WHAT ISALIVE?

CHARACTERISTICS OF LIFE

BIOLOGY: the study of life

Biotic

Abiotic

“Life” is difficult to define The characteristics of life must apply to all

living organisms including: _______________ , ___________________ , and ___________________.

ALL LIVING THINGS ARE MADE UP OF

CELLS

• Cells are the smallest unit capable of sustaining life

• Organisms range from unicellular to multicellular

ALL LIVING THINGS CONTAIN

DNA

• DNA is the genetic information that creates the organism

ALL LIVING THINGS CONTAIN

DNA

• DNA is the genetic information that creates the organism• Every living organism is made up of the same A, T, G, C code

98%

ALL LIVING THINGS

REPRODUCE

• Produce offspring similar or identical to themselves

• Pass on genetic information

(DNA)

ALL LIVING THINGS

OBTAIN AND USE ENERGY

• Organisms require energy to perform their processes

• Energy is obtained from their environment

• Metabolism:The combination of chemical reactions where an organism builds up and breaks down materials

ALL LIVING THINGS

RESPOND

• Organisms detect and respond to stimuli from their environment

ALL LIVING THINGS

MAINTAIN HOMEOSTASIS

• a fairly stable internal environment

• Positive and negative feedback loops

ALL LIVING THINGS

GROW and DEVELOP

• Grow in size• Change in appearance and

abilities

ALL LIVING THINGS

EVOLVE

• Populations change over long periods of time

• Each species has characteristics that vary within the population

• Some of these variations are preferred and become more pronounced over time

Living organisms must possess all of these characteristics simultaneously.

Inanimate systems – such as viruses – may produce most of these

ALL OR SOME?