CHARACTERISTICS OF LIVING THINGS

CELLULAR ORGANIZATION

• A cell is the basic building block of life.
• The cell is the basic unit of structure and function of all living things.
• Organisms may be made up of one cell or many cells.

SINGLE CELL ORGANISMS

• Some organisms, like bacteria, are made up of only a single cell.
• These organisms are unicellular organisms.
• This single cell carries out all functions necessary for life.

MULTICELLULAR ORGANISMS

• Organisms that are made up of many cells are called multicellular.
• Humans are made up of trillions of cells.
• Cells may be specialized to carry out certain functions.
• Specialized cells work together to keep an organism alive.

GROWTH AND DEVELOPMENT

• All living things grow and develop.
• Development is a process of change where an organism becomes more complex.
• During development, cells may change from one type to another.
• A cell may become specialized for a particular purpose.

GROWTH

• Growth involves cells growing and multiplying.
• Cells are only able to grow to a certain size.
• For and organism to grow, the number of cells has to increase.

ENERGY USE

• Organisms get energy from taking in and breaking down food sources.
• The chemicals reactions through which an organism breaks down materials to get energy, and then uses energy to build materials back up again is called metabolism.

ENERGY USE

• An organism uses energy for all of its life processes
• It uses energy for growth and development
• It uses energy for repairs of injured or broken parts
• It uses energy for every day functions, like movement

RESPONSE TO SURROUNDINGS

• All living things respond to changes in their environment.
• A change in the environment that causes the organism to react is called a stimulus.
• A stimulus might be a change in light, sound, temperature, or other factors.

RESPONSE

• An organism reacts to a stimulus with a response.
• A response is an action or a change in behavior.
• For example, have you ever jumped when you heard a loud noise? Maybe a really loud clap of thunder?
• That's a response!

REPRODUCTION

• A characteristic of living things is the ability to reproduce.
• Organisms may reproduce in different ways.
• Asexual reproduction involves only one parent, and produces offspring that are identical to the parents.

SEXUAL REPRODUCTION

• Sexual reproduction involves two parents and combines their genetic material.
• This type of reproduction produces an offspring that is genetically different from both parents.
• Mammals, birds, and most plants sexually reproduce.

CHEMICALS OF LIFE

• The cells of living things are made up of chemical molecules
• The most abundant molecule is water.
• Two other chemical molecules, proteins and lipids, are building materials of cells.
• The chemicals called carbohydrates are a cell's main source of energy.
• Nucleic acids are the genetic material of the cell, and are found in the nucleus.