The
Biosphere
v The biosphere
consists of all organisms on Earth together with the physical environments in
which they live. This is where ecological interactions take place.
o
Ecology:
study of interactions between organisms and their environment that take place
within the biosphere
o
Why do
you think understanding ecology is important?
v The biosphere is
an interconnected web. Visit the following website: http://www.nt.gov.au/nreta/wildlife/animals/native/dingo.html
and answer the following questions.
o
Ex:
dingoes in Australia
§ What is a dingo?
§ When and how were dingoes introduced to
Australia?
§ Why have wild dog control measures been
less intensive in the Northern Territory?
§ How have dingoes negatively affected their
environment?
§ What are the advantages of leaving dingoes
in their environment?
v Climate affects
the biosphere, but what factors contribute to climate?
o
Incoming solar
radiation shapes climate. More sunlight reaches Earth’s surface near the
tropics than near the poles: in fact, tropical regions receive 2.5 times the
solar radiation than polar regions. There are less
seasonal fluctuations in temperature, resulting in a warm, stable climate
throughout year. Visit the following website to answer the following questions:
http://earthobservatory.nasa.gov/Features/SORCE/sorce_02.php
§ What is thermal radiation?
§ How much Total Solar Irradiance is taken
in by Earth’s land and oceans?
o
Global movements
of air and water shape climate.
§ Air: Near the equator, sun heats moist air,
causing air to rise from surface of Earth.
Warm hair rises because heat causes it to expand and be less dense than
air that has not been heated. Warm,
moist air cools as it rises. As a
result, rain falls because cool air cannot hold as much water as warm air can. Usually, cool air sinks. However, cool air above equator cannot
immediately sink because of warm air rising beneath it. Instead, cool air moves to north and south,
tending to sink back to Earth at 30 degrees latitude. Cool air warms as it
descends, allowing it to hold more water.
As air flows back toward the equator, it absorbs moisture from the
Earth’s surface. By the time it reaches the equator, the air is once more warm
and moist, so it rises, repeating the cycle.
§ Convection cells:
where warm moist air rises and cool, dry air sinks: two are found in tropical
regions and two in polar regions where they generate
consistent wind patterns. No stable
convection cells in temperate regions (30-60 deg lat), this results in more
variable winds that form when cool, dry air from polar
regions collides with warm, moist air moving north from tropics.
§ Prevailing winds:
easterlies and westerlies. Winds curve as they travel since the Earth
rotates. Winds traveling toward the equator blow in from east, and winds
traveling toward the poles blow in from the west. Since these are generally
consistent, there are known as prevailing winds. In US, storms generally move from west to
east.
§ Where did the term “down in the doldrums”
came from?
§ Find or draw an image of the Earth’s
prevailing winds and place it below.
§ Water: Ocean currents are produced by
rotation of Earth, differences in water temp between the poles and tropics, and
directions of prevailing winds. In the Northern Hemisphere, currents tend to
run clockwise between continents and counterclockwise in the Southern Hemisphere.
Ocean currents carry huge amounts of water and can have a great influence on
regional climates. Gulf Stream moves 25 times the amount of water carried by
all the world’s rivers combined. Without warming effect of water carried by this
current, the climate in Great Britain would be subarctic to arctic instead of
temperate.
o
Major features
of the Earth’s surface shape climate. Oceans and lakes moderate the climate
of surrounding lands. In addition, mountains often cause a rain shadow effect,
in which little precipitation falls on the side of the mountain that faces away
from the prevailing winds. This can
contribute to formation of deserts. Ex: Sierra Nevada
v Biosphere can be
divided into biomes = major
terrestrial and aquatic zones of life and are usually named after the dominant
vegetation of the region. Describe the characteristics that distinguish each of the following
biomes from each other. Also include
where these biomes are typically located.
o
Tropical
forest
o
Temperate
forest
o
Grassland
o
Chaparral
o
Desert
o
Boreal
forest
o
Tundra
v Aquatic biomes: usually
characterized by physical conditions of the environment. Define each of the following terms:
o
River
o
Lake
o
Wetland
o
Estuary
o
Intertidal
zone
o
Coral
reef
o
Open
ocean
o
Benthic
zone
v Human Impact on
Biosphere: ex=Laurel wilt
o
What
is laurel wilt?
o
How
was laurel wilt spread in red bay trees throughout the southeast?