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Food Food Food :D

Food Security is the term that refers to the situation in which every person in a given area has daily access to enough nutritious food to have an active and healthy life. Developing countries do not produce enough food for feeding their people and are too poor to import enough food to provide national food security. Food security also depends on gently reducing the harmful environment effects of agriculture, not only at local, but also at national and global levels.
In order to maintain good health, the human body needs macronutrients, micronutrients and minerals. 

When people cannot grow or buy enough food to meet their basic needs, they suffer from chronic undernutrition or hunger. Children who suffer undernutrition often live in developing countries. The consequences of this are mental retardation, stunted growth and death caused by infectious diseases such as measles and diarrhea.

Malnutrition results from deficiencies of protein, calories and other key nutrients. This is because many of the world’s poor can afford only to live on a low-protein, high-carbohydrate, vegetarian diet. Overnutrition occurs when food energy intake exceeds energy use and causes excess body fat. Too many calories, too many exercise or both can cause overnutrition.

One of every three people has a deficiency of one or more vitamins and minerals, especially vitamin A, iron and iodine. Iron, is a component of the hemoglobin that transports oxygen in the blood. Too little iron, may cause fatigue, makes infection more likely and increases a woman’s chances of dying from hemorrhage in childbirth. It also causes anemia.
A famine occurs when there is a severe shortage of food in an area accompanied by mass starvation, many deaths, economic chaos, and social disruption. Famines often lead to mass migration of starving people to other areas or to refugee camps in a frantic search food, water and medical help. Famines are usually caused by crop failures from drought, flooding, war and other catastrophic events.

There are three main systems which provide most of the world’s food:
    • Croplands: Mostly produce grains, and provides 77% if the world’s food using 11% of the world’s land area.
    • Rangelands and pastures: produce meat, mostly from grazing livestock and supply about 16% of the world’s food using about 29% the world’s land area.
    • Oceanic fisheries: Supply about 7% of the world’s food.
Traditional agriculture consists of two main types which together are practiced by the 42% of the world’s people and provides one-fifth of the world’s food supply:
  • Traditional Subsistence Agriculture: Uses mostly human labor and draft animals to produce only enough crops or livestock for a farm’s family survival.
  • Traditional Intensive Agriculture: Farmers increase their inputs of human and draft-animal labor, fertilizer and water to obtain a higher yield per area of cultivated land. They produce enough food to feed their families and to sell.

Population Pyramids :D

There are different types of Pyramid Shapes:


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.


LECD tend to be stage 1 or 2, while MEDC are in stages 3 or 4.



Sustainable Yields :D

Sustainable Yield: natural income that can be exploited each year without depleting the original stock or affecting its potential for replenishment.


There are several concepts involved when calculating the sustainable yield of an ecosystem, such as the carring capacity (K), the population size , and  biomass of the ecosystem. 


In order to calculate the Sustainable Yield, the following formulas should be applied:


SY= Annual Growth and Recruitment - Annual Death and Emigration


This formula measures the inputs and outputs that an ecosystem has, by considering the number of individuals that enter or are born in the ecosystem minus the number of individuals that leave or die.


Another formula used by measuring the sustainable yield available in an ecosystem is:


SY= (Total Biomass or energy at a Time T)+1 - (Total Biomass or energy at a Time T)


This formula consideres the change in biomass in an ecosystem between a period of time.



Economy... Systems... Economic Systems :O

An economic system is a system that distributes goods and services by using different types of resources. The main objective of economic systems is to satisfy people's needs and wants in the must effective and efficient way.   Economic systems, as any other system, requires an input (in this case resources) and has an output (which means the goods and services)

The resources used by an economic system, can be classified into 3 different categories:

  • Natural Capital
  • Human Capital
  • Manufactured Capital
Natural resources, which are the ones provided by Natural Capital, are classified in the following categories:
  • Renewable
  • Non renewable
  • Replenishable
  • Recyclable

Sustainability :P

Sustainability is a word that is being very used lately by everyone. We find this word in many places, such as TV,  Newspapers, radio, etc. but we don't really know its meaning. So how can we define it? Why is this word so important for us?

Sustainability involves many concepts that lead to taking care of what we have and making it work, but always taking care of the impact that our actions have and trying to do the best, not only for us, but for everything around us. Sustainability, also involves many actions that we as humans can perform in order to take care of our planet, such as using only the resources we need, being responsible with this usage, taking care of nature and environment and educating everyone else in all the actions they can do in order to have a sustainable life or being a sustainable person :)

Biomass!!! :D

What is biomass? Why is it important?
Biomass is the ammount of organisms living in a certain area. Biomass can be measured for knowing the state of an acosystem, since it studies the ammount of energy available in an ecosystem. This will be useful, because by knowing the energy present in the ecosystem, we can know how many species will be able to live in there. 

How to measure Biomass?
There are several ways for measuring biomass, each of them has advantages and disadvantages in the process and results given:

  • Obtaining the weight of an organism and multiply it times the ammount of organisims living in the area. The units are grams per meter squared. The disadvantage of this method is that it is difficult to know accurately the number of organisms of each specie, which in case of error, will highly modify the result of the measurement.
  • Transect method, consists on tracing an imaginary line across the selected ecosystem, and counting the organisms that are in the quadrants following the transect.
  • Quadrant method, is another method for measuring biomass in which an area is determined and  biomass is measured by applying other methods but only in the specified area.
 What about an estuary?
After biomass is collected at different trophic levels, a biomass pyramid can be made. Here's an example of an estuary, more specifically, Chesapeake Bay. Taking the following food chain:

phytoplankton -> clams -> blue crabs -> sandbar sharks

Firstly, the units will be measured in kg per cubic kilometer, since it is a aquatic ecosystem. We can calculate the amount of each species in the food chain, and we get the following information:

There are 31,333,333 units of phytoplankton in 2320 cubic km of water in Chesapeake Bay.
There are 9,200,000 clams in that same area.
There are 278,666 blue crabs.
There is one sandbar shark.

Then, considering the weight of each specie and the area, we can calculate biomass, which then can be shown in what is known as a biomass pyramid.

Biodiversity :D

Biodiversity is defined as the variety of all forms of life, from genes to species, through to the broad scale of ecosystems.  

Biological diversity can be quantified in many different ways. The two main factors taken into account when measuring diversity are richness and evenness. Richness is a measure of the number of different kinds of organisms present in a particular area. For example, species richness is the number of different species present. However, diversity depends not only on richness, but also on evenness. Evenness compares the similarity of the population size of each of the species present.

 A diversity index is a statistic  intended to measure the differences among members of an ecosystem consisting of various types of objects. There are different types of diversity indexes such as:
  • Simpson's Diversity Index: measures the probability that two individuals randomly selected from a sample will belong to the same species. It is measured by the following formula:
When apllying the formula, the value that we can obtain starts with 1, representing a community of only one specie. The higher the value obtained, represent greater diversity.

To calculate Simpson's Index for a particular area, the area must first be sampled. The number of individuals of each species present in the samples must be noted. 
  • Shannon's Diversity Index: Is another diversity index used for characterize diversity in a community. It accounts for both abundance and evenness of the species present. The formula for applying this index is:

  • Berger-Parker Diversity Index: Number of individuals in the dominant taxon relative to n










Organizing Organisms...

Because of the enormous amount of species in our planet, it is neccesary to classify them using a logical order. The most used system for achieving this organization, is the binomial nomenclature. This system was developed by Carolus Linnaeus. There are seven classification levels:
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genum
  • Species
In the generally accepted system there are 5 kingdoms:
  • Animalia
  • Plantae
  • Fungi
  • Protista
  • Monera
Dichotomous Key is a method of organizing organisms based on characteristics. Organisms paired  with a series of direction that leads to increrasingly more specific descriptions of an organism, ending when a group containing all of the relevant characteristics found.

Estuary :D

An estuary is a semi-enclosed body of water found between rivers and oceans. It is where saltwaters meets freshwater. Because of the several amount of species living on this ecosystem, we can find lots of flows, storages, sinks and transformations of energy. An example of this could be seen in both pyramids presented below.

Thie yellow pyramid shows the biomass existing on a foodchain of the Estuary, and how it decreases as the trophic level increase.  In the green pyramid we can appreciate how in the same food chain the energy is passed and lost trough trophic levels.

Trophic Levels**

A trophic level is the hierarchal position that an organism or group or organisms occupies in an ecosystem. 3 levels can be mainly found in an ecosystem:

  • Producers: An organism that obtains organic food molecules without eating other organisms but by using energy from the sun or inorganic molecules to make organic molecules.
  • Consumers: An organism that obtains its nutrition by eating other organisms. Herbivores and Carnivores. The role of consumers in an ecosystem is to transfer energy from one trophic level to the next. In this trophic level, we can find several sublevels in which species can be classified into: primary, secondary tertiary and quaternary consumers.
  • Decomposers: An organism that obtains energy by breaking down dead organic matter into more simple substances. Alco called saprobes.

Ecosystems!

Ecosystems are complex sets of relationships among the living resources, habitats and residents of an area. Ecosystems consist of nonliving (Abiotic) and living (Biotic) components and are often described based on feeding relationships. Some examples of ecosystems are:
  • Desert
  • Forest
  • Coral Reef
  • Tundra
  • Savanna
  • Chaparral
Each of these ecosystems, are located in different parts of the planet and share characteristics such as weather, vegetation, species, etc. which allows us ti classify them into these categories.


Systems :)

System is a word used to define a set of components which interact and function between them. One of the main characteristics of a system is that it acts in a predictable way and is composed by:
  • Inputs
  • Outputs
  • Flows
  • Storages
  • Sources
  • Sinks
 Systems can be classified into 3 different categories:
  •  Open System: Materials and Energy are exchanged across the boundaries of the system.
  •  Closed  System: Energy is exchanged across the boundaries but matter is not
  •   Isolated System: Neither matter nor energy is exchanged.

Welcome!

Hello  :)
Welcome to my ES&S Blog, in here you will find updates about everything I learn in my Environmental Systems and Societies IB Course. I hope you find it interesting and useful, because in here we got some important stuff everyone of us should know in order to respect the world where we live and understand the impacts that our actions have. Thanks for visiting and wish you find this useful.