lunes, 22 de mayo de 2017

7 Billion: How Did We Get So Big So Fast?

It was just over two centuries ago that the global population was 1 billion — in 1804. But better medicine and improved agriculture resulted in higher life expectancy for children, dramatically increasing the world population, especially in the West.

As higher standards of living and better health care are reaching more parts of the world, the rates of fertility — and population growth — have started to slow down, though the population will continue to grow for the foreseeable future.

El equilibrio del mundo (Documentos TV - La 2 de RTVE)

serie de 5 videos


domingo, 16 de abril de 2017


Territorial organization
After the Constitution, Spain is divided into 17 Autonomous Communities, 50 provinces and two Autonomous Cities: Ceuta and Melilla.

domingo, 19 de marzo de 2017


There are six major zones of vegetation on the island, according to altitude and directional aspect.

1) and 2) Sea level and Coastal scrub (Lower Xerophytic Zone)
from 0 to 50 m. and from 50 to  300m. A xerophyte is a plant adapted for growth under dry conditions. This area of Tenerife is ideal for them. Examples include spurges, cactus spurge and wax plants...

3) Thermophile Forests
300 - 500 m (northern slope) and 300 - 1000 m (southern slope). A "thermophile" is described as an organism that thrives at a temperature of 50° or higher. This is an area of moderate temperatures and rainfall and has been adversely affected by human activity. It contains many endemic species such as juniper, palm trees and the famous dragon trees....

4) Laurel Forest (Monteverde or Laurisilva)
500 - 1500 m. (northern slope)
This is a zone characterised by frequent rainfall and mist (laurisilva forest). Many large trees, with abundant undergrowth of bushes, herbaceous plants and ferns. Plants such as laurels, holly..

5) Pine Forest
1000 - 2000 m.
Open pine forest, with thin, unvaried undergrowth. Examples of Canary Island pine, broom and rock rose.

6) High Mountain scrubland
Over 2000 m. (only in Tenerife, La Palma and Gran Canaria)
Dry climate, strong sunlight and extremes of day and night temperatures. Flora well adapted to the conditions. Many endemic species here. An area of great scientific importance. Examples of endemic flora include Vipers bugloss, Teide white broom and Teide violet.

Los pisos de vegetación de las Islas Canarias