martes, 16 de noviembre de 2010

Summary: How Ecosystem Change

How does abandoned farmland become a forest?

Abandoned Farm - First Year.  A comumunity of crabgrass, insects and mice invades the field where corn or another crop once grew.

Second and Third Years. Tall weeds,such as asters, ragweed, and goldenrod, and tall grasses grow among the crabgrass.  The crabgrass can´t easily survive in the shade cast by the taller weeds.  It begins to die out.  Rabbits and seed-eating birds move in.

Four to Six Years Later.  The hot, dry field of tall weeds provides a perfect environment for pine seeds to sprout.  Pine trees begin to grow and shade the weeds, which begin to die out.  More birds join the community, as do small mammals like oposssums and skunks.

Twenty-Five Years Later. A pine forest has replaced the old farm field.  Yet the number of new pine seedlings drops bacause they can´t grow in the shade.  Seeds of deciduous trees such as maple, hickory, and oak sprout and take root.  Larger animals like raccoons and foxes begin to visit.

One Humdred Years Later. The forest now mostly deciduous trees.  These trees are the habitats of many different kinds of birds and small animals, such as squirrels.  Deer, raccoons, and foxes also live in the forest.

Summary: Places to Live Arround the World

A Biome is an ecosystem to live. The land biomes are:

Taiga is the world's largest terrestrial biome and covers: in North America most of inland Canada and Alaska.
The summers, while short, are generally warm and humid. In much of the taiga, -20 °C would be a typical winter day temperature and 18 °C an average summer day.

Tundra:Arctic tundra contains areas of stark landscape and is frozen for much of the year. The soil there is frozen from 25–90 cm (9–35 inches) down.

Desert:Many deserts are formed by rain shadows; mountains blocking the path of precipitation to the desert (on the lee side of the mountain). Deserts are often composed of Sand and rocky surfaces

Deciduous Forest:
The temperate deciduous forest has a temperate climate, with summer highs of around 80 to 90 degrees Fahrenheit (27 to 32 degrees Celsius).

Tropical Rainforest: Commonly known as tropical rainforest, are forests which receive high rainfall (more than 2000 mm, or 80 inches, annually) throughout the year.

Some acuatic Biomes are:

Salt water: Plankton: organisms that float in the water.
Nekton: are organisms that swim through the water.
Benthos: bottom dwelling organism.

Fresh water:Plankton: organisms that float in the water.
Nekton: are organisms that swim through the water.
Benthos: bottom dwelling organism.