The Development and Explanations of Life and Its Characteristics

(Various living organisms are organized from the smallest unit of cells to form tissues which form organs and organs work together to form organ systems)

What are the elements of life that evolve into organizations?

Atoms are known to join together to form the molecules that make up a cell. A cell is the smallest structural and functional unit of an organism and some organisms exist as single cells.

Human beings are multicellular because they are composed of many different types of cells. A nerve cell is one of the types of cells in the human body and it has a structure suitable for conducting nerve impulses.

Within the nucleus are positively charged particles called protons and particles without charge are neutrons that are circling around the nucleus as negatively charged particles that are known as electrons

The number and arrangement of the protons, neutrons, and electrons determine the element which is distinguished by its atomic number which equals the number of protons in the nucleus.

An element may also be assigned a mass number that refers to the sum of the protons and neutrons in the nucleus. Atoms with the same atomic number but which have different mass numbers are isotopes of the same chemical element.

A tissue is a group of similar cells that perform particular functions and nervous tissue is composed of millions of nerve cells that transmit signals to all parts of the body

An organ consists of several types of tissues and each organ belongs to an organ system. The organs of an organ system work together to perform common purposes; for example, the brain works with the spinal cord to send commands to various body parts by utilizing the nerves. Organisms; for example, vegetation, animals, and humans are each a collection of organ systems.

The various areas of biological organizations extend beyond the individuals.

All of the members of one species or groups of interbreeding organisms, in a particular area belong to a population. A tropical grassland may have a population of zebras, acacia trees, and humans.

The interacting populations of the grasslands make up a community and the community of populations interacts with the physical environment to form an ecosystem all of which make up the biosphere.

Levels of organizations that must exist to form an organ system

  • Atom = the smallest unit of an element composed of electrons, protons, and neutrons.
  • Molecule = the union of two or more atoms of the same or different elements.
  • Cell = the structural and functional unit of all living things.
  • Tissue = a group of cells with common structures and functions.
  • Organ = composed of tissues functioning together for specific purposes.
  • Organ System = composition of several organs working together.
  • Organism = an individual or a complex of individuals that contain organ systems.
  • Population = organisms of the same species in a particular habitat.
  • Community = interacting populations in a particular area.
  • Ecosystem = a community of species plus the physical environment.
  • Biosphere = regions of the earth's crust, waters, and atmosphere that are inhabited by living things.
—Compiled from information located in Human Biology by Sylvia Mader;
McGraw-Hill; New York; 2010; pages 2 & 3.

A related unit of information may be seen at Habitats for the Living.