CHARACTERISTICS OF LIFE BIOLOGY: the study of life

Biotic Abiotic

 Life is difficult to define  Biologists focus on how life works  Life is determined by a set of characteristics that distinguish all living organisms from inanimate objects

ALL LIVING THINGS ARE MADE UP OF CELLS Cells are the smallest unit of life Cells are the smallest unit capable of sustaining life Organisms range from unicellular to multicellular Cells are the smallest unit of life Cells are the smallest unit capable of sustaining life Organisms range from unicellular to multicellular

ALL LIVING THINGS CONTAIN DNA Organisms store, use, and transmit information to live, grow, and reproduce Universal genetic code Organisms store, use, and transmit information to live, grow, and reproduce Universal genetic code

ALL LIVING THINGS REPRODUCE Produce offspring similar to themselves Pass on genetic information

ALL LIVING THINGS GROW and DEVELOP Grow in size Change in appearance and abilities Grow in size Change in appearance and abilities

ALL LIVING THINGS OBTAIN AND USE ENERGY Organisms require energy to perform their processes Obtained from their environment Organisms require energy to perform their processes Obtained from their environment Metabolism: The combination of chemical reactions where an organism builds up and breaks down materials 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 Organisms maintain a fairly stable internal environment Positive and negative feedback loops

ALL LIVING THINGS CHANGE OVER TIME 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 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 Living organisms must possess all of these characteristics simultaneously. Inanimate systems – such as viruses – may produce most of these ALL OR SOME?