How to Grow a Planet - Humans on Earth (Lecture 11)

When did farming begin?

~ 12,000 - 10,000 years ago

What were the first plants to be domesticated? Where were they domesticated?

• Wheat, barley and chickpeas in Middle East

• Rice and soy beans in Asia

• Maize and fava beans in the Americas

How did bread wheat evolve?

• Einkorn (14 chromosomes (n)) naturally hybridised with another grass (14n) forming emmer wheat (28n) - which has 2 genomes

• Then another hybridisation – this grass sp. was 14n - to form bread wheat (42n)

• The more genomes a plant has, the more robust it is and the faster it grows

What was the Green Revolution?

Series of developments which led to an increase in agricultural yields in a short amount of time

What was Thomas Malthus’s theory? What is a Malthus catastrophe?

• Theory - Population grows with subsistence therefore the more able to grow, the larger population able to sustain

• Malthus catastrophe when population higher than means of subsistence = lower food security

What did Ernst Borlaug do in the Green Revolution? What were 2 issues with his work?

• Made plants to focus energy on seed production rather than height

• Wheat got smaller and smaller → produces more seeds

• Shorter plant = higher harvest index → increases yield

• Helps with food security

• HOWEVER…uses chemicals

• Growth of wheat yields stopped late 1990s/early 2000s

What else did Ernst Borlaug contribute to Green Revolution?

• Wheat stem rust fungus affecting yield

• Led plant breeding to produce resistance

  • HOWEVER…evolution produced new varieties of thw fungus

Name and explain 3 projects which improve food security.

• C4 Rice Project

  • Take characteristics from maize and put them into rice

• Golden Rice

  • Help solve vitamin A deficiency à low vitamin A = worse vision

  • Not accepted, had many difficulties when attempting to implement into society

• Salt Water Cress

  • Extremely stress resistant

  • Look at genes and try to implement into other plants or grow

What is agroecology? Give 4 examples of this.

• Agroecology - the application of ecological principles to agricultural systems and practices, or the branch of science concerned with this

• Intercropping

• Soil management

• Agro-forestry

• Integrated pest management