Characteristics of Living Things What makes something an organism?

First off, basic vocabulary… Organism: Any living thing Biotic: A term used to describe any living or once living (aka dead) thing Abiotic: A term used to describe something that was never living

1. Made up of one or more cells Cell: A collection of living matter separated from its surroundings by a barrier (aka cell membrane) Unicellular: just one cell makes up the organism Multicellular: the organism is made up of more than one cell

2. Reproduction Production of new organisms or cells (growth or healing) 2 types Asexual: the offspring are identical copies of the parent Sexual: the offspring are genetic mixtures of their parents (requires 2 parent organisms)

3. Based on a universal genetic code Asexual reproduction offspring have the same traits as parents Sexual reproduction  offspring differ from their parents Genetic code is carried by DNA

4. Grow and develop Growth: increase in size (cell number) Development: change in shape and structure of an organism over time Cells go through differentiation to become specialized May include periods of rapid and dramatic change (humans, butterflies, frogs, etc)

5. Obtain and use materials and energy Metabolism: combination of chemical reactions that happen to either build materials up (ex. Muscles) or break things down (ex. Food for energy) All organisms take in materials from their environment Absorb sunlight (photosynthesis) Eat food Breathe/respire

6. Respond to their environment Stimulus: Signal to which an organism responds Internal: comes from inside (ex. When you feel hungry, you go find food…FYI, this is cause by low blood sugar, and your body triggers a hunger response) External: comes from outside (ex. How a plant grows towards the light, or how their roots respond to gravity by growing downward)

7. Maintain a stable internal environment Homeostasis When your body temperature gets too high, you sweat. The evaporation of the sweat helps to cool the temperature of your skin

8. Eliminate waste Living things must have a method for eliminating bi-products or waste products Example: Humans and other animals: Exhaling  gets rid of CO2 Urination  gets rid of excess fluids and other liquid based materials Defecation  gets rid of excess solids (i.e. parts of food that you could not digest and absorb)

Fill out the statements on the back of your note sheet with the characteristics that relate to each statement. We’ll go over the answers at the beginning of next class.  PRACTICE!!!