Levels of organization of life

Levels of Organization of Life

David Suescún Pelegay Página 1



First, we are going to see a scheme of the levels of organization of life.

⇒ Subatomic particles.

⇒ Atomic particles.

⇒ Organelles.

⇒ Cell.

⇒ Tissue.

⇒ Organ.

⇒ System.

⇒ Organism.

⇒ Family.

⇒ Population.

⇒ Biocenosis.

⇒ Ecosystem.

⇒ Biosphere.

And now, we are going to see each one with careful.



The subatomic particles are the smaller part of anything. It is composed by:

� Electrons: The electron is a subatomic particle, which has a negative mass.

� Protons: The proton is a subatomic particle, which has a positive mass.

� Neutrons: The neutron is a subatomic particle, which has a negative mass.

Now, we are going to see the characteristics of each subatomic particle.

Load Load (numbers) Weight

Electron

- �1,602 ∙ 10�� ∗ 9,1 ∙ 10��

Proton

+ �1,602 ∙ 10�� ∗ 1,6 ∙ 10��

Neutron

0 0 1,6 ∙ 10��

Coulomb*= The coulomb is the unit of electric charge. It is defined as the charge

transported by a steady current of one ampere in one second.

The subatomic particles are the base of everything.

This is an image of an atom of helium. The green balls

are the neutrons, the red balls are the protons and the

yellow balls are the electrons.



The atomic particles are formed by the union of subatomic particles.

The atomic particles are the atoms and the molecules. We are going to see each one:

� Atom: The atom is a basic unit of matter that consists of neutrons, electrons

and protons. The atom has to parts: the nucleus, which contains the neutrons

and the protons, and the cortex that contains the electrons.

An example of atom is �� !".

� Molecule: A molecule is a neutral group or two or more atoms.

An example of molecule is $�% &�'��".

This is a molecule of water.



The organelle is a specialized subunit inside a cell, everyone has an specific function.

Every organelle has an specific function:

Name Function

Nucleus Contains DNA*, controls the activity of the cell.

Chloroplast Make photosynthesis, traps energy from sunlight.

Golgi apparatus Sorting and modification of proteins.

Mitochondria Energy production from the oxidation of food substances.

Vacuole Storage water. Help to maintain homeostasis.

Centriole Anchor for cytoskeleton, helps in cell division by forming spindle

fibers.

Lysosome Breakdown of large molecules.

Nucleolus Ribosome production.

Ribosome Translation of RNA* into proteins

DNA*= Deoxyribonucleic acid.

RNA*=Ribonucleic acid.

An animal cell. Within the cytoplasm, the

major organelles and cellular structures

include: (1) nucleolus (2) nucleus (3)

ribosome (4) vesicle (5) rough

endoplasmic reticulum (6) Golgi

apparatus (7) cytoskeleton (8) smooth

endoplasmic reticulum (9) mitochondria

(10) vacuole (11) cytosol (12) lysosome

(13) centriole.



The cell is the basic structural and functional unit of all known living organism. It is the

smallest unit of life that is classified as a living thing, and is often called the building

block of life. Humans contain about 100 trillion cells; a typical cell size is 10 (� and a

typical cell mass is 1 monogram.

The cells could be classified into:

� Eukaryotic: The eukaryotic are cell which contains a nucleus. The eukaryotic cell

could be:

� Animal eukaryotic cells: The animal cells don’t have a vacuole, because the

reserves of water are bigger.

� Plant eukaryotic cells: The major difference is that this type of cells has

vacuole to store water.

� Prokaryotic: The prokaryotic are cells which don’t contain nucleus.

This are three examples of cells: (up

left) is an animal cell, (up right) is a

plant cell, both of them are eukaryotic,

the image at the left is from a bacteria,

don’t contain nucleus, and it is

prokaryotic.



A tissue is group of cells.

A tissue is a cellular organizational level intermediate between cells and a complete

organism. A tissue is an ensemble of cells, not necessarily identical, but from the same

origin, that together carry out a specific function. The tissue could be classified into

four parts:

� Connective tissue: Are fibrous tissues. They give shape to organs; blood and bone are examples of connective tissue.

� Muscle tissue: Are made up of contractile tissue of the body. This tissue moves to produce forces and cause motion, locomotion. The heart is a muscle tissue, allowing pumping the blood.

� Nervous tissue: These tissues are only used in the CENTRAL NERVOUS SYSTEM and in the PERIPHERIAL NERVOUS SYSTEM, are used to transmit information.

� Epithelial tissue: Are formed by cells that cover organ surfaces such as the skin, the airways, and the digestive tract. These tissues help to protect organism from bacteria.

This image shows the different types of tissue looked thought a telescope. The composition is different.



The organs are group of tissue.

Usually there is a main tissue (parenchyma) and sporadic tissues (stroma). For

example, the main tissue in the heart is the myocardium; a group of organs cooperate

to form systems.

This image shows the principal organs of our body.



A system is a group of organs.

These organs work together to make a specialized job.

In the human body, they are many systems, the principal are:

� Circulatory System: Is the system which pumps blood.

� Digestive System: Is the process which the food breaks down to be digested.

� Endocrine System: Is the communication within the body using hormones

made by endocrine glands…

� Excretory System: Gets rid of waste in the body; contains the digestive,

respiratory and urinary system.

� Nervous System: This system collects, transfer and process the information

with the brain, the spinal cord and the peripheral nervous system.

� Respiratory System: Are the organs used for breathing, the lungs, pharynx,

larynx, trachea, bronchi and diaphragm.

� Skeletal System: Is the structural support and protection: bones, cartilage,

ligaments and tendons.

� Urinary System: Are the organs that maintain the fluid balance and excretion of

urine.

This is an image that shows

the different systems of

the body.



An organism is a group of systems.

An organism is any living being. In at least some form, all organism could response to a

stimuli, reproduction, growth and development, and maintenance of homeostasis as a

stable whole.

This are organism.



A family is a group of organism.

Are group of living being that are like to the living being of its family.

This is a classification of the families.

This the Simpsons family tree.



Population is a group of families.



Biocenosis is a group of population.

Biocenosis describes the interacting organism living together in a habitat.



An ecosystem is a group of biocenosis.

An ecosystem is a biological environment consisting of all the organisms living in a

particular area, as well non-living beings.

The ecosystems could be very small or very big.

These are examples of

ecosystems.



The biosphere is a group of ecosystems.

The biosphere is the global sum of all ecosystems. It can also be called the zone of life

of Earth.

The Earth as a biosphere.



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Levels of organization of life