1. Unit 2 ecosystems

2. What is an ecosystem?
An ecosystems is a group of living things and non- living things that live in the same area. All elements of an ecosystem interact. Species: a group of organisms that can reproduce with other individuals and produce fertile offspring (descendencia). A population is made up (está compuesta) of all the individuals that belong (pertenecen) to the same species in an area. A community: a group of different populations that live together.

3. HOW LIVING THINGS INTERACT IN AN ECOSYSTEM
Producers: plants that take nutrients from the soil and energy from the sun and make their food by photosynthesis.
Consumers:
Primary consumers that eat producers are called herbivores.
Secondary consumers that eat other consumers are called carnivores.
Tertiary consumers that eat both producers and consumers are called omnivores.
Decomposers: bacteria and fungi that feed off (se alimentan de) the remains of dead animals and plants. They return the nutrients to the soil so plants can use them.

4. The balance of living things
Living things in an ecosystem eat each other and this is how (así es como) the energy passes from one living thing to another. If we draw a line between eaters (los que comen), we have a food chain. Each of these organism is a link in the food chain. In an ecosystem, most living things are part of several food chains, we have a food web. In an ecosystem, if the population of one group changes, this affects the population of other groups. And as a result, this modifies the ecological balance.

5. Terrestrial ecosystem
Cold deserts
Taiga
Temperate forests
Warm deserts
Savannahs
Rainforests and jungles
Example
Antarctica
North of Europe
Canada
Sahara
Africa
Amazon
Temperature
Freezing
Cold
Cold in winter and mild (suave) in summer
High during the day and cool at night
High all year
High
Precipitacion
Little (poco)
snowy in winter, rainy in summer
Rain is moderate
Scarce (escasa)
Wet (húmeda) season and dry (seca) season
Rains all year
Vegetation
Little
Evergreen tree (perenne)
Deciduous trees (caduca)
little
Grass and bushes (hierba y arbustos)
abundant
Animals
Thick layer of fat
Herbivores and carnivores
Often migrate in winter
Animals can live without water
Wide variety (amplia variedad)
Many

6. AQUATIC ECOSYSTEMS Aquatic ecosystems can be:
Marine ecosystems are oceans and seas.
Freshwater ecosystems are lakes, ponds (estanques), rivers and streams (arroyos).
Living things in marine ecosystems can be producers (phytoplankton carry out (llevan a cabo) photosynthesis), consumers (fish, marine mammals...) and decomposers (fungi and bacteria that transform final remains of dead organism into nutrients for producers).
Distribution of life in marine ecosystems:
- Coastal zone is near the surface (superficie). Light enters the water. There are producers. Most fish and marine mammals live there.
- The middle zone: little light. Plants dont live there but many fish do.
- The deepest zone: no sunlight.

7. How human beings change the environment (medio ambiente)
If we don’t control human activity:
Many species of plants and animals will become extinct (se extinguirán)
Natural resoirces (recursos) will disappear.
Air and water will be polluted (contaminado)
The solution is to reduce the negative effects.
There are many actions that have a positive effect on the planet:
Repopulate (repoblar) the forests
Reuse and recycle (reciclar) materials
Water purification