BIOLOGY 157: LIFE SCIENCE: AN ENVIRONMENTAL APPROACH (Energy needs: Food)

ENERGY Energy is the ability to do work Humans use energy of two types Internal (= food) External or Auxiliary (= fuels, etc.)

INTERNAL ENERGY (= FOOD) I If all of our food consisted of vegetation then about 0.005% of the net primary production would suffice to meet the caloric needs of the world’s humans. If we were completely primary carnivores then it would take 0.05% (following the 10% ‘rule’) The real value is somewhere between and WHY?

INTERNAL ENERGY (= FOOD) II REMEMBER, most of the NPP is not available to us for food because it may be: inedible used for building materials used as fuel used for paper, packaging, etc. used by other organisms ‘wasted’ between production site and point of use

HUMAN CALORIC REQUIREMENT Obviously the need varies from person to person and from situation to situation. An average value is that a person needs 2,200 calories a day (and, of course, the foods must contain not just energy but all the nutrients the body needs) males ,400 calories females --- 2,000 calories

CALORIC SOURCES Should humans, as a species, be considered herbivores or carnivores? Grains % Meat (excluding fat) % Fish % Lipids (fats and oils) % Tubers % Other fruits and vegetables % Sugar %

GREEN REVOLUTION This term refers to a series of projects whose intent was to increase basic primary productivity (especially in less developed, mainly tropical) countries through the use of new grain strains and improved farming practices. Post WWII Norman Borlaug ‘father’ of the green revolution work began in 1944 on wheat Nobel Peace Prize

NUMBER OF GREEN REVOLUTIONS In reality there has been more than one GR 1) beginnings of agriculture 2) invention of the plow 3) development of irrigation 4) with crop exchange from various regions of the world 5) mechanization in early part of the 20th century 6) first modern GR ’s in MDC’s 7) second modern GR --- late 1960’s in LDC’s

GREEN REVOLUTION CROPS Most of the effort in the modern green revolutions has been devoted to grains. WHY?

SUCCESSES OF THE GREEN REVOLUTIONS None of the GR’s have been completely successful. increases in productivity are often ‘eaten up’ by increases in population size. Thomas Malthus All GR’s have had flaws and / or problems.

WORLD GRAIN PRODUCTION

WORLD GRAIN PRODUCTION PER PERSON

WORLD FISH CATCH

WORLD FISH CATCH PER PERSON

OUTCOME OF THE MODERN GREEN REVOLUTIONS In the late 1960’s / early 1970’s –India’s wheat crop up 50% –Pakistan’s wheat crop up 60% –Pakistan’s rice crop up 162% –Philippines rice crop improved so much that it went from a rice importing country to a rice exporting country –Many other countries experienced considerable increases

GREEN REVOLUTION PROBLEMS Some of the increases attributed to GR were in reality due to a favorable weather cycle ‘tech fixes’ often spawned problems –GR varieties dependent on optimal conditions; developed for temperate mass agriculture techniques (monoculture, mechanized harvesting, pesticides, fertilizers, etc.) –When times got tough (middle to late 70’s) poor countries could not afford machinery, fuels, pesticides, fertilizers, hybrid seed, etc.) –population displacements –spread of disease due to irrigation (Schistosomaiasis) –some new crops / varieties not acceptable to the people –destruction of lateritic soils –tropical climates and day length often reduce the productivity of a certain crop

INCREASING FOOD PRODUCTION (I) Increase amount of land in cultivation or as pasture Increase yield from currently cultivated land by: using improved and appropriate farming practices better pest and disease control irrigation, fertilizing multicropping, intercropping, polyculture use new, higher producing varieties ‘standard’ cross breeding vs. genetic engineering

INCREASING FOOD PRODUCTION (II) Conserve!!!!! (= less waste) (better harvesting, improved transportation and storage) only raise those species that yield truly useful and nutritious materials processing into useful forms Harvest / Raise a wider variety of species for food (20 species of plants and 10 of animals provide 90% of our food)

SOME THINGS FOR YOU TO INVESTIGATE (CHAP. 7) Does the current world production of food allow for sufficient food for everyone? What is the difference between Kwashiokor and Marasmus? How do these relate to Malnourishment? What are GMOs? Is tilling soil good? SOIL --- Don’t concern yourself with the actual soil horizons but do know what soils are and how they form. What is a locavore?