Food Productions Systems

During class, we made out a little investigation about food productions systems and we followed some questions.

1. Define food security and food insecurity.

Food security is that every person in a given area has daily access to food, while food insecurity is when people have no daily access to enough nutritious food to have an active and healthy life.

2. Distinguish between undernutrition, malnutrition, and overnutrition. Describe their harmful effects.

People that suffer from undernutrition can't grow or buy enough food to meet basic needs. Suffering from undernutrition may cause mental retardation and stunted growth. Furthermore, it may cause diseases such as measles and diahrrea.

People who suffer from malnutrition live in a low-protein, high-carbohydrates, and a vegetarian diet. This may cause deficiencies of protein, calories, and other key nutrients.

People suffer from overnutrition when food energy intake exceeds energy use and causes excess body fat.

3. Describe the effects of diet deficiencies in Vitamin A, iron, and iodine.

__

The lack of iodine causes stunted growth, mental retardation, and goiter, which is a swollen thyroid gland that can lead to deafness.

4. What is famine? How may it affect societies, the environment.

Famine is the shortage of food in an area accompanied by mass starvation, many deaths, economic chaos, and social disruption.

It may affect societies by having disputes about food distribution. __

5. What three systems provide most of the world's food?

The first system is croplands, which are the grains. 77% of world's food comes from croplands using 11% of world land area. The second system are the rangelands and pastures, which produce meat, mostly from grazing livestock. This system supplies 16% of world's food and uses 29% of the world's land area. The third system are the oceanic fisheries that supply 7% of world's food.

6. Distinguish among industrialized agriculture, plantation agriculture, traditional subsistence agriculture, traditional intensiveagriculture, polyculture, and slash-and-burn agriculture.

• _
• Polyculture: this means that many plants are planed together.
• Slash-and-burn agriculture: this means to clear plots of forest in order to plant crops in the ashes.

7. What is a green revolution? What limits could these have.

_

"SLASH AND BURN AGRICULTURE." College of Natural Resources and Environment. VirginaTech, 5/2/2001. Web. 13 Oct 2010. <http://www.cnr.vt.edu/lsg/intro/S&B.pdf>.

Population models

Everybody has different perspectives, in whatever the subject is. Thomas Malthus and Ester Boserup had different perspectives concerning population growth. Their own theories will be explained.


Thomas Malthus
Thomas Malthus was an English that dedicated his life into economics, demographics and political issues. Regarding demographics, he had his own thory about population. He believed that human population would grow much more faster than food supply. Furthermore, when no food was available, while population would be growing constantly (overpopulation), population will start to collapse and it would create diseases, famine, and war.

However, there is another perspective, that looks less cruel than the one of Malthus.
Ester Boserup
Estrer Boserup was a Danish economist that had a different perspective about population growth. She believed that when population grew, people would be able to handle it. This included that people would know what to do: the invention of new technologies or the implementation of systems in order to increase food supplies. This is really different in thinking than Malthus, since she believes that food supply could be increased.

References

"Maltus Theory." TalkTalk. Helicon Publishing, 2010. Web. 3 Oct 2010. <http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0034800.html>.

"Population Theories." SlideShare. N.p., 2006. Web. 3 Oct 2010. <http://www.slideshare.net/HNurton/population-theories>.

Demographics: all about rates and more

In here, there will be mentioned several rates, such as CBR and CDR, for example.

Crude Birth Rate
The Crude Birth Rate (CBR) includes the number of births per 1000 individuals. So, the formula for this is:

CBR = (Number of births / population size) x 1000

The CBR in the world is 20.3 per 1000 per year.


Crude Death Rate
The Crude Death Rate (CDR) includes the number of death per 1000 individuals. The formula for this is:

CDR = (Numberof deaths / poplation size) x 1000

The CDR in the world is 9.6 pero 1000 pero year.


Natural Increase Rate
To know the Natural Increase Rate (NIR), it is important to know the Crude Birth Rate and the Crude Death Rate, The formula for the Natural Increase Rate is:

NIR = (CBR - CDR) / 10

It is important to say that NIR gives a percentage.


Doubling time
Last semester we saw doubling time, but we didn't saw it in a clear form. Now, we saw it in class, and with this we know that doubling time is the time in years that it takes a population to double its size. The doubling time formula is:

Doubling time = 70 / NIR

This do not considers immigration nor emigration.

Total Fertility Rate
Now, continuing with rates, we have the Total Fertility Rates (TFR) which is the average number of children that each woman has over her lifetime. This one shows the potential for population change in a country.

A Total Fertility Rate that is less than 2.0 it results in population increase. But if the Total Fertility Rate is more than 2.0 it esults in population decrease.

Factors affecting species impact
Factors affecting species impact on the environment (without counting population size) are:

• Wealth, including its distribution.
• Resource need
• Resource desire

S and J curves

S and J curves is something that we say last semester. However, we reinforced it on this semester.

S-curves

This curve, as its name says it, has a shape of an S. This is an exponential growth, but then, there is a point in which growth rate slows down when population stabilizes. This one involves density dependent limiting factors.

Furthermore, the graph involves a carrying capacity (K) which is the amount of species a system can have and maintain. The carrying capcity is asymtpotic.

The curve also shows an environmental resistance which is the area between the exponential growth curve and the s-curve. This is showed at the picture below.

J-curve

The J-curve shows a boom and bust pattern. In here population grows exponentially and then crashes. This may be called diebacks, which is when the population collapses or crashes. Furthermore, population often exceeds K before the collapse occurs, which is referred as overshift.These curves are typical from microbes, invertebrates, fish and small mammals.

References (pictures)

"Chapter 6 -- Population Dynamics ." Miami University. Department of zoology, 2002. Web. 3 Oct 2010. <http://zoology.muohio.edu/oris/Cunn06/cs6_06.htm

System population dynamics

Now, we passed to other topic in class, and this one involves the population changes among a system.

First we looked at the factors that affect the population growth and these ones are divided into two: density dependent factors and density independent factors.

Density dependent factors
These ones depend on how dense the population is. These involves biotic factors and they are mostly part of negative feedbacks. The density dependent factors are derived into externa and internal factors.

• Internal factors: this ons involves the act within a same species. This includes food supply, territory, and density dependent fertility.
• External factors: this one involves the act within a different species. This includes predation and disease.

Density independent factors
These ones do not depend on how dense a population is, in other words, it is not related to population density. It involves abiotic factors and aren't part of a feedback system. Some examples of density independent factors are: weather, climate, volcanic eruptions, floods, between other.

How do we value resources?

I was looking at my notes and I saw this title. I thought it was a good idea to post it because previously, I was talking about resources, but just in the ecological way. However, there are other ways and perspectives in which resources are valued. I think it's good to be aware of them.

• Economic: this involves money. This may include the exchange of resources viewed as just "simple items" that can be exchanged without any repercussion in other areas of study.

• Ecological: this inolves the support of the systems. This may include teh awareness that there is a whole process behind a resource and also the implications it may bring to the environment.

• Scientific: this may look really related with the one above, but this is more of the research in them.

• Intrinsic: this includes the culture we have of taking care of resources, and also, trying to belong to them, not only considering them other "item" on Earth.