Lista de ponencias

PONENCIAS

1. El caso de Marina Isla de Valdecañas y Paca Blanco. Otro ejemplo del riesgo de proteger el medio ambiente 

2. ¿Qué es desarrollo sostenible? El origen del concepto. Ejemplos de éxito de desarrollo sostenible. 

3. Querido Sr Presidente (carta pidiendo solución a los problemas ambientales y a la pérdida de biodiversidad) 

4. ¿Por qué están desapareciendo las abejas? ¿Cuáles son las consecuencias?

5. La importancia de caballos, vacas, ovejas y cabras en la conquista europea del nuevo mundo. ¿Por qué no existían estos animales en América durante la época de la invasión española 

6. ¿Venimos del mono? Si no, ¿De dónde venimos? Breve historia evolutiva de la especie humana. 

7. Posiblemente el descubrimiento de la estructura del ADN ha sido el descubrimiento más importante de la Biología del s XX (Nobel, 1953). ¿Cuál es la estructura del ADN y por qué es tan importante?

8. El origen de las células eucariotas. Hipótesis endosimbionte de Lynn Margulis. ¿Por qué los seres multicelulares son todos eucariotas?

Calcium in our bodies

Tips for saving water at home

Plate tectonics summary

PLATE TECTONICS SUMMARY

The Earth's crust is broken up into pieces called plates. Heat rising and falling inside the mantle creates convection currents generated by radioactive decay in the core. The convection currents move the plates. Where convection currents diverge near the Earth's crust, plates move apart. Where convection currents converge, plates move towards each other. The movement of the plates, and the activity inside the Earth, is called plate tectonics.

Plate tectonics cause earthquakes and volcanoes. The point where two plates meet is called a plate boundary. Earthquakes and volcanoes are most likely to occur either on or near plate boundaries.

The Earth's plates move in different directions.

Different plate boundaries

• At a tensional, constructive or divergent boundary the plates move apart. As the plates move apart (very slowly), magma rises from the mantle and erupts to the surface of the Earth, normally accompanied by earthquakes. When the magma reaches the surface, it cools and solidifies to form a new crust of igneous rock. This process is repeated many times, over a long period of time. Eventually the new rock builds up to form a volcano.

Constructive boundaries tend to be found under the sea, eg the Mid Atlantic Ridge. Here, chains of underwater volcanoes have formed along the plate boundary. One of these volcanoes may become so large that it erupts out of the sea to form a volcanic island.

• At a compressional, destructive or convergent boundary the plates move towards each other. This usually involves a continental plate and an oceanic plate. The oceanic plate is denser than the continental plate so, as they move together, the oceanic plate is forced underneath the continental plate. The point at which this happens is called the subduction zone. As the oceanic plate is forced below the continental plate it melts to form magma and earthquakes are triggered. The magma collects to form a magma chamber. This magma then rises up through cracks in the continental crust. As pressure builds up, a volcanic eruption may occur.
• At a conservative or transform boundary the plates slide past each other.