This document defines life and discusses the key properties that characterize living organisms: order, energy processing, homeostasis, regulation, growth and development, adaptation, reproduction, and response to stimuli. It provides examples to illustrate each of these properties, such as how organisms maintain internal conditions through homeostasis, process energy from food molecules, respond to environmental cues, reproduce through specialized cells, and develop according to genetic instructions.

1. - The study of organisms and their interactions with one
another and their environments
- It may study anything from the submicroscopic and
microscopic view of a cell, to ecosystems and the whole
living planet.

2. - The science that studies life.
But what exactly is LIFE?

3. Properties of life:
-All organisms share several key characteristic features.
-These characteristics must be viewed together in order
to
define life.
• Order
• Energy processing
• Homeostasis
• Regulation
• Growth and development
• Adaptation
• Reproduction
• Sensitivity or
response to stimuli

4. • Order
- Organisms consist of highly organized and coordinated
structures made up of one or more cells.
- Even simple, singled-celled organisms are made up of one
or more cells, which composed of molecules; molecules are
turn made up of atoms.
- Most multicellular organisms are composed of organ (body
structures with a distinct function) system that work
together. Organs are made up of tissues of the same cell.
- This increasing complexity of structures shows the levels of
organization

5. • Sensitivity or
response to stimuli
- Organisms respond to diverse stimuli.
- For example, plants can bend towards the source of light, respond to
touch.
Even tiny bacteria can move toward or away from chemicals.
- Movement toward a stimulus is considered a positive response, while
movement away from a stimulus is considered as negative response.

6. • Reproduction
- Single-celled organisms reproduced b first duplicating their DNA, and
then dividing it equally as the cell prepares to form new cells.
- Multicellular organisms often produce specialized reproductive germline
cells that give rise to gametes that are used to form new individuals.
- When reproduction occurs, genes containing DNA are passed along to
an organism’s offspring.
- These genes ensure that the offspring will belong to the same species
and will have similar characteristics, such as size and shape.

7. • Growth and development
- Organisms grow and develop following specific instructions coded for by
their genes.
- These genes provide instructions that will direct cellular growth and
development, ensuring that a species’ young will grow up to exhibit many
of the same characteristics as its parents.
- Most common example is metamorphosis in animals like frogs and
butterflies. Initially the young animals look different but eventually grow
and develop to be very similar to their parents.

8. • Regulation
- Organs perform specific functions, such as carrying oxygen throughout
the body, removing wastes, delivering nutrients to every cell, and cooling
the body.
- Two examples of internal functions regulated in an organism are nutrient
transport and blood flow.
- Organisms grow and develop following specific instructions coded for by
their genes.

9. • Homeostasis
- The ability of an organisms to maintain constant internal conditions.
- For example, an organism needs to regulate body temperature through a
process known as thermoregulation. Organisms that live in cold climates,
such as the bearcat, have structures that help them withstand low
temperatures and conserve body heat.

10. • Energy processing
- Other organisms use chemical energy stored in molecules obtained from
food.
- Organisms grow and develop following specific instructions coded for by
their genes.