Characteristics of life No one definitive list:  Possess an orderly structure- organization!  Require and use Energy  Reproduce new members of their species  Respond to stimuli in their environment to maintain homeostasis  Grow and develop  Species change over time through adaptation and evolve over very long periods of time

R S O A E E R G D Oliver Always and Everyday Eats Really Rank Gross Doughnuts

R espond to S timuli in environment O organized A dapt E volve E nergy needed and used R eproduce G row D evelop

Respond to stimuli  Possess “irritability” – able to respond  Stimulus must be strong enough to elicit a response  Must respond to environmental stimuli to survive and/or reproduce  Homeostasis – maintain internal conditions or environment  By internal feedback systems – communicate

Organization  One or more cells –unicellular, multicellular  Cells contain DNA molecules  Common set of compounds –organic; carbon & hydrogen  Simple to complex – at all levels  Maintain and repair atoms tissues cells compounds molecules organs organ systems organisms populations communities ecosystems biosphere

Adaptation and Evolution  Inherited structure, behavior or internal process that enables organism to respond to environmental factors and live successfully  Only an adaptation if inheritable  Must match environment  Gradual accumulation of adaptations result in evolution  Result of mutation – not intentional  Must be able to be passed along or not an adaptation  Able to move in some manner to meet needs 15 min

ENERGY REQUIRED  Ultimate source is the sun  Must be used to maintain all the other characteristics and stay alive; growth, reproduction, repair; homeostasis!  Must be obtained – ingested or absorbed; converted to a usable form  May be transformed and transferred but never created or destroyed  Respiration – exchange gases with environment  Require water for chemical reactions  METABOLISM –sum of all chemical reactions and energy exchange within an organism  Anabolic reactions – build up; simple >> complex  Catabolic reactions – break down; complex >> simple

Reproduction  Marks a successful life  Continues the species  Group of organisms that can interbreed and produce fertile offspring  Pass on genes / DNA  Sexual and/or asexual

Change over time  Grow – increase in size  Develop – change in abilities; + / -  Die – limited lifespans

All living things…  Have every characteristic at some time in their life  Similar in the variety of processes they carry out