Characteristics of Life All living things… Title, date in notebook – required notes Paraphrase what is here – your own words! Available on my website (as are most PowerPoints/presentations)

Disclaimer! These ideas can be organized in different ways 8 characteristics – Or combine 2 characteristics to get a list of 7 Or expand a few to get a list of 10… Some characteristics are clear/straightforward; others are a bit “messy” Some organisms don’t neatly meet the characteristics!

Made up of cell(s) What is a cell? Collection of living matter surrounded by a barrier Barrier separates it from its surroundings Living organisms are either: Unicellular One cell (bacteria, some algae) Multicellular More than one cell (most species) All cells contain water

Reproduce (without completely relying on other organisms) Be able to reproduce at some point What is reproduction? Creation of new organism(s) - meet all characteristics of life Types of reproduction? Asexual – One cell/organism “splits”, forms organisms that are (mostly) genetically identical Sexual – Two cells from two parents come together – form a new organism Viruses not alive (?) Need host organisms to reproduce (this can be a gray area)

Are based on a genetic code All living things contain either DNA or RNA (or both) DNA/RNA contains the instructions necessary for life processes Instructions for proteins

Take in materials/energy, produce waste Examples? Take in: food, oxygen, sunlight,water, carbon dioxide Produce: Oxygen, carbon dioxide, methane, water, other waste * Living things do NOT all need oxygen! Most need oxygen Some organisms do NOT need it (some bacteria)

Grow and develop At some point in their lives, organisms: Grow larger, develop new features Not all living things have different types tissue (e.g., brain, hearts, lungs) Complex organisms  have different types of tissues Simple organisms  May not have different types of tissues/cells Living things DO NOT need to have a “system”

Respond to their environment All living things respond to some (few or many) stimuli in their environment Examples? Respond to smells, sights, sounds, physical stimuli, environmental conditions Totally unresponsive to all stimuli = not living

Maintain an internal balance Homeostasis? Responding to your environment to keep your internal balance in some stable range over time. Examples? 1) exercise, red face to let heat out; cold, shiver to warm up; 2) low light, pupils dilate to allow same amount of light in; 3) splashing water on face, heart rate lowers All living things maintain SOME time of internal balance

As a species, evolve over time Evidence supports – all living species have changed over time Some slowly, some quickly Every species evolves over long periods of time Evolve: DNA of a species change over time – new characteristics develop

So, were the 7 items alive? On the board…we’ll split into 4 categories (based on feedback yesterday) Alive Show all 8 characteristics Nonliving Never showed all 8 characteristics Dormant Has the potential to show all 8 characteristics Dead Once showed, but no longer show, all 8 characteristics Axolotl, plant, fires, seeds, coral, crystal, yogurt, and yellow-green blob (warmup) Note: Misconceptions on next page

Misconceptions These characteristics are NOT required for life: “Breathing” Using/breathing oxygen (not all living things need oxygen!) Moving around (not all living things move!) Drinking/taking in water All organisms use water, but not all take it in Having organs (e.g. heart) Taking in food (plants don’t take in food – they make it!) No “purpose” to life required to meet these characteristics