Characteristics of Living Things EQ: What defines an organism as living vs. nonliving?

What Makes Something a Living Organism? If I where to place an unknown object on your desk what criteria would you use to determine whether or not it was a living organism?

The Ability to Reproduce All living organisms can produce offspring by either sexual or asexual reproduction –Sexual reproduction: two individuals, exchange of genetic information, new individual is a combination of both parents –Asexual reproduction: one individual produces a genetically identical offspring

Grow and Develop The organism grows and develops over a period of time Can be as simple as a change in size or as complicated as a complete change in form

Must Consume Energy All organisms must take in energy to continue life Metabolism is the technical term that describes the combination of breaking down food and building the chemicals necessary for life functions If an organism is autotrophic it take in energy from the sun If an organism is heterotrophic it eats other organisms

Respond to the Environment All living things have a desire to remain alive and do this by responding to the environment Trees bend to get the maximum amount of light possible Animals run from threats (like your shoe hovering over a roach)

Maintain an Internal Balance Homeostasis is the term used to describe a living organisms need to maintain a relatively stable set of internal conditions This includes body temperature in warm blooded organisms or water levels in all organisms If the animal cannot maintain homeostasis the animal can die

Made of Cells One of the most important distinguishing characteristics is that all living organisms are made of cells A cell is a collection of chemicals and living matter surrounded by a barrier Organisms can be either multicellular (made of many cells) or unicellular (made of a single cell)