Download GEOSPHERE The geosphere is the Earth itself, the rocks, minerals

GEOSPHERE
The geosphere is the Earth itself, the rocks, minerals, and landforms of the surface as well as its
interior. Below the crust, which varies from about 5 km beneath the ocean floor to up to 70 km
below the land surface, temperatures are high enough for deformation and a paste-like flow. At
one time, roughly 200 million years ago, the continents were joined together in a supercontinent
called Pangaea, but since then the tectonic plates have slowly separated, creating the
arrangement of the continents we are accustomed to today.
Plate tectonics is ongoing and humans can witness its sometimes violent activity in the form of
earthquakes and volcanoes. More regularly, however, human interaction with the dynamic
geosphere comes in the form of surface erosion, our use of arable land for farming, and
excavations for the construction of buildings, roads, and mines.
Aside from surface disturbances such as excavations and agriculture, humans have a fairly minor
impact on the workings and scale of the geosphere. Humans still live largely at the mercy of
powerful geologic forces. The 2010 Haiti earthquake is just one of many examples of the
devastating impact of these forces. While we may never be able to stop earthquakes or
volcanoes, our understanding of their mechanics may enable us to better understand their
dynamics and possibly develop means for reducing human risk from their occurrences.
Additionally, advances in geothermal technology will enable us to harness greater amounts of
heat energy within the crust, which can be converted to electricity at the surface.
BIOSPHERE
The biosphere –the sphere of life – was named by Eduard Suess in 1875 but not fully described
as a concept until the work of Vladimir Vernadsky in the 1920s. The biosphere is made up of
biomes, or biophysical zones, filled with many ecosystems each composed of an intricate set of
species adapted to the prevailing conditions from below ocean floors and the land surface to
above the highest mountains. It includes life forms ranging in size from microscopic bacteria to
the gargantuan blue whale. While persistent for billions of years, the biosphere has been hit by
five mass extinctions in the geologic past and now faces existential threats to species diversity
from human activity.
How does the biosphere work?
Throughout the evolution of life on Earth, from primitive organisms to the present set, all life
forms have found ways to obtain energy, acquire nutrients to build organic molecules, and
reproduce. Energy from the sun is captured by photosynthesizing organisms called autotrophs, or
producers, that can harness solar energy to convert inorganic molecules into organic molecules -the building blocks of life. These organic molecules store energy and are consumed by other
non-photosynthetic organisms called heterotrophs, or consumers. This seemingly simple process
-- grass being eaten by deer, for example -- took billions of years to develop. Through the
process of evolution, species diversify to fill the available opportunities for existence, creating an
ever changing set of plants and animals found in the Earth’s biomes from tundra to rainforests.
The anthroposphere
The anthroposphere encompasses the total human presence throughout the Earth system
including our culture, technology, built environment, and activities associated with these. The
anthroposphere complements the term anthropocene – the age within which the anthroposphere
developed. Some mark this with the advent of agriculture, others with the industrial revolution.
In physical terms, the anthroposphere is comprised of the cities, villages, energy and
transportation networks, farms, mines, ports, as well as the books, software, blueprints, and
communication systems – the mark of civilization.
Using a broad definition of the anthroposphere, it extends beyond Earth. For example, our radio
and television broadcasts of the 20th and 21st centuries travel at the speed of light as an
expanding electromagnetic sphere of human origin into the Milky Way galaxy. Another, more
tangible, example are the four NASA probes, Voyagers 1 and 2 and Pioneers 10 and 11,
launched in the 1970s and now venturing beyond our Solar System. In the event of an encounter
with any other intelligent life, each probe contains images and other artifacts that attempt to
convey the basic characteristics of humans and their niche within the universe.
When compared with most natural changes in other spheres, change in the anthroposphere is
happening rapidly. This is partly due to the rapid increase in population over the past several
centuries but also as a result of the strides in technology and energy that have empowered
humans to directly and indirectly effect change to the environment. In terms of world population,
the number of humans has soared from about 1 billion in 1800 to nearly 7 billion today.
To make room and to feed these added billions, the anthroposphere has expanded to occupy
more land for dwellings and agriculture. In addition, human appropriation of fossil fuel energy
and the many technologies it powers have played a major role in amplifying the influence of the
anthroposphere in the Earth system. It has enabled humans to cut deep holes into the Earth to
extract resources such as iron ore and bauxite, which are used to make up the automobiles,
skyscrapers, and countless gadgets integral to modern life. However, these activities have
expanded the anthroposphere in subtle ways by infusing pollutants into our water and air,
negatively affecting the biosphere and bringing about global warming.
What is the hydrosphere?
The hydrosphere is the sum of all water on Earth and the water cycle that distributes it around the
planet. Earth is unique in the solar system for its abundant surface waters. Our orbital distance
from the sun, in addition to our unique atmosphere, gives Earth the right temperature in our
middle-aged solar system to have water as a liquid, lots of it. Venus is too hot, Mars too cold.
Earth is just right. Noted astronomer Carl Sagan described Earth as seen from distant space as a
"pale blue dot," signaling our planet as an outpost of life. It's because of the hydrosphere that life
flourishes on Earth.
Just as important as the existence of water is the hydrologic cycle (animation) that moves water
around the globe. Driven by solar energy, surface waters evaporate into the atmosphere,
condense, and fall back to the surface as precipitation, shaping continents, creating rivers, and
filling lakes. This process erodes billions of tons of surface material from the continents to the
oceans, forming the major river deltas. By far, most of the hydrosphere is salt water, some 97
percent, but the 3 percent that is fresh is critical for terrestrial and fresh water species.
FAUNA AND FLORA
Fauna is all of the animal life of any particular region or time. The corresponding term
for plants is flora. Flora, fauna and other forms of life such as fungi are collectively referred to
as biota.