Goebekli Tepe. Producing more non-perishable foods

Goebekli Tepe

Massive structure where no one lived, evidence of seed grinding and feasting (fertile crescent). Excavated 30 years ago. Stones turned grass seed into flowers, then started organizing. Massive pillars you can’t construct by yourself.

Demographic theory

Evidence that villages are older than start of agriculture. Increasingly sedentary/large population → reached carrying capacity and needed more food than could be hunted and gathered.

Co-evolutionary adaptation of plants and humans

Plants adapted to be dispersed by humans. We have changed landscapes, but plants have also changed a lot. Apples became larger and juicier, so we produce more of them.

Consequences of Neolithic Revolution

• Human population went starkly up (couldn’t return)

• Per unit area, agriculture provided more calories

• More work, created jobs

• More non-perishable foods

• Transportation came to be (ideas, disease, war)

• Population density (up, drastic at early irrigation)

Nomadic herding

Landscape is too dry to grow food, so the herders follow the wave of green with their domesticated animals (following the monsoon)

Northern Africa, Middle East, Middle Asia.

Shifting cultivation

Soil in tropics are too unproductive, so people take down trees, grow crops and exhaust soil for 6-12 years, then they must clear the land and move on.

Central Africa, Central South America

Plantation agriculture

No cold winters, so farmers grow perennials and woody plant species. They plant things and harvest them every year. Mediterranean fruit perennials elsewhere.

S North America, the islands, N South America

Mediterraneans farming

In areas with dry summers and mild winters, they’re less limiting and so there is a mix of having orchards and having nothing. Citrus and olive trees. Farmers also cultivate gardens with grains, roots and vegetables.

Edges of the Europe, Africa, Middle East region.

Rice paddy farming

In tropical areas with regular monsoon brought-on rain

Southeast Asia

Dairying

Cows kept indoors for their milk, the land produces feed for cows. Temperate and moist areas.

Ontario, Northern Europe

Livestock ranching

Livestock kept outdoors to feed on land. Less productive land than dairying (drier land). Motivation for beef, where cows are allowed outdoors.

The rockies, lower Brazil, Argentina, Australia, South Africa.

Commercial grain farming

Temperate climates. Needs to be moist enough to allow grasses to complete their lifecycle. Moderate precipitation

Argentina, Turkey, Southwest Russia

Market farming

Lots of water needed, water temperatures. Food is highly perishable, fossil fuels used for transportation often and quickly. Productive areas where food need to be quick so to not perish. Fossil fuels for fast transport.

California, Southwestern Europe

Grasses

Corn, wheat, rice, barley, rye, spelt, millet, sorghum

Legumes

Soybean + all other lentils, peas, chickpeas

Wheat form

Stem → Rachis

Seed → Spikelet

Whole thing → Ear

Undomesticated wheat seed lifecycle

Cells in the rachis undergo programmed cell death, and the rachis falls apart (shatters) into individual spikelets. The spikelets disperse with the seed away from parent plant. This forms a smooth abscission layer at the spikelet bottom

Non-shattering wheat seed

2 genes are responsible for spikelet to free itself. Randomly occurring mutation where gene is no longer functioning and seeds WILL remain attached, where they are characterized by a frayed rough edge. These seeds do not fall on the ground. This means there is no controlled cell death of rachis.

Ripe seeds

More nutrient → early farmers collected seeds from yellow plants

Threshing

With a stiff rachis, you have to break wheat down to get the seeds. Hitting them, manually with cows, ends with rough spikelet. We have mechanical version now.

Tilling

Prepare and cultivate land for crops

Dormancy

Mechanism to prevent germination during unsuitable ecological conditions, then the probability of seedingling survival is low. There is no growth, no germination. Seed waits for good environmental conditions.

Vernalization

Exposure to cold temperatures of freshly produced seeds native to a winter-cold climate

Photosensitivity

Mechanisms to keep track of changing daylight in order to germinate ahead of the hot and dry summers. Wild plants in summer-dry climates need to remain dormant during the most severe bottleneck season.

Perennial → annual

They harvest in year 1 rather than no fruiting in year 1. Farmers want annuals so they can do it year round and can harvest throughout.

Sunflower effect

Went from having many small heads to one/few larger flowering heads. If you harvest from many, it is more work than everything being in one place.

Increased palatability

High levels of defence makes them toxic, and we pick less toxic, wild annuals and as it gets more and more domesticated, there is a decrease in defense ending up in agronomic selection → reduction of defense chemicals, and we need to protect with pesticides.

Lima beans

Wild-type contains toxic cyanogenic glycoside, while domesticated has much decreased or is completely absent.

Nightshades toxic

Contain alkaloids, and domesticated to lose this. Some have leftovers. Many middle age people have autoimmune diseases and they are very sensitive to chemicals from nightshades

Corn diversification

Dent, flint, pop, flour, sweet, waxy.

Different in starch, sugars and water content. Shells are very different.

Potato diversification

Russet, red, white, Yukon gold, blue, fingerline.

You can work with them differently, like baking, boiling, frying, roasting, au gratin, scalloped, mashin, steaming.

Outcrossing losses

Reduction of seed dispersal, increase in seed size/number, loss of dormancy, shortening of life cycle, more compact growth habitat, higher palatability and diversification

Chasmogamy

The flowers when cross-polinated have the advantage of sexual reproduction between two different parents, resulting in genetically distinct seeds.

Cleistogamy

Flower bud never opens and organs are bunched together in the bud (beneficial to farmer)

Rhizomes

Potato, ginger, taro, cassava

Modified stems below ground. Asexually, there’s a fixation of good genotypes.

Plant reproduce asexually through these and sexually through seeds.

Stolons (runners)

Strawberry

Propagate asexually through cutting stolons (modified stems above ground), fixates on good genotype. In sexual reproduction, stems grow horizontally above soil in the middle growing out.

Rooting of branches

Banana, coffee, cocoa, tea, etc.

Sugar cane produces seed but it is propagated asexually through cutting stems into pieces, which regrow into adults. Favours good genotype. Sexually flowers. One side unit and it will regrow stem and roo. Reproduce a bunch from one sugar cane. Clonal monocultures.

Grafting

Grape, apple, pear, peach, etc.

Cut off branches and quickly replant them in existing root base, allows them to keep growing. How you get good grapes from a successful line forever. Tissues reconnect and branches on top have different genetic makeup, growing year after year.

Pre-science

11000 BP - beginning of plant domestication, Fertile Crescent

• Ancient times, non scientifically by farmers into the renaissance. Food production became what it is today.

Renaissance to pre-DNA discovery science

1694 - plant crossing → obtain new plant types

1761-1766 - Discovery: hybrid offspring has traits from both parents

1866 - Mendel: experiments in plant inheritance

1900 - Mendel’s law of inheritance rediscovered

1920 - Discovery of hybrid vigor

Post-DNA discovery science

1944 - DNA is hereditary

1953 - Description of DNA structure

1972 - Discovery: Recombinant DNA technology

Mass selection

Most was unconscious, and we see a need for variability in a population. There are rounds of recurrent selection. Based on phenotype and functional difference, genetically speaking people didn’t know they were doing selection through the use of genetics.

Hybrid breeding

Renaissance of science. Inter-fertile species crossing. Between species crossing. Mendel’s rules followed.

Heterosis

Two distantly related animals have offspring and it outcompetes either parent (bigger, strong). Can happen between and within species.

Wheat hybridization

Eikorn Wheat¹ x Goatgrass² = emmer and durum wheats³ (pre-agriculture)

Emmer and durum wheats³ x Goatgrass⁴ = bread wheats⁵ (early fields of Fertile Crescent)

Corn hybrid breeding

Used heterosis for hybrid vigor (got large ears of corn). 400% higher productivity in hybrids.

Male inflorescence, pollen leaves inflorescence and joins the female inflorescence (at the bottom). Wind pollinated = monoecious species.

Tassel (male inflorescence, at top of the plant), ear (female inflorescence, in axils of leaves), silk (long stigma), corn secual system (monoecy - both sexes on one plant)

Process of Hybrid Breeding

1. Pick good candidate

2. Self good candidates to turn them from likely heterozygous to homozygous

3. Screen selfed offspring, keep food for further selfing, discard bad

4. Cross the homozygous candidates to create offspring seeds (goal)

5. Go through steps at a massive scale (sell to farmers)

Hybrid breeding pros and cons

Pros

• Reproducible

• Predictable

Cons

• Only possible in crossable species

• Only possible with dominant traits

• Very slow process

• Breeding program needs to start anew after each season

Mutation breeding

Post-DNA discovery science. Using chemical mutagens or radiation to generate mutants with hopefully desirable traits. May involve any trait, e.g. from minute to drastic morphological changes.

Physical mutagenesis

Ionizing radiation (IR), UV rays, X rays, gamma rays

Chemical mutagenesis

compounds interacting with DNA (mutagens) - more effective than physical techniques and easier to fine-tune. Should have an affinity for reacting with DNA.

Ionizing radiation

Scientists grow different species and see how far out the radiation goes. They make cell and radiate them on a smaller level. Screen for hopeful monsters.

Mutation breeding pros and cons

Pros

• Applied to single cells or whole organisms

• Screen very large populations (of individuals and cells)

• If introduce to germline to get a stable trait.

Cons

• Non-heritability of many mutation (outside germline)

• Requires dominant mutation (or double recessive mutation); most mutations are recessive and single

• Unpredictability of mutations

Backcross breeding

Post DNA discovery science. Transfer a desired trait from donor parent into the favoured genetic background of the target cultivar. Applications → improvement of established cultivars.

Backcross breeding pros and cons

Pros

• Reproducible

• Predictable

• Fully inherited trait

Cons

• Only possible in crossible species

• Slow process (multiple generations needed)

Genetic Modification

Post DNA discovery science. Regardless of relatedness between donor and recipient → source of novel traits.

DNA from one organism put into (recombined) DNA from another organisms (recombinant DNA). Identify a gene of interest, grab DNA from donor organism, put into recipient.

Agrobacterium tumefaciens

Free-living soil bacterium, tumefaciens is cancer making. If it infects plant, it makes cancerous ball or structure, ideal housing unit. Tumefaciens means cancer making.

A. tumefaciens process

Mature plant (herbicide susceptible) → tissue culture to differentiate mass of cells → culture inoculated with recombined bacteria including herbicide resistance gene → herbicide addition kills all be recombined plant cells → undifferentiated cells spit apart and grown in liquid culture → regrowth of a recombined plant cell into plant embryo → embryo grows into seedling → mature plant (herbicide resistant)

Golden rice

GM, motivation to deal with vitamin A deficiency. Humans metabolisms can only take up this vitamin A with fat in your diet so poorer populations lacked in this too. Insert 3 genes into rice, 2 from daffodils and one from bacterium. Beta carotene.

Hungriest places

Guatemala, Sierra Leone, Niger, Mali, Burkina Faso, South Sudan, Somalia, Mozambique, Zambia, Lebanon, Bangladesh.

Norman Borlaug

Biggest contributor of the GR. Studied in Minnesota, researched in Mexico and worked in India. He worked mostly with the wheat and rice in India. Brought new and productive varieties of wheat and rice.

GR wheat

Mexico and India. Loss of day-length sensitivity (two harvests and cultivation anywhere, no more dormancy), introduction of several resistance genes (backcrossing), Dwarfing (breeding to be smaller). 4-5 fold increase in production (Mexico).

GR rice

India. Dwarfing, faster life cycle (more than one crop per year).

Green Revolution changes

• Commercialization of food production

• Heavier use of fertilizers

• Heavier use of pesticides

• Increased cost to farming

• Increased dependence on irrigation

• Increased involvement of large breeding companies

• Industrialization of farming

• Use of heavier machinery

Famines (India)

4 huge ones from 1770-1800 and another in 1850-1876. The seemed inevitable, like they were based on the monsoon, however with better management, 5 from 1800-1825 could have been avoided.

1943 Bengal famine

5 million deaths, not caused by decreases in food supply, by socioeconomic dynamics and failure of public action.

Why did so many people die - a whole lot of rice and wheat was exported

Florence Nightingale

British nurse stationed in India who witness ofe of the disastrous famines from 1875-1900 which killed 26 million Indians.

Vandana Shiva

Indian economist and philosopher who won a Nobel Prize in economics, was a huge skeptic of the famines in India. critic of green revolution. Right Livelihood Award, Global 500 Award of the UNEP, Earth Day International Award of the UN

Main exports from India

Opium (UK → China), wheat, rice, indigo, cotton

Famine graph

Valley = El Nino, no or smaller than average monsoon

Peak = La Nina, larger than average monsoon

Post-harvest loss

30% of food we produce is wasted after the harvest. Local farmers have places to grow lots of tomatoes, mass rotting of perfectly good food just after harvest because it is not fast enough to get in stores.

Obesity pandemic

Oceania (island populations) have more than 50% of their population obese, because they only have access to unhealthy foods. Makes up the entire top 10, US in 11th. Vietnam and Bangladesh are lowest weights.

Increased meat production

Primary herbivores to carnivores, each produces a bunch of calories, and so we only allow us to eat 1% of what they ate in terms of energy. Eating so much meat is a waste of calories. Turkeys are more effective than swine, than eggs, than beef cattle, then lamb (worst).

Social effects of GR

Expensive for poorer farmers, increased intensification (chemical costs go up), making less income than average, surplus yield (dump, sold internationally, effects food costs), debt, land exodus.

Intermediate farms

Highest crop production value per capita. Work more likely done by family. Can often afford mechanization but not as much unnecessary shit.

Big farms

• less yield/acre

• land left idle

• more profitable and competitive

• have more overuse of soil, chemicals, fossil fuels

• remove wealth from rural communities