Levels of Organization of Living Things

LESSON # 2 (Chapter 1)

W H A T I S L I F E ? Life is defined in terms of a group of characteristics possessed by living things:

4- Posses an inherited .information base, encoded in DNA that allows it to function.

8- Are highly organized compared to inanimate objects.

Every one of these qualities exists in all the varieties of Earth’s living things. A simple cell can do all of the things listed above.

1- Can assimilate and use energy.

2- Can respond to their environment.

3- Can maintain a relatively constant internal environment.

5- Can reproduce, through the use of information encoded in DNA.6- Are composed of one or more cells.

7- Evolved from other living things.

The human body consists of about 100 trillion cells

(100 000 000 000 000 cells)

Each of these cell has in it a complement of DNA that is made up of 3 billion (3 000 000 000) of chemical

building blocks (atoms)

THE LIVING WORLD IS VERY COMPLEX

That is why the organization of living matter is extremely important

THE LIVING WORLD IS ORGANIZED IN A HIERARCHICAL MANNER

HIERARCHICAL MANNER: Levels of organization are progressively integrated to

make up higher levels.

Levels of Organization in Living Things

AtomsAtoms combine

to form

Molecules

SMALL MOLECULE

H O 2

MACROMOLECULE

Organelles Atoms Molecules Molecules come together to form

Highly organized structures with one special function. Ex: mitochondria, ribosomes.

Atoms combine to form

CellsCells are the smallest units of living things. Life actually occurs in cells. Each cell contains hundred of organelles.

Organelles Atoms Molecules Molecules come together to form

Highly organized structures with one special function. Ex: mitochondria, ribosomes.

Atoms combine to form

CellsCells are the smallest units of living things. Life actually occurs in cells. Each cell contains hundred of organelles.

A collection of cells that serve a common function. Ex: nervous tissue.

Tissues

Nervous tissue

Connective tissue

Epithelial tissue

Muscle tissue

Different types of tissues make up organs

Connective tissue

Epithelial tissue

Different types of tissues make up organs

Cardiac muscle tissue

Atoms Molecules Cells

OrgansTissues

Organelles Atoms combine

to form molecules.

Small molecules: water Macromolecules: DNA, proteins.

Highly organized structures with one special function. Ex: mitochondria, ribosomes.

Each cell contains hundred of organelles. They can do all things listed previously. Life actually occurs in cells.

A collection of cells that serve a common function. Ex: muscle tissue.

A functioning unit formed by several kinds of tissues. Ex: The heart, a blood vessel, the brain

Organisms can be formed by only one cell ( bacteria) or trillions of cells organized in organ systems (human).

Organ SystemsDifferent organs that work together closely. Ex: Cardio- vascular system, respiratory system, nervous system

Organisms

One-celled bacteria are also organisms

The human body consists of about 100 trillion cells (100 000 000 000 000 cells)

O R G A N I S M S

Atoms Molecules Cells

OrgansTissues Organisms

Organelles Atoms

combine to form

molecules.

Small molecules: water Macromolecules: DNA, proteins.

Highly organized structures with one special function. Ex: mitochondria, ribosomes.

Each cell contains hundred of organelles. They can do all things listed previously. Life actually occurs in cells.

A collection of cells that serve a common function. Ex: muscle tissue.

A functioning unit formed by several kinds of tissues. Ex: The heart, a blood vessel, the brain

Organisms can be formed by only one cell ( bacteria) or trillions of cells organized in organ systems (human).

Organ SystemsDifferent organs that work together closely. Ex: Cardio- vascular system, respiratory system, nervous system

Community BiospherePopulationMembers of a single type of living thing (species), living in one area.

All the kind of living things in a given area (several species).

EcosystemThe community of organisms plus all the non-living elements

The interactive collections of all the Earth’s ecosystems