CHARACTERISTICS OF LIVING THINGS

There are six characteristics that all living things share:

1. Made of Cells2. Require Energy3. Grow & Develop

4. Respond to Stimulus5. Reproduce

6. Composed of certain chemicals

CELLULAR ORGANIZATION• Cells are the basic building blocks of life…

of it’s alive…it’s made of cells.• Every living thing is composed of one or

more cells.• Organisms (that’s a living thing) can be

single-celled or made of many cells.• Viruses aren’t made of cells…guess what…

they’re not alive. Too bad for them…they can’t get into the movies or play the drums…as far as I know anyway.

USE ENERGY• Metabolism is the term that refers to all of

the activities that go on within a single cell or an entire organism.

• Energy is required in order to carry out all of these cellular activities.

• Metabolic processes include making food, breaking down food, moving materials in and out of cells, and building cells and their components (parts). It’s a lot of work…teenaged cells are lazy…look for them on the couch watching TV…tragic

GROW AND DEVELOP• All living things grow at some

period of their lives.• Unicellular (single-celled)

organisms simply grow larger.• Multi-cellular organisms (made of

many cells) grow by increasing their number of cells.

• Many organisms go through stages of development. Some just a few…others have many.

RESPONSE TO STIMULUS• All living things encountering a change in

their environment will respond to that change.

• Some responses are drastic and some are more subtle…you can’t even see it happen.

• If you hear a loud noise you might jump…BOO! See…calm down now. That’s a response.

• A plant might grow toward a light source…that’s a response too, but you can’t see it happening. Go ahead try to frighten a plant…it’ll ignore you and you’ll just look silly.

• A stimulus can be: gravity, light, chemicals, vibration, sound, temperature, electricity, etc.

REPRODUCE• All organisms make other organisms

like themselves.• Some living things reproduce asexually,

others sexually…some…both…no kidding!

• Asexual Reproduction – single parent produces offspring (fission, budding). Offspring is genetically identical to the parent.

• Sexual Reproduction– two parents required for reproduction (conjugation) and offspring are a combination of genetic material from both.

MADE OF Certain Biological Molecules (CHEMICALS)

1. Carbohydrates – made of sugars, used for energy

2. Proteins-made up of amino acids. Some are structural (for building) and some are enzymes (needed for chemical reactions).

3. Lipids, fats, and oils – long-term energy storage and cell membrane construction

4. Nucleic Acids (DNA & RNA)– provide the cell’s genetic instructions; also needed to make proteins.

5. Starburst (Cherry only)- needed to rot your teeth and make you all hyper from too much sugar…seriously…why are you writing this down?

If We Decide You’re Alive…Then What?

• Well…you’ll (any organism actually) need four basic things:

1.Water: Almost ever living thing consists of about 70% water. It’s needed for most chemical reactions that take place within an organism…and there are A LOT of them…reactions, that is

2. A Source of Energy: These are called nutrients (some of those chemicals we talked about). You can make your own (if you’re an autotroph…such as most plants), or…you can eat another organism…your choice. Well…not really.

3. Homeostasis: Wow! That’s a big word! So, basically it means that organisms maintain their internal conditions (like temperature, respiration, blood pressure…in vertebrates). So like, if your body is hot…you sweat and that cools you off (that’s a simple example).

4. Physical Space: All organisms need someplace to exist. Don’t confuse this with “shelter!” There are plenty of living things that live in some crazy rough places like The Dead Sea, deserts, The Poles, boiling hot springs, and deep sea hydrothermal vents. Those are some crazeeee conditions and shelter? That just ain’t happenin’

So…there you have it…

6 Criteria for Living Things and 4 Basic Needs