ORIGIN OF LIFE
What is Biology?
The study of Life - all living things.
Their structure, function, growth, origin, evolution, and
distribution of
 living things
 interaction of life with each other
 interaction with the environment
Living things are called organisms.
Organisms include: Bacteria, Protists, Fungi, Plants and
Animals
Fundamentals
of Biology
1. Cellular organization.
All organisms consist of one or more cells—complex, organized
assemblages of molecules enclosed within membranes.
2. Sensitivity.
All organisms respond to stimuli though not always to the same stimuli
in the same ways.
3. Growth.
All living things assimilate energy and use it to grow, a process called
metabolism. Plants, algae, and some bacteria use sunlight to create
covalent carbon-carbon bonds from CO2 and H2O through
photosynthesis. This transfer of the energy in covalent bonds is
essential to all life on earth.
4. Development.
Multicellular organisms undergo systematic gene-directed changes as
they grow and mature.
Fundamentals
of Biology
5. Reproduction.
All living things reproduce, passing on traits from one generation to the
next. Although some organisms live for a very long time, no organism
lives forever. All organisms die and such ongoing life is impossible
without reproduction.
6. Regulation.
All organisms have regulatory mechanisms that coordinate internal
processes.
7. Homeostasis.
All living things maintain relatively constant internal conditions,
different from their environment
8. Heredity
All organisms on earth possess a genetic system that is based on the
replication of a long, complex molecule called DNA. This mechanism
allows for adaptation and evolution over time, also distinguishing
characteristics of living things.
LIFE?
Something Alive.
Life (of. biota) is a characteristic that distinguishes objects
that have self-sustaining biological processes from those that
do not—either because such functions have ceased (death)
or else because they lack such functions and are classified as
"inanimate.”
In biology, the science of living organisms, "life" is the
condition which distinguishes active organisms from
inorganic matter, including the capacity for growth,
functional activity and the continual change preceding
death.
Living Organisms Display Nine Characteristics
1. All Organisms are made of Cells
2. Obtain & Use Materials & Energy
3. Show movement
4. Grow & Develop
5. Maintain homeostasis and repair
6. Able to reproduce themselves
7. Respond to stimuli (Change to their Environment)
8. Living Things Evolve (Variation and Adaptation)
9. Metabolism
Characteristics of Life
1. All Organisms are made of cells, which is the functional unit of
life.

Cells are:

highly organized compartments that carry out the functions of life

separated from the outside environment by a membrane.

Some have only one cell others have millions of cells.

Some cells are very simple, and others are very complex

Cells are composed of complex mixture of materials called
protoplasm (contains proteins, lipids, carbohydrates, and
nucleic acids: DNA and RNA, water etc.)

Living things can organize material into protoplasm and
organize protoplasm to make cell and so on.

Cells can organize themselves to make a complete living being So, for this organizing capacity, they are called “Organisms”
Characteristics of Life
2. All Living things obtain energy from the environment and
use to perform their life functions.

Living things require energy

Sunlight is the ultimate energy for life on Earth
Examples: Plants gets energy by synthesizing
compounds using solar power
Animals get by ingesting nutrients
Characteristics of Life
3. All living things show movement
•
Animal: obvious/visual
•
Plant: Opening of buds, turning of leaves toward sun
•
Many animals, plants, and microscopic organisms show few or no outward signs of movement.
•
Under the microscope, cell contents of organisms are found in continuous motion.
Characteristics of Life
4. All living things grow and undergo development

Growth: Living things grow by organizing materials that
they take in to form their own special kind of protoplasm,
reproduce cells/increase the cell number, goes from one
state to another.

Development: A series of changes that take place in as an
organism grows toward final form, is called development.
By development, an organism becomes a unique living
thing with specialized parts and different from other.
Characteristics of Life
5. Living organisms maintain a stable internal environment, a property called homeostasis
•
Organisms maintain a stable internal environment, even when the external environment changes
Example: Drinking water when thirsty, Sweating to release water during summer
•
Most living things maintain and repair the materials of which they are made.
Example: Healing of cut fingers, skin cells wear away and replaced by new ones, tail recovery of house lizard.
Characteristics of Life
6. Organisms must be able to reproduce themselves
•
Only living things can produce offspring's similar to themselves.
•
Process can be different,
•

Laying eggs

Giving birth

Plant seeds develop to plants etc.
Reproduction is the process whereby all living organisms produce offspring.
Characteristics of Life
7. All living things are able to respond to certain stimuli or change in their environment (surroundings).
•
Irritability : Response to certain stimuli/stimulus -sound, touch, heat, light, moisture, food supplies etc.
Examples: A dog comes when you whistle. A fly moves when you try to swat it. A plant in a window turns its leaves
toward the light. Earthworms seek out moist soil containing decaying vegetation
o
Animal: Have nervous system, uses eyes, nose, ear to response
o
Plants: Do not have nervous system and are have slow response to light, oxygen, nutrient etc.
o
Microorganisms: Response to nutrients, environments. Even single celled organism can response
Characteristics of Life
8. Living Things Evolve (Variation and Adaptation)

Variation: Differences in some ways from one another and from their parents. Changes occur in order to
survive within changing environment.

Adaptation: The process by which a certain type of organisms becomes better suited to survive in its
environment is called adaptation.
Characteristics of Life
9. Metabolism
•
Exchange of matter and energy between an organism and its environment, and the changes that occur in
this matter and energy when they are within the organism. Sum of all the chemical reactions in an
organism
•
All require energy
•
Sunlight is the ultimate energy for life on Earth
Cellular Respiration
Cells releasing the chemical energy stored in foods
6O2 + C6H12O6
6CO2 + 6H2O
Metabolism has two distinct phases
1. Anabolism: Building up
2. Catabolism: Breaking down
The basic necessities of every living thing includes:
1. Light and Carbon Dioxide:
Needs of
Living Thing
All life forms need energy to survive. Living things use energy to grow, to
defend themselves, and to move around – this energy is provided by the
Sun – the primary source of energy.
Plants use sunlight and carbon dioxide from the air to create their own
food by photosynthesis.
Many animals then eat the plants, taking this energy into their own
bodies. Other animals then eat these plant eaters, passing the Sun's
energy from one organism to another.
The food organisms take in provides them with energy, and also provides
them with the resources, and raw materials they need to build up their
bodies, grow, and repair damage.
2. Water:
Needs of
Living Thing
Living things need water to survive. But why is water so important? All
life forms on Earth are comprised almost entirely of water. Your own body
is about 60-80% water.
Water in your blood helps transport food, and chemicals to your cells. It
helps remove waste products from your body. Water is used to cool you
down, to warm you up, and to carry out the chemical reactions that allow
you to move and grow. Another important use of water, is to keep your
body clean.
Plants use water to grow, to transport food, and to carry out chemical
reactions. In addition, plants use water as part of photosynthesis, to
create their own food.
3. Oxygen:
Without food, your body would die in a matter of weeks. Without water,
you would die in days. How long do you think you would live without
oxygen?
Most life forms use oxygen as the main ingredient in many of the
chemical reactions needed for life.
Needs of
Living Thing
Organisms get oxygen from their environment in a variety of ways. Many
land animals breath oxygen directly from the air, while ocean bearing
animals often use the oxygen dissolved in the water to survive.
4. Minerals:
The Earth’s soil contains minerals, which are essential for health and
growth. Plants take in minerals through their roots. Animals get minerals
by eating plants and/or other animals.
5. Warmth:
If it gets too hot or cold, the chemical changes which are necessary for
life will stop. In many parts of the Earth, temperatures lie between 25
deg Celsius and 30 deg Celsius. Most living things are adapted to live at
these temperatures.
6. The Biosphere:
Needs of
Living Thing
Biosphere is all those parts of the earth’s surface where living things are
found. All of the needs we have mentioned so far, energy, food, water,
and oxygen are obtained by organisms in their environment, or the space
around them.
Living things are found almost everywhere, from about 9000 meters up
mountains to at least 5000 meters under the sea.