ENVIRONMENTAL SCIENCE CHAPTER 3 THE DYNAMIC EARTH

SECTION 1: THE GEOSPHERE

VOCABULARY GEOSPHERE CRUST MANTLE CORE LITHOSPHERE ASTHENOSPHERE TECTONIC PLATE EROSION

THE COMPOSITION OF EARTH The Earth is composed of 3 major layers Crust: less than 1% of earth’s mass, outer layer Mantle: middle layer, makes up 64% of earth’s mass Core: inner most layer, radius of 3,400 km 245 mya all land on Earth was joined in super continent Pangea

THE STRUCTURE OF EARTH 5 LAYERS Lithosphere: divided into huge tectonic plates Asthenosphere: slightly fluid layer beneath lithosphere…tectonic plates float on it Mesosphere: “middle” sphere Outer Core: made of liquid nickel and iron Inner Core: solid nickel and iron

DISCUSSION WHY IS IT IMPORTANT THAT ALL THE LAYERS OF THE EARTH MOVE EXCEPT THE CORE? WHY IS IT THAT THE CORE AND THE CRUST ARE THE ONLY SOLID LAYERS ON THE EARTH? WHY IS THIS IMPORTANT?

PLATE TECTONICS Most of the geologic activity that happens on Earth occurs here Plates are constantly moving on Earth’s surface Separate…volcanoes Collide…mountains Slip…earthquakes

Recent Quakes http://earthquake.usgs.gov/earthquakes/recenteqsww/

EROSION CAUSED BY WIND AND WATER RIVERS AND OCEANS CAN CAUSE DRAMATIC CHANGES OF THE EARTH’S SURFACE WIND CHANGES SOIL LEVELS IF THERE ARE NO PLANTS TO HOLD SOIL DOWN WITH ROOTS, THEN SOIL BLOWS AWAY

SECTION 2: THE ATMOSPHERE

VOCABULARY ATMOSPHERE TROPOSPHERE STRATOSPHERE OZONE RADIATION CONDUCTION CONVECTION GREENHOUSE EFFECT

COMPOSITION OF ATMOSPHERE 78% Nitrogen…comes from volcano eruption and plant/animal decay 21% Oxygen….comes from plant production 1% Other Gases…Argon, CO2, Methane, and Water Vapor Also contains dust….dirt, salt, ash, skin, etc. AIR PRESSURE: caused by gravity pulling atmosphere toward surface of Earth How does air pressure change as the elevation change?

LAYERS OF ATMOSPHERE TROPOSPHERE: layer nearest earth surface, almost all weather occurs in this layer STRATOSPHERE: above troposphere, contains the ozone layer (protects us from UV rays) MESOSPHERE: coldest layer of atmosphere THERMOSPHERE: layer farthest away from earth surface, extremely high temperatures, first layer of defense against solar radiation

ENERGY IN ATMOSPHERE CONDUCTION transfers heat from object to object and CONVECTION carries the heat in waves around the planet Hot air rises….cold air sinks…causes weather Solar energy heats the atmosphere…dark colors absorb heat, light colors reflect it Air is constantly moving up and down due to convection currents

GREENHOUSE EFFECT The gas in our atmosphere lets heat in, but not out….like a car and its windows Some heat will escape the atmosphere, but most is absorbed by GREENHOUSE GASSES

SECTION 3: THE HYDROSPHERE AND BIOSPHERE

VOCABULARY WATER CYCLE EVAPORATION CONDENSATION PRECIPITATION SALINITY FRESH WATER BIOSPHERE CLOSED SYSTEM OPEN SYSTEM

THE HYDROSPHERE & WATER CYCLE HYDROSPHERE – includes all water on or near earth surface WATER CYCLE – constant motion of water into air, onto land and back again Evaporation, condensation & precipitation are 3 main steps

EARTH’S OCEANS 1 of 2 ALL OCEANS ARE CONNCETED Make up 70% of Earth’s surface Largest is the Pacific…Smallest is the Arctic Ocean water is high in salt content…comes from rocks and volcanic eruptions The deeper you go in the ocean the colder it gets….WHY?

Oceans are a temperature regulator Absorbs and stores energy from the sun Absorbs over ½ of the solar radiation that reaches the surface Ocean currents are responsible for localized weather If an area has warm ocean currents then they will have warmer weather If an area has cool/cold ocean currents then they will have cool/cold weather

FRESH WATER & GROUND WATER Little more than 3% of water on earth is fresh water…mostly locked up in icecaps and glaciers Made up of river systems…interconnected rivers and tributaries Precipitation sinks into ground and collects as ground water in rock layers called AQUIFERS

THE BIOSPHERE Earth compared to apple…biosphere compared to apple skin…small layer of Earth that actually supports life Biosphere located near Earth’s surface because most of sunlight is available at Earth’s surface

ENERGY FLOW IN BIOSPHERE CLOSED SYSTEM: energy enters environment, matter does not Earth mostly closed system to matter, but open system to energy FOOD CHAINS/WEBS OPEN SYSTEM: both matter and energy are exchanged