Is It Alive?
How do we know when something is alive?
The world is made up of many different things.
– Some things, like plants and animals, are living.
– Other things, like cars and rocks are non-living.
Living things are called *organisms*
Living or Non-living?
You know plants and animals are living things. How do you know this? All living things (YES, ALL LIVING THINGS)
have certain characteristics in common. We will remember them by remembering THIS
phrase: STRANGER-C
S T R A N G E R C There are 9 characteristics (processes) which are necessary
for life:
Synthesis Transport Respiration Adaptation/Response Nutrition Growth/Genetics Excretion Reproduction Cells
Synthesis
Synthesis means to make / build something more complex Think Legos
Transport
Transport means movement Transportation is the process
by which substances enter and leave our cells and become distributed within the cells Think of water moving from the
roots of a tree all the way to the leaves at the top of the branches
Think of your blood circulating through your body
Respiration
Cell Respiration the process of changing energy stored in food into a chemical energy (ATP) which cells can use
Two types: Aerobic – Uses oxygen Anaerobic – Does not use oxygen
AKA: FERMENTATION
Adapt/Respond Adaptation is any inherited factor that improves the
chances of survival All living things need to adapt and respond to their
environment if they are to survive Adapting means changing to be better able to survive
Think of polar bears in sub-zero temperature Responding means reacting to changes in the
environment Stimulus = any factor (signal) that causes a change/response
- It’s a change in the environment which causes a reaction Doorbell Phone Ringing
Response = a reaction to a change caused by a stimulus Goosebumps Sweat
Kn
ow
th
ese
2!
Nutrition Nutrition means taking in
nutrients needed to make energy and survive Ingestion means to take IN food
Think of you munching on a Big Mac Digestion means breaking down
large “stuff” (complex materials) into smaller/simpler forms That Big Mac doesn't go sloshing
around beneath your skin, smearing ooey-gooey yummy-ness all over your muscles and bones, does it????
Growth & Genetics
Growth means to increase in size and/or number Even though we appear to stop growing… we
always need new cells to repair/replace old ones! Genes are necessary for this to happen!
Your GENES are made up of DNA that contains the instructions for the cell (and we'll learn TONS about that later on!)
Excretion Excretion means to get rid of
cellular waste (NOT POOP!) You excrete in many ways:
Pee-ing (Yup.... I said that too!) Sweat
Ever wonder why the underarm area of your favorite white tee-shirt ends up stained and yellowed????
Breathing What happens when you
breath on a mirror???
Reproduction Reproduction means that living
things are able to make more of their own kind (offspring).
Two types: Asexual – one individual produces
offspring which are identical to the parent
Sexual – two individuals are required to produce offspring and the organism they produce is not identical to either parent
This is the ONLY life-characteristic that is
NOT required for an organism to stay alive....
CELLS
Cells are the building blocks of EVERY living organism The basic unit of structure and
function of all living things EVERY single cell is actually
alive and.... Can exist on it’s own
unicellular Or work with other cells to make
a different organism multicellular
Needs of Living Things
• ALL living things NEED certain things to survive
• Can you think of anything you would NEED in order to stay alive?
• Remember… NEEDING something is different from WANTING something!
• List a few “NEEDED” things:
Needs of Living ThingsALL living things NEED certain things to
survive:
ENERGY – The primary source of energy for ALL life on earth is the SUN
FOOD & WATER – ~70% of your body is water!
AIR – Air is made of the gases which plants and animals need to survive
LIVING SPACE – Living things need a place to get food, water and energy
PROPER TEMPERATURE –The internal temperature must remain in a certain range….
Important Words to Know !!!!!
Metabolism = ALL the chemical reactions occurring within an organism
Homeostasis = “Steady State”. Maintaining a stable internal environment (Even when the external environment changes!)- What’s your body temperature??? Do you think it changes (inside) if it’s super cold
outside??? Super hot???