MEDCs vs LEDCs

MEDC	LEDC
The cost of sample food items are relatively cheap	Staple food items may not be always affordable as prices fluctuate
Most people make purchases based on taste and preference	People tend to make purchases based on nutritional need and affordability
Produce seasonality has mostly disappeared due to globalization	Political and economic agendas can affect food production
This has also allowed for a greater international variety in most supermarkets	Even if food crops are not used as cash crops, food production is still impacted since arable land
The average caloric content per capital per day of food is 3314 calories. In the USA specifically, this number is 3774 calories	In LEDCs the average caloric content per capital per day of food is 2666 calories. In Eritrea this number is 1512 calories

Food consumption

	MEDC	LEDC
Meat	12.9	7.3
Fish and Seafoods	1.4	0.9
Cereals	37.3	56.1
Vegetables, fruits, fats	48.4	35.7

The American Association for the Advancement of Science suggests that there is an average of 2790 calories available each day for every human on the planet. That is enough to feed everyone.

If food production has kept up with population growth, why are there still so many problems with famine, hunger and malnutrition?

Factors to consider

• Distribution:
• If countries like Canada, USA, and Australia have an excess to food, can that be shipped to Bangladesh, Ethiopia, or Sudan? Who will pay for it? Do they even want that kind of food?

• Politics
• If excess food is not paid for, is the receiving country in debt of the donating country

• So far, food supply has kept pace with human population growth, seemingly refuting Malthus… however recently some are doubting if this can continue

• As we adapt an increasing amount of global NPP to human needs. use and degrade more land, eat more meat, contaminate more water, we are getting closer to the planet's K... we just don't know that this is yet.

• There are 1.1 billion people living in poverty... They are increasing and growing hungrier.

Annual grain yields per hectare have slowed their rate of increase since the Green Revolution (1990-2000 had the lowest increase since before the 1950s).

Food Supply

Important Terms


Food security: This expression means that every person in a given area has a daily access to enough nutritious food to have an active and healthy life.
Food insecurity: The opposite of the first one. There are not enough food supply or simply people have not the needed resources to access them.

Undernutrution	Malnutrition	Overnutrition
Food consumed doesn't provide enough energy	Food has enpugh nergy but lacks nutrients, vitamins, proteins  and minerals	Food consumes has an excess of energy than the one needed and used

Basic Nutrients which cause malnutrition:

Vitamin A	Iodine	Iron
Blindness and children become prone to infection	Afects metabolism processes and causes stunted growth and may lead to goiter	Anemia, fatigue , risks of infection and increases risk for hemorrhage in labor.

Famine: A famine is a situation of severe shortage of food supply in an area accompanied by mass starvation, many deaths, economic chaos, and social disruption. 

Population Pyramids

Demographic Transition Model

• DTM describes the pattern of decline in mortality and natality (fertility) of a country due to social and economic development
• Can be described as a 5-stage model
• Pre-industrial
• LEDC
• Wealthier LEDC
• MEDC-stable
• MEDC-population decline

Environmental Economics

• How do we value resources
• Economic --> money
• Ecological --> support systems
• Scientific --> research
• Intrinsic --> cultural

• Natural capital
• Natural resources, services, and processes
• Natural income

• Types of natural capital
• Renewable
• Replace or restock themselves
• Non-renewable
• Exist in finite amounts on the planet
• Replenishable
• Between renewable and non-renewable
• Example Groundwater
• Recyclable
• Resources that can be transformed into usable materials after already being used for something else
• Iron, aluminum, etc

• Sustainability
• Living within the means of nature, on the "interest" or sustainable natural income generated by natural capital.
• However, economist and environmentalists may have very different views on what is sustainable
• Any society that supports itself in part by depleting essential forms of natural capital is unsustainable.

Population and Resource Use

• Population size is not the only factor that determines our species' impact on the environment
• Amount of wealth, including distribution
• Resource desire
• Resource need

• Many environmental impact models are based on the assumption that all individuals in a population have the same resource use and waste profile and thus impact the environment equally

Population Growth and Food Shortages

• Thomas Maltus was an English clergyman and economist who lived back in the day (1766-18434)

Population Size

• Four main factors that affect  population size
• Birth rate
• Death rate
• Immigration
• Emigration

• The measures of population change are
• Crude birth rate (CBR)
• 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 number of deaths per 1000 individuals in a population per year
• Calculated by dividing the number of deaths by the size of population and multiplied by 1000
• Doubling rate
• The time in years that it takes a population to double its size
• Doubling time = 70/NIR
• Natural increase rate
• NIR=(CBR-CDR) / 10
• This gives NIR on %
• Does not consider immigration or emigration
• Total Fertility Rate
• The average number of children that each woman has over her lifetime. It shows the potential for population change in a country.
• A TRF > 2.0 results in a population increase
• A TRF < 2.0 results in a population decrease
• A TRF = 2.0 results in a stable population

S and J Curves for Growth Rate

S-curves and J-curves

• S-curves
• Start with exponential growth
• Above a certain population size, the growth rate slows down until population stabilizes
• Consistent with density dependent limiting factors
• Population size stabilizes at the carrying capacity (K) of the environment
• The area between the exponential growth curve and the S.curve is called environmental resistance

• J-curve
• Shows a boom and bust pattern
• Population grows exponentially then crashes
• These collapses/crashes are called diebacks
• Population often exceeds K before the collapse occurs which is referred to as overshoot

Growth Rates

• S and J curves are idealized
• In nature both types of limiting factors act on the same population and the result is an S/J combo curve
• The growth rate of the human population is slowing as we reach the K of our environment
• Peaked at 2.1% per year in 1965-1970
• Now: 1.3% and falling
• Back in the day world population was increasing slowly due to environmental resistance, diseases, epidemics, famine, and natural catastrophes
• MEDCs and LEDCs
• Countries are also economically classified based in the industrial development or GDP
• MEDCs
• are industrialized nations with high GDPs
• Relatively rich population and starvation is unlikely
• High Level of resource use per capita
• Relatively low population growth rate
• LEDCs
• are less industrialized or have none at all
• May have plenty of natural capital but usually this is exported and processed in MEDCs
• Lower GDP and high poverty rates
• Large population sector with low standard of living
• High population growth rates

Population Dynamics

Populations change over time due to many factors/variable. These limiting factors may be classified as: Density dependent and Density independent.

Limiting factors:

• Density dependent
• Biotic factors
• Effects increase as population increases
• Act as negative feedback mechanisms, which function to regulate or stabilize a population size
• Internal Factors
• Act within a species
• Ex. Limited food supply, territory, density dependent fertility
• External factors
• Act between different species
• Ex. Predation and disease

• Density Independent
• In general tend to be abiotic
• Effects are not related with population growth
• Not part of a feedback system
• Weather, climate, volcanic eruptions, floods

Measuring Biodiversity

Biodiversity, according to the Convention of Biological Diversity, is: "the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and of ecosystems." Biodiversity is very important part of the environment since it helps it regulates the balance and the reusing and recycling of energy and materials within the ecosystem.

To study a certain area biodiversity needs to be measured. To measure biodiversity, we usually focus on 5 ways: Species richness, species evenness, disparity, species rarity, and genetic variability.

• Species richness: refers to the total number of members of a given species in a quantified area.

• Species Evenness: he degree to which the number of individual organisms are evenly divided between different species of the community.
• Disparity: measures the phenotypic differences among species resulting from the differences genes within a population.
• Species Rarity: the rarity of individual organisms within a quantified are.
• Genetic Variability: each population of species contributes to additional biodiversity due to variations between genes

There are other ways to measure biodiversity that combine richness and equitability. Most ecologist use the Shannon-Weiner or Information index:

that only means that you need to get the proportion of the specie to the whole and then multiply that number by its natural logarithm. 

For additional information go to:

http://www.denniskalma.com/biodiversitymeasurement.html for examples

The encyclopedia of earth: http://www.eoearth.org/article/biodiversity

Nature.com: http://www.nature.com/nature/journal/v405/n6783/full/405212a0.html

Classifying Organisms

Taxonomy
Taxonomy is the science of classifying organisms. Carol von Linne, mostly known as Carolus Linnaeus, was the Swedish botanist who began working on a system for the classification of organisms. This system evolved and became the most common system used today. The system consists of organizing different groups which are inside other groups. Each organism would be labeled with a species, related species would be organized in the same genus, similar genera would be in the same family, then families in an order, orders in a class, classes in a phylum (or a division), and phyla in a kingdom.

The Kingdoms, which are the largest groups, were only two in the beginning but have developed and now 6 Kindoms are usually accepted: Animalia, Plantae, Fungi, Protista, Monera, Archaea. 

• Kingdom Monera: Prokaryotes; Bacteria; May have fungus, plant, or animal characteristics; includes Eubacteria and Cyanobacteria; around 10,000 species
• Kingdom Archaea: Prokaryotes; always unicellular and living under rough or extreme conditions and environments; different chemical characteristics than Monera
• Kingdom Protista: Slime molds and algae; mostly unicellular; eukaryote; around 250,000 species
• Kingdom Fungi: Mushrooms, molds, mildew; multicellular; heterotrophic; almost never capable of movement; 100,000 species
• Kingdom Plantae: Multicellular and eukaryotes; producers of complex molecules using light (photosynthesis); 250,000 species
• Kingdom Animalia: Multicellular and eukaryotes; without cell walls which reduces stiffness; unable to produce food, need to take energy from external sources; 1,000,000 species (largest kingdom) 

A very important part of the classification are the homologous structures. Internal structures which may be similar to those of other organisms may help classify the groups. Characteristics such as reproduction methods, backbone existence, type of food consumed, body parts and covering, and others may also help in the grouping. There are other three ways of classifying including: systematics, cladistics, and molecular evolutionary taxonomy. Systematics and Cladistics use tree diagrams to explain relationships between organisms and find their way to a common ancestor. The difference between these two is that cladistics usually divide the branches when special traits are found. Molecular Evolutionary Taxonomy classifies by the presence of specific genetic changes in organisms. Still the anatomical classification (Linnaeus method) is the most common. It keeps changing because of the new discoveries available because of new technology.

A common example of Linnaeus's method are humans:

• Kingdom: Animalia
• Phylum: Chordata
• Class: Mammalia
• Order: Primata
• Family: Hominidae
• Genus: Homo
• Species: sapiens sapiens

A species is the one who breed exclusively inside a group and produces fertile offspring. The name of the species would be used with the genus name in the binomial nomenclature to make up the official name of a certain organism. In the past example the species's name would be Homo sapiens sapiens.

Reviewing Concepts

What is a system?
A system is a group of interrelated elements that work together and form a unified whole. They can be closed, open or isolated.


Types of Ecosystems
There are many different ecosystems ranging from aquatic to terrestrial. Some of them include: the Tundra, Taiga, Savanna, Tropical Rain Forest, Desert, Desert Shrub, Deep Ocean, Estuaries, Template Forests, etc. Each of these types is different in temperature, rain fall, fauna, flora, latitude, altitude, and many other elements. 


Trophic Levels
Trophic levels are the position of an organism in a food change. Starting with producers, which make up the first level, to herbivores, second level also called primary consumers, to carnivores which make up the rest of the levels, usually secondary or tertiary consumers depending on the level. Not every food chain has the same number of levels, it depends on the amount of organisms which participate in it. 


Example:
1st level: Grass (producer) ---> 2nd level: Snowshoe Hare (primary consumer)---> 3rd level: Lynx (secondary consumer)


THE TAIGA!
The taiga is an ecosystem located in northern latitudes beneath the tundra. It is usually found in Canada, Russia, Sweden, Finland, Norway and the extreme northern parts of the United States. In this ecosystem temperatures range from -54°C to 30°C throughout the year. Snow and ice usually appear in winter, which occurs most of the year since summer is really short. During summer the air is humid which allows vegetation to grow, but in general there is a very small amount of precipitation and winters are very dry. Vegetation in the lower parts include a large amount of trees and mos but in higher parts trees are sparse and lichens are more common. Animals include the snowshoe hare, lynx, wolfs, bears, moose, deer, owls, eagles, raccoons, etc. 
The trees and small lichens that live in the taiga are the producers of most of the energy that is used in the taiga. There are lots of different omnivores and herbivores which eat these plants and store the energy so carnivores can take it. The matter flow is generally moderated by decomposer organisms like fungi and bacteria. Decaying bodies from plants and animals are broken down by them so that matter is recycled. During winter both energy and matter flow decreases because of the migration of many of the species to other warmer places. 

And it Begins!

Hi! My name is Sofía and I'm an IB student in Monterrey, Mexico. Today my teacher asked us to create a blog in which we would include all the evidence will be gathering and learing during the course. I'm not really sure how it will work, but I'm very excited!