Terrestrial VS Aquatic Food Production

Next, is a comparison between terrestrial and aquatic food production.

Terrestrial:

• Food harvested from 1st or 2nd trophic levels thus more energetically efficient.
• Solar energy capture (GPP) more efficient.
• Energy transfers between trophic levels not as efficient. 

Aquatic:

• Most food is harvested from higher trophic levels, thus not as efficient
• Solar capture (GPP) not as efficient due to absorption of sunlight by water
• Energy transfers between trophic levels fairly efficient.

Farming and production systems

There are several types of farming systems

1. Subsistence: provision of food for family and their community; little or no surplus; mixed crops; extensive use of human labor; low use of fossil fuels, chemicals, and capital; little technology.

2. Commercial: large profit generating scale; maximized yields, monocultures; high levels of technology, energy, and chemical inputs.

MEDC vs. LEDC

MEDC (Most Economically Developed Countries)

• In many MEDCs, the cost of staple food items is relatively cheap. 
• Most people make purchases based on taste and preference.
• Produce seasonality has mostly disappeared due to globalization. This has also allowed for a greater international variety in most supermarkets.
• In MEDCs the average caloric content per capita per day of food is 3314 calories. In the USA specifically, this number is 3774 calories.

LEDC (Least Economically Developed Countries)

• In LEDCs, many staple food items may not be always affordable as prices fluctuate. 
• People tend to make purchases based on nutritional need and affordability.
• Political and economic agendas can affect food production (e.g. cash cropping)
• Even if food crops are not used as cash crops, food production is still impacted since arable land is being occupied all the same.
• In LEDCs the average caloric content per capita per day of food is 2666 calories. In Eritrea this number is 1512 calories.

Demographic Transition Models

Demographic Transition Models describes the pattern of decline in mortality and natality (fertility) of a country due to social and economic development.

Can be describes as a 5-stage model:

1. Pre-industrial
2. LEDC
3. Wealthier LEDC
4. MEDC stable
5. MEDC population decline.

Type of population pyramid shapes

There are several types of population pyramids and are divided into four stages, which are:

Stage 1: Expanding - High CBR, rapid fall in each upward age group due to high CDR, short life expectancy.

Stage 2: Expanding - High CBR, fall in CDR as more individuals live to middle age, slightly longer life expectancy.

Stage 3: Stationary - Declining CBR, low CDR, more individuals live to old age.

Stage 4: Contracting - low CBR, low CDR, higher dependency ratio (those that cannot work), longer life expectancy.

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.

What is sustainability?

On class, everyone made their definition of sustainability. My definition of sustainability was:

The process of maintaining certain things, activities, or situations by themselves (this may include a system), but in a way that it could be preserved for future generations.

Talking about sustainability, on school, we had a congress which was called EPSA (Encuentro por la sustentabilidad ambiental). This one has the task of finding sustainable solutions for the world of today. The main topic was the aiding of a community called "San Gilberto" which was affected by the hurricaine "Alex".

We had to find sustainable and realistic solutions for the problem. We worked in teams and by the end of the congress we had several solutions, and some of them were:

• The education of the community (this also included the education of teachers about sustainability so they could also teach their students)
• Reforestation
• The cleaning of the area
• Between others more

Natural Capital

Here are some of the notes taken in class concerning the economic resources topic.

Before passing to the natural capital section, it is important to know what does an economic system and resources mean.

Economic resources is a system tha produces and distributes goods and services by using natural, human, and manufactured resources.

An economic system is a system that produces, distributes, and consumes goods but also services to satisfy the people's needs and wants in an effective and efficient manner.

Resources may be also called as capital. It is important to say that when we refer to capital, we refer to the use or the production of goods and services, which this last one (capital).

There are three types of capital:

• Natural capital
• Human capital
• Manufactured capital

Natural capital and nautral income
Natural Capital
What does natural capital includes? Well, natural capital inclueds resources that have value and those which support life. Some examples of this are:

• Trees, soil, water, living organisms, ores (which are deposits were nuberaks are extracted for materials).
• But also floods and erosion protection by forests.

Furthermore, natural capital can also process photosynthesis and cycles such as water and gas.

Natural capital in economic income

Like we know, a capital yields income. Well, transferring this into ESS, natural capital yields natural income.

Did you know? The World Bank now calculates wealth or countries by including the rate of extraction of natural resources and the ecological damage caused by this.

Important fact: Sustainability often represens sources or conflict within and between political parties and counries.

Natural Income
Natural income, yields or harvests services. For example, water cycle provides fresh water and photosynthesis provides oxygen.

There are three main categories on natural income.

• Renewable: these are the resources that replace or restock themselves. They can include: water and lumber.
• Non-renewable: these are the ones that exist in finite amounts of Earth: These ones can include: minerals and fossil fuels.
• Replenishable: this category is for the resources that can be renewable but take really so long that can also be taken as non-renewable. More specific, is a mixture between both. An example of this can be grounwater.

However, we also have the fourth element, which is RECYCLABLE RESOURCES.

September 1 and 3 Notes

Here are some of the notes taken in class

Measuring changes in an ecosystem. Well first of all, it's necessary to remember some of the biotic and abiotic factors that exist.

• Abiotic: climate, soil, water, light.
• Biotic: biomass, productivity, biodiversity, NPP, GPP.

Now, EIA, stands for Environmental Impact Assesment. The name says it all, is an assesment that measures the impact, it can be beneficial or controversial, of certain project in a certain place. The EIA, may help us:

• Identify the impact
• Estimate or predict an impact
• Asseses and limits the impact

Furthermore, we saw a little bit of history on class. For example, we saw what NEPA was. NEPA stands for National Environmental Policy Act, which was an act that was of United States created in 1969, which later was adopted by others.

Measuring Biomass: Taiga

Here’s the biomass pyramid of a food chain located at the taiga. This was made the previous semester in our investigation of the taiga concerning many of their aspects.

Measuring Biomass

Before naming the different methods of measuring biomass, it is important to know what is biomass. Biomass or production is considered as the total weight of living organisms within a given area. This includes plants and animals. Biomass is usually expressed as g/ha, lbs/acre, or g/m².

Now, there are several methods for the measurement of biomass. Here are some of them.

• The most basic one is counting the specific number of organisms of the same species within a given area. However, this method can be inaccurate and difficult to accomplish.
• Some people use their perception to calculate biomass, especially on plants. A trained person could estimate the weight of a plant just by looking at it. The person may calculate the mass of certain plant, for example 5 grams. So, like in the example, when the specialized person looks at the same plant but more of them (such as two more), he or she could infer that the approximate biomass of that species in a given area is of 15 grams.

• Biomass could also be estimated by looking at the changes in time and the possible abiotic factors that could have interfered. Here’s an example of an analysis made during three years. Precipitation was measured and visual evidence was taken. In here, biomass could be estimated visually, since changes in biomass are clearly seen at the visual evidence.

• There’s also the direct or destructive method, which consists in cutting (in case of plants) a vegetation in a certain area and weighing its mass. Several samplings should be made in order to get accurate data. The grams per quadrat are converted to the corresponding measuremeny system.
• However, there are other methods that do not involve the direct experimentation with the species. This can be by taking scale digital images. Images are analyzed in the computer, calculations are made according to the information provided by the images (such as green pixels showing the biomass in the image) and models were made.

Evaluation of these methods

     Looking at each of these methods and analyzing them, I figured out that some have advantages and other ones disadvantages. Some of them such as estimating its mass, observing its changes, or counting them, may be a little inaccurate, but they are ways in which you aren’t harming species. Others, such as measuring its dry mass could be a little harmful since for example, in grass, the grass should be clipped off. It may be more accurate than others, but still it is a destructive method. Furthermore, there’s also the scanning of the species via digital photos, which measures digitally the species biomass. It’s a good method since it may be really accurate and it’s a non-destructive method. However, it may be a little expensive.

     So, looking and evaluating each of the methods, we can say that each one of them has their advantages and disadvantages. The thing is to revise each one of them and look at the one with the most advantages. In my opinion, I think that the best one is the one that uses scanned digital photos, since it’s really accurate and non-destructive. However, it may me expensive.

References

Tackenberg, Oliver. "A New Method for Non-destructive Measurement of Biomass, Growth Rates, Vertical Biomass Distribution and Dry Matter Content Based on Digital Image Analysis." Annals of botany. Oxford University Press, 12 March 2007. Web. 25 Aug 2010. <http://aob.oxfordjournals.org/cgi/content/full/mcm009v1>.

"Biomass Terminology ." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_1_Biomass%20Terminology.htm>.

"Direct Measures of Biomass ." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_3_Direct%20Methods.htm>.

"Estimating Biomass and Double Sampling ." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_4_Estimates%20Double%20Sampling.htm>.

"Why Measuring Biomass or Production?." University of idaho. College of natural resources, n.d. Web. 25 Aug 2010. <http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%206/6_2_Why%20Measure%20Biomass.htm>.

Measuring Biodiversity

It is important to take into account that when measuring biodiversity it is being tried to describe the relationship between individuals of varying subspecies within a zone. There are three most common ways of measuring biodiversity.

Species richness (S)

This is one of the most common ways. It Works by counting the subspecies diversity in a specific community. However, this method doesn’t indicate the proportion nor how the species are distributed or organized.

Simpson’s Index (D)

Simpson created this method in 1949, and it’s similar to the previous one. This one works by counting the subspecies (richness) and it also measures the proportion.

The first step to calculate the Index, is calculation Pi which is the abundance of a certain subspecies in a certain zone, divided by the total number of subspecies in the same zone.

Simpson's index: D

D = sum(Pi2)

This one calculates the probability of two randomly selected organisms in the zone, belong to the same species

Simpson’s Index of diversity: 1 – D

This one is the contrary of the previous one: the probability of two randomly selected organisms in the zone, do not belong to the same species.

Simpson’s reciprocal index: 1/D

The last one calculated the amount of equally common subspecies that will produce the observed Simpson’s index.

Like already said, Simpson’s index may be affected by the richness and the equitability of percent of each species present. When talking about the richness, D will decrease as the percentage of species is more equitable.

Shannon-Wiener Index (H)

The last one works with the number of individuals observed for each subspecies located in a sample plot.

This works similarly like the previous one. First, it is necessary to calculate Pi for each category of subspecies. Then, you need to multiply the logarithm of Pi base 10. Then the index is computed with a negative sum. Here is the formula:

H = -sum(Pilog[Pi]) 


Important fact: Knowing the Shannon-Wiener Index and species richness, it may be known the eveness. But, what is eveness? Eveness is the measure of how similar the abundances of different species are. When the evenness is one, it means that they have similar proportions. But when the abundance isn’t similar, the value tends to increase.

"Biodiversity Measures." Raytheon Employees Wildlife Habitat Committe. REWHC, 2000. Web. 18 Aug 2010. <http://www.rewhc.org/biomeasures.shtml>.

Classification of plants

Classifying living organisms is an important task. The most known method of classifying living things was created by Carolus Linnaeus. He introduced a hierarchy that classified living organisms from broadest to most specific. The hierarchy made by Carolus Linnaeus consists of several classifications: Kingdom, Phylum, Class, Order, Family, Genus, and Species. The following were ordered from the broadest classification, to the most specific classification. 

But there may be other classifications, probably not so known as the one of Linnaeus. The following chart shows one of the many classifications plants may have. This was found in a document/activity of Helen Saayman.

Saayman, Hellen. "To classify plants according to their characteristics." Connexions. The Connexions Project, 11 Mar 2010. Web. 11 Aug 2010. <http://cnx.org/content/m20135/latest/>.

Previous knowledge from the past semester

What is a system? A system is a set of components that function and interact in a predictable manner.

Ecosystems. There are several examples of ecosystems such as: Estuaries, swamps and marshes, tropical rain forest, temperate forest, savanna, agricultural land, shrubland, temperate grassland, lakes and streams, continental shelf, open ocean, tundra, desert scrub, and extreme desert.

Trophic levels. The term trophic level refers to the position it occupies a species in a food chain. An example of a trophic level may be:

Grass (as a producer) -- Grasshoppers (as primary consumer) -- Toads (as secondary consumers) -- Snakes (as tertiary consumers)

Taiga as an ecosystem. The taiga has a lot of different species. For example, canopy trees, which are producers, are eaten by primary consumers such as beavers. However, beavers are eaten by secondary consumers such as wolves. In here, we can see not only the different trophic levels, but the flow of energy via each individual. As well, we can see that in each consumption, some of the energy is lost as heat.