Lect 1. Introduction to Environment (EIA 406)

8/8/2019 Lect 1. Introduction to Environment (EIA 406)

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Introduction to Environment

Dr. Shahid Amjad

Institute of Business Management(IoBM)





Solar SystemEarth is one of the nine planets in the solar system.

Earth is the third planet from the sun.

Each planet's characteristics are determined mostly by the

planet's density, composition, and distance from the sun.

Mercury, Venus, Earth, and Mars are known as the innerplanets. These planets are made mostly of rock.

The other five planets are known as the outer planets. Theouter planets are made mostly of gases, with the exceptionof Pluto, which is rocky like the inner planets.



C oncept Map of the Environment



Major Environmental C omponentsThe lithosphere is the layer of land that forms Earth's surface. The lithosphere includesthe rocks, soil, and sand that make up land:

The hydrosphere includes all the parts of Earth that are made up of water. Thehydrosphere includes oceans, lakes, and rivers, as well as underground water andclouds in the air.What characteristics make it possible for life to exist in so many parts of Earth? One of the most important reasons Earth can support life is the presence of liquid water.Although water exists elsewhere in the solar system, it is usually in the form of ice orvapor. On Earth, liquid water in the hydrosphere stores heat. Water is also found in thebodies of organisms. Many of the substances that all living things need dissolve inwater. Chemical reactions that take place within organisms occur in water.

The a tmosphere is the layer of air that surrounds Earth.The atmosphere is an envelope of gases that surrounds Earth and includes the air youbreathe. Scientists divide the atmosphere into four layers. Starting from the Earth's

surface, these layers are the troposphere, stratosphere, mesosphere, andthermosphere. Gases become less dense the farther they are from Earth's surface.

The BiosphereScientists spend much time trying to understand how the different parts of Earth

interact with each other and with the planet's living organisms. These interactionsamong nonliving and living parts of the Earth are the subject of ecology. The word

ecology comes from the Greek word oikos, meaning home. Ecology is the study of Earth, the home of living organisms.



Earth s LandThe LithosphereThe lithosphere varies in thickness from about 10 to 200 kilometers (km). Three maintypes of rocks make up the lithosphere: igneous rock, sedimentary rock, andmetamorphic rock. The rocks are classified on the basis of how they were formed.

Igneous Rock Below the hard, solid lithosphere, Earth's interior contains hot, meltedrocks in liquid form. W hen liquid rock cools, it solidifies to become igneous rock. Thelava that flows from a volcano cools and turns into igneous rock. Granite and basalt aretwo common types of igneous rock.

Sediment a ry Rock Rocks break down slowly over time. The tiny pieces of rock that wearoff become sediments that are carried away by wind and water. These sedimentseventually settle down into layers. A s layers of sediments accumulate, they becomecompressed and cemented into sediment a ry rock. Fossils are almost always found insedimentary rock. Limestone and sand-stone are examples of sedimentary rock.

M et a morphic Rock Pressure and heat deep in the lithosphere can cause igneous andsedimentary rocks to undergo changes in structure. Rock that has been transformed by heat and pressure is called met a morphic rock. Marble and slate are familiar examplesof metamorphic rock.



The HydrosphereThe hydrosphere flows to almost every part of the planet. The shores andriverbanks where the lithosphere and the hydrosphere meet are some of Earth'smost heavily populated parts.

70 percent of Earth's surface is covered by water. When viewed from space, Earthappears mostly blue.

More than 97 percent of the hydrosphere is salt water. Most salt water is locatedin the oceans, Seawater contains dissolved salts. About 35 grams (g) of salt aredissolved in each liter (L) of ocean water. The amounts of various types of salt inocean water is mostly Sodium chloride (Na C I) is the salt you are familiar with astable salt.

F resh water makes up less than 3 percent of the hydrosphere. More than two-thirds of this fresh water exists in frozen glaciers and ice caps. F resh water is foundin lakes, ponds, and streams, as well as underground water.

Although fresh water makes up a very small portion of the hydrosphere, it is thisfresh water that supports most life on Earth.

Because there is so little fresh water, it is a very valuable substance. The availabilityof fresh water often determines the types and numbers of organisms that an areacan support.



Fresh water resource can be divided into two types: surface water andgroundwater.

Surface water includes the water in lakes, streams, and rain runoff.

Groundwater is found beneath the surface of Earth and moves very slowlythrough small spaces in and between rocks.

Groundwater moves more easily through rock layers that are porous. A nunderground layer of porous rock that contains water is called an aq uifer.An aquifer may reach the surface of the ground, resulting in a naturalspring.

Much of the fresh water used by people is pumped to the surface fromwells drilled in aquifers. However, the water contained in aquifers is

replenished very slowly. It takes many years for rain-water to seep throughthe soil and rocks of the surface to reach an aquifer.

Because the water is pumped out faster than it is replaced, many aquifersdry up. Many communities that currently depend on the water in aquiferswill have to look elsewhere for their supply of fresh water in the future.



The AtmosphereThe atmosphere is an envelope of gases that surrounds Earth and includesthe air you breathe. The atmosphere is made up of about 78 percentnitrogen and 21 percent oxygen. Water vapor, dust particles, and smallamounts of other gases make up the remaining 1 percent of the air. Onlyabout 0.04 percent of the air is made up of carbon dioxide.

Carbon dioxide is a gas that is very important to life on Earth. C arbondioxide is one of the ingredients used by plants to make food. In thisprocess, plants add oxygen to the atmosphere. In the process of

photosynthesis, plants, algae, and certain bacteria make sugars bycombining carbon dioxide ( CO2), water, and energy from the sun.

Animals and other organisms, including plants, break down these sugars,releasing CO2, water, and energy. In humans, much of the energy is used tomaintain body functions.

Carbon dioxide is also released into the atmosphere by volcanic eruptionsand whenever fuels such as wood, coal, and gasoline are burned. Carbondioxide in the atmosphere lets sunlight in and traps the resulting heat. Thisis called the "greenhouse effect." Scientists are concerned that increasingamounts of carbon dioxide in the atmosphere are causing Earth to becomewarmer and changing climate patterns.



Scientists divide the atmosphere into fourlayers, as shown in F igure.Starting from the Earth's surface, these layersare the troposphere, stratosphere,

mesosphere, and thermosphere.Gases become less dense the farther they arefrom Earth's surface.





Troposphere

The layer of the atmosphere that touches thesurface of Earth is called the Troposphere

The troposphere extends to a height of about 8 to18 km above Earth's surface. Most of the gasmolecules in the atmosphere are in thetroposphere. The troposphere contains most of the water vapor in the atmosphere and is thelayer in which most weather occurs.

The winds that carry weather across Earth are animportant factor in the climate of an area.



Str a tosphere

Str a tosphere is beyond the troposphere, reaching a height of 50 km

above Earth.

Weather disturbances that are common in the troposphere do notoccur in the stratosphere.

The upper stratosphere contains a layer of gas called ozone. Oz one isa form of oxygen gas containing three oxygen atoms per molecule.

The oxygen you breathe in the troposphere contains only two oxygenatoms in each molecule.

The ozone layer is very important to living things because it filters outmost of the ultra-violet, or UV, radiation given off by the sun.

Ultraviolet radiation is one of many types of electromagnetic wavesproduced by the sun. without the filtering action of the ozone layer,the sun's UV radiation would destroy much of the life on Earth.



M esosphere a nd ThermosphereBeyond the stratosphere is the mesosphere , which extends up to 85km above Earth's surface. The mesosphere is the coldest layer of

the atmosphere, with temperatures as low as -100 ° C .

The thermosphere is the outermost layer of the atmosphere. Unlikethe mesosphere, the thermosphere experiences temperatures ashigh as 2000 ° C , though air pressure is less than one ten-thousandth of that at Earth's surface.

Gas molecules in one layer of the thermosphere are bombardedwith rays from the sun. These rays cause the gas molecules to loseelectrons, and they become ions.

Because of these ions, this layer of the thermosphere is called theionosphere .

When gas molecules reunite with free electrons, light is given off.This process occurs most often near Earth's poles, resulting in adisplay of lights called an aurora.



The BiosphereEarth is home to trillions of organisms. Together, the parts of thelithosphere, hydrosphere, and atmosphere where life exists make up the

biosphere.

The b iosphere is all the parts of Earth that support and contain life. Thebiosphere reaches from the floor of the ocean to the tops of the highestmountains.

All together, the biosphere is a layer blanketing the Earth about 20 kmthick. Although the biosphere is 20 km thick, most organisms live in anarrower range.

Deep below the surface of the ocean, life is rare because the pressure is sohigh and very little food is available.

Few organisms live atop the tallest mountains because the air pressure istoo low and the temperatures are too cold. Most life on Earth existsbetween 500 m below the surface of the ocean and about 6 km above sealevel.



All organisms obtain the materials they need to live from thebiosphere.

While each individual organism may live mostly on land, water, or inthe air, all organisms depend on materials from each of these threeareas of Earth.

For example, we live on the lithosphere, but breathe the air of theatmosphere, and drink the water of the hydrosphere.

A bird may live in the air, it eats food that grows on the ground,which is part of the lithosphere.

The leaves of the tree, absorb CO2 from the atmosphere andrelease oxygen and water vapor. The tree absorbs groundwater withits roots and transports the water to the leaves.



Organisms find the energy they need in many different parts of theenvironment.

Most energy originates from sunlight, which plants use. Animals, however,obtain most of their energy by eating plants and other animals.

Energy constantly flows into the biosphere as sunlight, flows throughorganisms and the environment, and eventually flows out of the biosphereas heat and is lost to space.

Because all organisms depend on the biosphere to meet their needs, theyare affected by changes in the biosphere.

For example, a change in the composition of seawater can affect theorganisms in the ocean.

The eruption of a volcano can affect organisms that live on thesurrounding land.

Anthropogenic impacts



Relationships within an Ecosystem.

Documents

Lect 1. Introduction to Environment (EIA 406)