Biology 2382B Lecture Notes - Lecture 7: Intensive Farming, Transgene, Rangeland
5 May 2018
School
Department
Course
Professor
Lecture 09: Global Food Production
- Carrying Capacity Can Change (through technology)!
- 10, 000 years ago transition from hunter-gatherer to agriculture increased K
- 200 to 300 y.a. industrial revolution increased K
- Now modern medical revolution increased K
Industrial Revolution
- Land we use to grow food is either Cropland or Rangeland
- Cropland land used to raise plants for human use. Cropland must arable; that is, be suitable
for the planting of annual crops.
- Rangeland land used for grazing livestock. Rangeland is not necessarily arable.
- Agriculture is a form of intensification – a way to increase the carrying capacity (K) of a given unit of
land by increasig that lads podutiit of plants and animals that we can consume
- Agriculture was invented independently across different places in different societies.
- 10,000 years ago Transition from hunting/gathering (not growing/cultivating anything) to traditional
agriculture (biologically powered agriculture – doest use iflu of eeg ia fossil fuels to die
activities that create intensification on the land; uses human/animal power).
- The oldest form of traditional agriculture is subsistence agriculture (produce only enough food for
themselves), then 100 years ago, industrialized agriculture (commercial use) took over.
- Industrialized agriculture uses mechanization and fossil fuels and relies on monoculture (vast fields of a
single type of crop efficient). Industrialized Agriculture occupies 25% of olds oplad.
- Advancements in agriculture and growth of human population size create a positive feedback:
Green Revolution
- Began in 1940s/1950s
- Technological changes in crop varieties (through artificial selection and genetic methods), irrigation
(watering plants we grow), fertilization, and other farming practices (ex. pesticides).
- Resulted in agricultural productivity by 2 methods:
1) Extensification: bringing more (arable) land into production
2) Intensification: higher productivity per unit area of land
Intensification was achieved by:
a) greatly increased use of irrigation, fertilizers, and pesticides
b) increased energy inputs (from fossil fuels)
- Once we transitioned from a hunter-
gatherer lifestyle to agricultural
intensification/growing more food,
we could feed more people and
population can grow.
- Once the population grows, there
are too many people to go back to
hunting/gathering b/c this lifestyle
at suppot ou lage populatio.
find more resources at oneclass.com
find more resources at oneclass.com
Positive impacts of the Green Revolution
a) Food Production (especially vegetables and fruits) has gone up faster than the human population
B ieasig itesifiatio, ee deeased pessue fo etesifiatio less deforestation and
destruction of natural habitats good for biodiversity).
Negative impacts of the Green Revolution
- more intensive use of water, fossil fuels, chemical fertilizers, and pesticides have led to:
a) Pollution (including CO2 pollution that contributes to climate change)
b) Erosion usig soil so itesel + e dot gie it tie to recover between growing different crops)
c) Salinization (soil becomes salty due to irrigation)
d) Desertification soil eoes aid ad at go egetatio
- recall: nutrient availability limits primary productivity (acts as a threshold)
- Fertilizers allow us to overcome this limitation
- Green Revolution relies on inorganic fertilizers (no biological origin - nitrogen, phosphorous,
potassium) as opposed to organic fertilizers (biological origin - manure, crop residue, compost)
- Fertilizer runoff leads to phytoplankton blooms (ex. algal blooms in Lake Erie) and poses human health
risks (ex. Methemoglobinemia).
- Irrigation we use most fresh-ate fo food podutio, ut e aet efficient w/our water use
(43% of water applied gets used by plants). This leads to waterlogging and salinization.
- Use Drip Irrigation as possible solution (more efficient and precise at delivering water to plants, but
more expensive).
- Monoculture devastates biodiversity, more susceptible to chance environmental events, crops are
more susceptible to disease and pests, contributes to narrowing of human diet (60% of calories
consumed comes from just rice, wheat, and corn).
- Pesticides we rely on pesticides b/c growing things in monoculture means they are more vulnerable
to pests...BUT target organisms can develop resistance, pesticides can affect non-target organisms and
pesticides may affect human and environment health.
- Food Waste 1/3 of food produced is wasted (☹). In Europe, North America, Oceania, and
Industrialized Asia, consumer waste is high but in less wealthy nations like Africa and Asia consumer
waste is lower (but waste at production to retailing level is still high).
- Lack of Food Security Food “euit = means that all people, at all times, have an adequate,
reliable, and available food supply. Food security is increasing slowly, but many people (11.3% of
olds populatio lak food seuit.
- 13% of Canadian households lack food security, 62% of children in Nunavut lack food security
- Problems w/Distribution of Food
- Undernourishment less than 90% of daily caloric needs
- Overnutrition too many calories each day (Canadian adults 48% overweight, 14% obese)
- Malnutrition not enough nutrients (vitamins and minerals).
- Demand for Meat As we become more affluent, the demand and production of meat is increasing
- Producing a quantity of beef takes a lot more resources (plant and water) than it does for
producing pork eggs chicken milk (b/c energy transfer up trophic level not perfect).
find more resources at oneclass.com
find more resources at oneclass.com
Lecture 10/11: GMOs
Theory of the beginning of Traditional Agriculture people who were gathering seeds or fruits would
have brought back the seeds from the most attractive fruits to a camp and discarded them and they
started growing. Traditional Agriculture began w/artificial selection and breeding!
3 Types of Traditional Agriculture:
1. Selective use of Natural Variants (landraces)
2. Controlled Matings (cultivars)
3. Monitored Recombination to track specific genes (improved cultivars)
Genetic Engineering Laboratory manipulation of a ogaiss geeti ateial...eates a GMO
- most common form of genetic engineering involves the use of recombinant DNA (novel DNA
sequences created by recombining the DNA of different, often distantly related, organisms).
- Transgenic organism is an organism that contains DNA from another species.
- Transgenes are the genes that have moved between organisms.
- Ma of the ops e go toda ae geetiall odified ad tasgei e. % of olds soea,
% of olds o plats, >% of all otto plats
- Most GM crops today are engineered to resist herbicides and to resist insects
Traditional Agriculture Both Genetic Engineering
- uses genes from same species - alter gene pool for preferred traits - genes from different species
- manipulates entire genome - apply to plants and animals - manipulate individual genes
Examples of GMOs
As short term agricultural
performance increases, genetic
diversity is lost
- wild relatives have the most genetic
diversity/poorest performance
- cultivars have the least genetic
diversity/best performance
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
10, 000 years ago transition from hunter-gatherer to agriculture increased k. Now modern medical revolution increased k. Cropland land used to raise plants for human use. Cropland must arable; that is, be suitable for the planting of annual crops. Rangeland land used for grazing livestock. Land we use to grow food is either cropland or rangeland. Agriculture is a form of intensification a way to increase the carrying capacity (k) of a given unit of land by increasi(cid:374)g that la(cid:374)d(cid:859)s p(cid:396)odu(cid:272)ti(cid:448)it(cid:455) of plants and animals that we can consume. Agriculture was invented independently across different places in different societies. 10,000 years ago transition from hunting/gathering (not growing/cultivating anything) to traditional agriculture (biologically powered agriculture does(cid:374)(cid:859)t use i(cid:374)flu(cid:454) of e(cid:374)e(cid:396)g(cid:455) (cid:448)ia fossil fuels to d(cid:396)i(cid:448)e activities that create intensification on the land; uses human/animal power). The oldest form of traditional agriculture is subsistence agriculture (produce only enough food for themselves), then 100 years ago, industrialized agriculture (commercial use) took over.
