PRESENTED BY: POOJA MAURYA ( Ph.D PRE )

In 1650 Archbishop Ussher used the Bible to calculate

that the Earth was created in 4004BC.

Later on in the mid-nineteenth century Charles

Darwin believed that the Earth must be extremely old

because he recognized that natural selection and

evolution required vast amounts of time.

About 6 billion years ago, a glowing part of the sun in form of a fiery ball of fire separated from it.

Gradually it cooled down and formed the present planet earth.

However the interior of the earth is still burning hot.

Due to tectonic forces, hills and mountains formed on the earth.

During the early period earth could not support life.

The surface was hot and the atmosphere was filled with gases of various kinds.

The present composition of the atmosphere is:

The Earth's surface was originally molten, as it cooled the volcanoes belched out massive amounts of CARBON DIOXIDE, STEAM, AMMONIA and METHANE. There was NO OXYGEN.

The STEAM condensed to form water which then produced shallow seas.

Evidence points to bacteria flourishing  3.8 billion years ago so this means that life got under way about 700 million years after the Earth was created. Such early forms of life existed in the shallow oceans close to thermal vents, these vents were a source of heat and minerals.

THE FIRST BILLION YEARS

These primitive life forms then took the next

evolutionary step and started to PHOTOSYNTHESISE

(using sunlight to convert carbon dioxide and water

to food energy and oxygen). This was an important

turning point in Earth history because the carbon

dioxide in the atmosphere was being converted to

oxygen.

These green plants went on producing oxygen (and

removing the CO2).Most of the carbon from the carbon

dioxide in the air became locked up in sedimentary

rocks as carbonates and fossil fuels. Carbon dioxide also

dissolved into the oceans.

The ammonia and methane in the atmosphere reacted

with the oxygen. Nitrogen gas was released, partly from

the reaction between ammonia and oxygen, but mainly

from living organisms such as denitrifying bacteria.

As soon as the oxygen was produced by photosynthesis it was taken out again by reacting with other elements (such as iron).This continued until about 2.1 billion years ago when the concentration of oxygen increased markedly. As oxygen levels built up and then . . . . . .

The ozone layer was formed which started to filter out harmful ultraviolet rays. This allowed the evolution of new living organisms in the shallow seas.

Temperatures on Earth are suited for life unlike

anywhere else in our Solar System. Venus is the

hottest planet in our Solar System reaching

temperatures of more than 400°C while Uranus is

the coldest planet dropping to temperatures of -

224°C. However, Earth’s average temperature is

about 14 or 15 degrees Celsius although it varies

a few degrees depending on your source.

The hottest temperature recorded on Earth

was 70.7°C (159°F) in the Lut Desert in Iran;

the temperature was recorded by a NASA

 satellite. The coldest temperature recorded

on Earth – which was measured by the Russian

Vostok Station – was -89.2°C (-129°F) on July

21, 1983 in Antarctica.

The atmosphere of Earth is a layer

of gases surrounding the planet Earth that is retained

by Earth's gravity. The atmosphere protects life on

Earth by absorbing ultraviolet solar radiation,

warming the surface through heat retention

(greenhouse effect), and

reducing temperature extremes between day and

night .

Earth’s primitive atmosphere consisted mainly of CO2 released by volcanic eruption.

About 3.5 billion years ago, photosynthesizing algae (stromatolites) began to release oxygen which steadily increased over time.

Earth cooled, oceans formed, atmosphere contained nitrogen, CO2, methane CH4, ammonia NH3, and water vapour.

Since there was hardly any O2, there was no O3

(Ozone) layer either.

UV rays, beat down on the planet.

No O2 and the planet appeared reddish in color.

1920’s Oparin and Haldane hypothesized that

under those conditions, organic molecules

could be formed.

1953 Miller and Urey performed an experiment

and produced organic molecules.

Air is the name given to atmosphere used

in breathing and photosynthesis. Dry air

contains roughly (by volume)

78.09% nitrogen, 20.95% oxygen, 0.93%

argon, 0.039% carbon dioxide, and small

amounts of other gases. Air also contains a

variable amount of water vapor, on average

around 1%.

CompositionAtmospheric chemistry

The lower pie represents the trace gases which together compose 0.039% of the atmosphere.

Troposphere The troposphere begins at the surface and extends

to between 9 km (30,000 ft) at the poles and 17 km (56,000 ft) at the equator, with some variation due to weather. The troposphere is mostly heated by transfer of energy from the surface, so on average the lowest part of the troposphere is warmest and temperature decreases with altitude

Stratosphere The stratosphere extends from the tropopause to about 51 km (32 mi; 170,000 ft). Temperature increases with height due to increased absorption of ultraviolet radiation by the ozone layer, which restricts turbulence and mixing.

The mesosphere extends from the

stratopause to 80–85 km (50–53 mi;

260,000–280,000 ft). It is the layer where

most meteors burn up upon entering the

atmosphere. Temperature decreases with

height in the mesosphere.

Biological process is a process of a living organism. Biological processes are made up of any number of chemical reactions or other events that results in a transformation.

Regulation of biological processes occurs where any process is modulated in its frequency, rate or extent. Biological processes are regulated by many means; examples include the control of gene expression, protein modification or interaction with a protein or substrate molecule.

Biological process

Physiological process, those processes specifically pertinent to the functioning of integrated living units: cells, tissues, organs, and organisms.

Reproduction Digestion Response to stimulus, a change in state or activity of a cell

or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus.

Interaction between organisms. the processes by which an organism has an observable effect on another organism of the same or different species.

Also: fermentation, fertilisation, germination, tropism, photosynthesis, transpiration.

Photosynthesis is the process of converting

light energy to chemical energy and storing it in

the bonds of sugar. This process occurs in plants

and some algae (Kingdom Protista). Plants need

only light energy, CO2, and H2O to make sugar.

The process of photosynthesis takes place in

the chloroplasts, specifically using chlorophyll,

the green pigment involved in photosynthesis.

Photosynthesis

Photosynthesis

Photosynthesis takes place primarily in plant

leaves, and little to none occurs in stems, etc.

The parts of a typical leaf include the upper

and lower epidermis, the mesophyll,

the vascular bundle(s) (veins), and

the stomates. There are two parts to

photosynthesis:

1. The light reaction happens in the thylakoid

membrane and converts light energy to

chemical energy. This chemical reaction must,

therefore, take place in the light. Chlorophyll

and several other pigments such as beta-

carotene are organized in clusters in the

thylakoid membrane and are involved in the

light reaction.

Light reaction Photosynthesis

2. The dark reaction takes place in the stroma

within the chloroplast, and converts CO2 to sugar.

This reaction doesn't directly need light in order

to occur, but it does need the products of the

light reaction . The dark reaction involves a cycle

called the Calvin cycle in which CO2 and energy

from ATP are used to form sugar

Dark Reaction Photosynthesis

THANK YOU