miércoles, 8 de marzo de 2017


5º . Unit 6.          Biosphere.
 The biosphere is defined as the sphere or area around the planet Earth where life exists. This zone of life is vast. Most lifeforms live on or near the surface of Earth. However, some live deep within the hydrosphere (oceans, lakes and streams), while others thrive in the depths of the lithosphere (solid portion of Earth). For this reason, mapping the exact borders of the biosphere is quite challenging.
The biosphere is all about life. Physical geographers use the term biosphere to describe our living world. All of the microbes, plants, and animals can be found somewhere in the biosphere. The biosphere extends to the upper areas of the atmosphere where birds and insects can be found. It also reaches to dark caves deep in the ground or to the bottom of the ocean at hydrothermal vents. The biosphere extends to any place that life of any kind might exist.



Food Chain

Food Chain

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Every living plant and animal must have energy to survive. Plants rely on the soil, water, and the sun for energy. Animals rely on plants as well as other animals for energy. In an ecosystem, plants and animals all rely on each other to live. Scientists sometimes describe this dependence using a food chain or a food web. Food Chain A food chain describes how different organisms eat each other, starting out with a plant and ending with an animal. For example, you could write the food chain for a lion like this: grass ---> zebra ---> lion The lion eats the zebra, which eats the grass.

 The Food Chain
Every living thing needs energy in order to live. Everytime animals do something (run, jump) they use energy to do so.

Animals get energy from the food they eat, and all living things get energy from food. Plants use sunlight, water and nutrients to get energy (in a process called photosynthesis). Energy is necessary for living beings to grow.
A food chain shows how each living thing gets food, and how nutrients and energy are passed from creature to creature. Food chains begin with plant-life, and end with animal-life. Some animals eat plants, some animals eat other animals.



Loss of Biodiversity

The main cause of the loss of biodiversity can be attributed to the influence of human beings on the world’s ecosystem, In fact human beings have deeply altered the environment, and have modified the territory, exploiting the species directly, for example by fishing and hunting, changing the biogeochemical cycles and transferring species from one area to another of the Planet. The threats to biodiversity can be summarized in the following main points:
  • Alteration and loss of the habitats
  • Introduction of exotic species and genetically modified organisms
  • Pollution
  • Climate change
  • Overexploitation of resources