Why do wetland birds have different bills?

Answer 1

what are the four major domains of the earth?Asked by ashu.shane...(student), on 15/2/11

Answers

The four major domains of the earth are

1)atmosphere

2)Biosphere

3) Hdrosphere

4) LithospherePosted by verma.kirti111(student), on 15/2/11

The four major domains of the earth are

1)Atmosphere(Gases)

2)Biosphere(Living Beings)

3) Hydrosphere(Water)

4) Lithosphere(Land)

If u fl my ansr s crrct tn gv me a thumpzz up

Posted by sAnSkRuTiK(student), on 15/2/11

Lithosphere(Land) Hydrosphere(Water) Atmosphere(Gases) Biosphere(CONNECTION OF LAND WATER AND AIRPosted by swayamshubham1...(student), on 10/3/12

Lithosphere ( Land)

Hydrosphere ( Water )

Atmosphere ( Air )

Biosphere ( The parts of the Earth where life is found , including land , water and the lower part of the atmosphere )Posted by ayshasamreen9...(student), on 10/3/12

The four major domains of the earth are

1)atmosphere

2)Biosphere

3) Hdrosphere

4) LithospherePosted by jrathi03...(student), on 28/10/12

hydrosphere

lithosphere

atmosphere

biosphere BiosphereThe biosphere is the space on or near Earth's surface that contains and supports living organisms. It is subdivided into the lithosphere, atmosphere, and hydrosphere. The lithosphere is Earth's surrounding layer, composed of solids such as soil and rock; it is about 80 to 100 kilometers (50 to 60 miles) thick. The atmosphere is the surrounding thin layer of gas. The hydrosphere refers to liquid environments such as lakes and oceans that lie between the lithosphere and atmosphere. The biosphere's creation and continuous existence results from chemical, biological, and physical processes.

Requirements for lifeFor organisms to live, certain environmental conditions (such as proper temperature and moisture) must exist, and the organisms must be supplied with energy and nutrients (food). All the animal and mineral nutrients necessary for life are contained within Earth's biosphere. Nutrients contained in dead organisms or waste products of living cells are transformed back into compounds that other organisms can reuse as food. This recycling of nutrients is necessary because there is no source of food outside the biosphere. Words to KnowDecomposition: The breakdown of complex molecules---molecules of which dead organisms are composed---into simple nutrients that can be reutilized by living organisms.

Energy: Power that can be used to perform work, such as solar energy.

Global warming: Warming of the atmosphere that results from an increase in the concentration of gases that store heat, such as carbon dioxide.

Nutrient: Molecules that organisms obtain from their environment; they are used for growth, energy, and various other cellular processes.

Nutrient cycle: The cycling of biologically important elements from one molecular form to another and back to the original form.

Photosynthesis: Process in which plants capture light energy from the Sun and use it to convert carbon dioxide and water into oxygen and organic molecules.

Respiration: Chemical reaction between organic molecules and oxygen that produces carbon dioxide, water, and energy.

Energy is needed for the functions that organisms perform, such as growth, movement, waste removal, and reproduction. It is the only requirement for life that is supplied from a source outside the biosphere. This energy is received from the Sun. Plants capture sunlight and use it to convert carbon dioxide and water into organic molecules, or food, in a process called photosynthesis. Plants and some microorganisms are the only organisms that can produce their own food. Other organisms, including humans, rely on plants for their energy needs.

The major elements or chemical building blocks that make up all living organisms are carbon, oxygen, nitrogen, phosphorus, and sulfur. Organisms are able to acquire these elements only if they occur in usable

chemical forms as nutrients. In a process called the nutrient cycle, the elements are transformed from one chemical form to another and then back to the original form. For example, carbon dioxide is removed from the air by plants and incorporated into organic compounds (such as carbohydrates) by photosynthesis. Carbon dioxide is returned to the atmosphere when plants and animals break down organic molecules (a process known as respiration) and when microorganisms break down wastes and tissue from dead organisms (a process known as decomposition).

Evolution of the biosphereDuring Earth's long history, life-forms have drastically altered the chemical composition of the biosphere. At the same time, the biosphere's chemical composition has influenced which life-forms inhabit Earth. In the past, the rate at which nutrients were transformed from one chemical form to another did not always equal their transformation back to their original form. This has resulted in a change in the relative concentrations of chemicals such as carbon dioxide and oxygen in the biosphere. The decrease in carbon dioxide and increase in atmospheric oxygen that occurred over time was due to photosynthesis occurring at a faster rate than respiration. The carbon that was present in the atmosphere as carbon dioxide now lies in fossil fuel deposits and limestone rock.

Scientists believe that the increase in atmospheric oxygen concentration influenced the evolution of life. It was not until oxygen reached high concentrations such as exist on Earth today that multicellular organisms like ourselves could have evolved. We require high oxygen concentrations to accommodate our high respiration rates and would not be able to survive had the biosphere not been altered by the organisms that came before us.

Current developmentsMost research on the biosphere is to determine the effect that human activities have on the environment---especially on nutrient cycles. Application of fertilizers increases the amount of nitrogen, phosphorus, and other nutrients that organisms can use for growth. These excess nutrients damage lakes, causing overgrowth of algae and killing fish. Fuel consumption and land clearing increase carbon dioxide levels in the atmosphere and may cause global warming (a gradual increase in Earth's temperature) as a result of carbon dioxide's excellent ability to trap heat.

Biosphere 2. Interest in long-term, manned space exploration has also generated research into the development of artificial biospheres. Extended missions into space require that nutrients be cycled in a volume no larger than a building. The Biosphere 2 Project, which received a great deal of popular attention in the early 1990s, provided insight into the difficulty of managing such small, artificial biospheres. The idea behind the project was to establish a planet in miniature where the inhabitants not only survived but learned to live cooperatively and happily together. This is quite revealing, given that human civilization has found it difficult to manage sustainably the much larger biosphere of planet Earth.

Gaia HypothesisThe Gaia hypothesis (pronounced GAY-a), named for the Greek Earth goddess Gaea, is a recent and controversial theory that views Earth as an integrated, living organism rather than as a mere physical object in space. The Gaia hypothesis suggests that all organisms and their environments (making up the biosphere) work together to maintain physical and chemical conditions on Earth that promote and sustain life. According to the hypothesis, organisms interact with the environment as a homeostatic (balancing) mechanism for regulating such conditions as the concentrations of atmospheric oxygen and carbon dioxide. This system helps to maintain conditions within a range that is satisfactory for life. Although scientists agree that organisms and the environment have an influence on each other, there is little support within the scientific community for the notion that Earth is an integrated system capable of regulating conditions to sustain itself. The Gaia hypothesis is a useful concept, however, because it emphasizes the relationship between organisms and the environment and the effect that human activities have on them.

One of the most spectacular structures ever built, Biosphere 2 is located in the Sonoran Desert at the foot of the Santa Catalina Mountains not far from Tucson, Arizona. It is the world's largest greenhouse, made of tubular steel and glass, covering an area of three football fields---137,416 square feet (12,766 square meters)---and rising to a height of 85 feet (26 meters) above the desert floor. Within the structure, there is a human habitat and a farm for the Biospherians or inhabitants to work to provide their own food. There are five other wild habitats or biomes representing a savannah, a rain forest, a marsh, a desert, and an ocean. Biosphere 2 is completely sealed so no air or moisture can flow in or out. Nearby are two balloon-like structures that operate like a pair of lungs for Biosphere 2 by maintaining air pressure inside. Only sunlight and electricity are provided from outside.

On September 26, 1991, four women and four men from three different countries entered the Biosphere 2 and the doors were sealed for the two-year-long initial program of survival and experimentation. During this time, the Biospherians attempted to run the farm and grow their own food in the company of some pigs, goats, and many chickens. They shared the other biomes with over 3,800 species of animals and plants that were native to those habitats. The resident scientists observed the interactions of plants and animals, their reactions to change, and their unique methods of living. The Biospherians also had the assignment of experimenting with new methods of cleaning air and water.

On September 26, 1993, the Biospherians emerged from Biosphere 2. It had been the longest period on record that humans had lived in an "isolated confined environment." Unfortunately, the experiment did not live up to expectations. The Biospherians experienced many difficulties, including an unusually cloudy year in the Arizona desert that stunted food crops, rapid growth and expansion of some ant species, and unusual behavior of bees fooled by the glass walls of the structure. In 1996, Columbia University took over operation of the facility, opening a visitors' center later that year. Biosphere 2 has been maintained for study but without human inhabitants. Its future remains uncertain.learn your textbooks

Try it today.

12MAJOR DOMAINS OF THE EARTH

As you have read in the first chapter, the earth is the

only planet which has life. Human beings can live here

because the life sustaining elements of land, water and

air are present on the earth.

The surface of the earth is a complex zone in which

three main components of the environment meet,

overlap and interact. The solid portion of the earth on

which we live is called the Lithosphere. The gaseous

layers that surround the earth, is the Atmosphere,

where oxygen, nitrogen, carbondioxide and other gases

are found. Water covers a very big area of the earth's

surface and this area is called the Hydrosphere. The

Hydrosphere comprises water in all its forms, that is,

ice, water and water vapour.

The Biosphere is the narrow zone where we find

land, water and air together, which contains all forms

of life.

LITHOSPHERE

The solid portion of the earth is called the Lithosphere.

It comprises the rocks of the earth's crust and the thin

layers of soil that contain nutrient elements which

sustain organisms.

There are two main divisions of the earth's surface.

The large landmasses are known as the continents

and the huge water bodies are called the ocean basins.

All the oceans of the world are connected with one

another. Look at the map of the world (Figure 5.1). Are

all the land masses connected with one another?

The level of seawater remains the same everywhere.

Elevation of land is measured from the level of the sea,

which is taken as zero.

5

Word Origin

In Greek language,

Lithos means Stone;

Atmos means Vapour;

Hudor means Water;

and Bios means Life.

Can you make words using

the above?

MAJOR DOMAINS OF THE EARTH 31

Figure 5.1 : The World : Continents and Oceans

32 THE EARTH : OUR HABITAT

The highest mountain peak Mt. Everest is 8,848

metres above the sea level. The greatest depth of 11,022

metres is recorded at Mariana Trench in the Pacific

Ocean. Could you imagine that depth of sea is much

more than the highest point?

Continents

There are seven major continents. These are separated

by large water bodies. These continents are -- Asia,

Europe, Africa, North America, South America,

Australia and Antarctica. Look at the map of the world

(Figure 5.1) and notice that the greater part of the land

mass lies in the Northern Hemisphere.

Asia is the largest continent. It covers about onethird

of the total land area of the earth. The continent

lies in the Eastern Hemisphere. The Tropic of Cancer

passes through this continent. Asia is separated from

Europe by the Ural mountains on the west (Figure

5.1). The combined landmass of Europe and Asia is

called the Eurasia (Europe + Asia).

Europe is much smaller than Asia. The continent

lies to the west of Asia. The Arctic Circle passes through

it. It is bound by water bodies on three sides. Look at

the map of the world and locate it.

Africa is the second largest continent after Asia.

The Equator or 00 latitude runs almost through the

middle of the continent. A large part of Africa lies in

the Northern Hemisphere. Look at the Figure 5.1; you

will find that it is the only continent through which

the Tropic of Cancer, the Equator and the Tropic of

Capricorn pass.

The Sahara Desert, the world's largest hot desert,

is located in Africa. The continent is bound on all sides

by oceans and seas. Look at the world map (Figure 5.1).

You will notice that the world's longest river the Nile,

flows through Africa. Notice where the Equator, the

Tropic of Cancer and the Tropic of Capricorn pass in

the map of Africa.

North America is the third largest continent of the

world. It is linked to South America by a very narrow

strip of land called the Isthmus of Panama. The

continent lies completely in the Northern and Western

Hemisphere. Three oceans surround this continent.

Can you name these oceans?

Do you know?

Edmund Hillary

(Britain) and

Tenzing Norgay Sherpa

(India) were the first men

to climb the highest

mountain peak Mt. Everest

on the planet earth on 29th

May, 1953.

Junko Tabei (Japan)

was the first woman to

reach the summit on 16th

May, 1975. The first

Indian woman to climb the

highest peak on 23rd May,

1984 was Bachendri Pal.

MAJOR DOMAINS OF THE EARTH 33

South America lies

mostly in the Southern

Hemisphere. Which two

oceans surround it on

the east and the west?

The Andes, world's

longest mountain

range, runs through its

length from north to

south (Figure 5.1).

South America has the

world's largest river, the

Amazon.

Australia is the

smallest continent that

lies entirely in the

Southern Hemisphere.

It is surrounded on all

sides by the oceans and

seas. It is called an

island continent.

Antarctica, completely in the Southern Hemisphere,

is a huge continent. It is larger than the combined

area of Europe and Australia. The South Pole lies

almost at the centre of this continent. As it is located

in the South Polar Region, it is permanently covered

with thick ice sheets. There are no permanent human

settlements. Many countries have research stations in

Antarctica. India also has research stations there. These

are named as Maitri and Dakshin Gangotri.

HYDROSPHERE

The earth is called the blue planet. More than 71 per

cent of the earth is covered with water and 29 per cent

is with land. Hydrosphere consists of water in all its

forms. As running water in oceans and rivers and in

lakes, ice in glaciers, underground water and the water

vapour in atmosphere, all comprise the hydrosphere.

More than 97% of the Earth's water is found in the

oceans and is too salty for human use. A large

proportion of the rest of the water is in the form of

icesheets and glaciers or under the ground and a very

small percentage is available as fresh water for human

Figure 5.2 : Isthmus and Strait

Name the Strait

between India

and Sri Lanka.

34 THE EARTH : OUR HABITAT

Oceans

Oceans are the major part of hydrosphere. They are

all interconnected.

The ocean waters are always moving. The three chief

movements of ocean waters are the waves, the tides

and the ocean currents. The four major oceans are the

Pacific Ocean, the Atlantic Ocean, the Indian Ocean and

the Arctic Ocean, in order of their size (Figure 5.1).

The Pacific Ocean is the largest ocean. It is spread

over one-third of the earth. Mariana Trench, the

deepest part of the earth, lies under the Pacific Ocean.

The Pacific Ocean is circular in shape. Asia, Australia,

Figure 5.3 : Comparative size of the continents

Count the squares given in Figure 5.3 and answer the following :

(a) Name the largest and smallest continents; (b) Which is larger -- North or South America?

use. Hence, despite being a 'blue planet' we face

a shortage of water!!

MAJOR DOMAINS OF THE EARTH 35

North and South Americas surround it. Look at the

map and find out the location of the continents around

the Pacific Ocean.

The Atlantic Ocean is the second largest Ocean in

the world. It is 'S' shaped. It is flanked by the North

and South Americas on the western side, and Europe

and Africa on the eastern side. The coastline of Atlantic

Ocean is highly indented. This irregular and indented

coastline provides ideal location for natural harbours

and ports. From the point of view of commerce, it is

the busiest Ocean.

The Indian Ocean is the only ocean named after a

country, that is, India. The shape of ocean is almost

triangular. In the north, it is bound by Asia, in the

west by Africa and in the east by Australia.

The Arctic Ocean is located within the Arctic Circle

and surrounds the North Pole. It is connected with the

Pacific Ocean by a narrow stretch of shallow water

known as Berring strait. It is bound by northern coasts

of North America and Eurasia.

ATMOSPHERE

The earth is surrounded by a layer of gas called the

atmosphere. This thin blanket of air is an integral

and important aspect of the planet. It provides us with

the air we breathe and protects us from the harmful

effects of sun's rays.

The atmosphere extends up to a height of about

1,600 kilometres. The atmosphere is divided into five

layers based on composition, temperature and other

properties. These layers starting from earth's surface

are called the troposphere, the stratosphere, the

mesosphere, the thermosphere and the exosphere.

The atmosphere is composed mainly of nitrogen and

oxygen, which make up about 99 per cent of clean,

dry air. Nitrogen 78 per cent, oxygen 21 per cent and

other gases like carbondioxide, argon and others

comprise 1 per cent by volume. Oxygen is the breath

of life while nitrogen helps in the growth of living

organisms. Carbon dioxide, though present in minute

amount, is important as it absorbs heat radiated by

the earth, thereby keeping the planet warm. It is also

essential for the growth of plants.

The density of the atmosphere varies with height. It Figure 5.4 : Layers of the Atmosphere

Exosphere

36 THE EARTH : OUR HABITAT

is maximum at the sea level and

decreases rapidly as we go up. You

know, the climbers experience

problems in breathing due to this

decrease in the density of air. They

have to carry with them oxygen

cylinders to be able to breathe at

high altitudes. The temperature also

decreases as we go upwards. The

atmosphere exerts pressure on the

earth. This varies from place to place.

Some areas experience high pressure

and some areas low pressure. Air

moves from high pressure to low pressure. Moving air

is known as wind.

BIOSPHERE -- THE DOMAIN OF LIFE

The biosphere is the narrow zone of contact between

the land, water and air. It is in this zone that life, that

is unique to this planet, exists. There are several

Figure 5.6 : The Biosphere

Figure 5.5 : A mountaineer

MAJOR DOMAINS OF THE EARTH 37

1. Answer the following questions briefly.

(a) What are the four major domains of the earth?

(b) Name the major continents of the earth.

(c) Name the two continents that lie entirely in the Southern Hemisphere.

(d) Name the different layers of atmosphere.

(e) Why is the earth called the 'blue planet'?

(f) Why is the Northern Hemisphere called the Land Hemisphere?

(g) Why is the Biosphere important for living organisms?

species of organisms that vary in size from microbes

and bacteria to huge mammals. All the living

organisms including humans are linked to each other

and to the biosphere for survival.

The organisms in the biosphere may broadly be

divided into the plant kingdom and the animal

kingdom. The three domains of the earth interact with

each other and affect each other in some way or the

other. For example, cutting of forests for fulfilling our

needs of wood, or clearing land for agriculture may

lead to fast removal of soil from slopes. Similarly earth's

surface may be changed due to natural calamities like

earthquakes. For example, there could be submergence

of land, as happened in the case of Tsunami recently.

Parts of Andaman & Nicobar islands were submerged

under water. Discharge of waste material into lakes

and rivers makes the water unsuitable for human use.

It also damages other forms of life.

Emission from industries, thermal power plants

and vehicles, pollute the air. Carbon dioxide (CO2) is

an important constituent of air. But increase in the

amount of CO2 leads to increase in global temperatures.

This is termed as global warming. There is thus, a

need to limit the use of resources of the earth to

maintain the balance of nature between the domains

of the lithosphere, the atmosphere and the

hydrosphere.

38 THE EARTH : OUR HABITAT

2. Tick the correct answers.

(a) The mountain range that separates Europe from Asia is

(i) the Andes (ii) the Himalayas (iii) the Urals

(b) The continent of North America is linked to South America by

(i) Isthmus (ii) Strait (iii) Canal

(c) The major constituent of atmosphere by per cent is

(i) Nitrogen (ii) Oxygen (iii) Carbon dioxide

(d) The domain of the earth consisting of solid rocks is

(i) the Atmosphere (ii) the Hydrosphere (iii) the Lithosphere

(e) Which is the largest continent?

(i) Africa (ii) Asia (iii) Australia

3. Fill in the blanks.

(a) The deepest point on the earth is _____________ in the Pacific Ocean.

(b) The _____________ Ocean is named after a country.

(c) The _____________ is a narrow contact zone of land, water and air that

supports life.

(d) The continents of Europe and Asia together are known as _____________.

(e) The highest mountain peak on the earth is _____________.

1. Cut the outline of the continents from an outline map of the world and

arrange them according to their decreasing sizes.

2. Cut the outline of the continents from an outline map of the world and try

to fit them together as a Jig-saw puzzle.

3. Collect pictures of expeditions to the Himalayas. Write about the kind of

equipment carried by the climbers for protection against sunshine,

temperature and the lack of air.

Map Skills

1. On the outline map of the world, mark the following :

Europe, Asia, Antarctica, South America, Australia, Indian Ocean, Pacific

Ocean, Atlantic Ocean, Ural Mountains and Isthmus of Panama.