Whats Life Where Does Life Come From We

What’s Life?

Where Does Life Come From? • We already learned that life doesn’t just “appear” out of thin air! • Spontaneous Generation • Remember Francesco Redi? ? ? • What was his experiment? ? ? • A controlled experiment with meat and maggots!

Redi's Hypothesis Redi made a prediction that keeping flies away from meat would prevent the appearance of maggots To test this hypothesis, he set up an experiment:

So? He set up a controlled experiment to prove that life comes from life. . . (That's important! You'll need to know that later!) But, what does it even MEAN to be ALIVE? ?

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. – Biotic Other things, like cars and rocks are – non-living. – Abiotic Living things are called *organisms*

Again… • How do we know something is ALIVE? • What’s the difference between ALIVE and DEAD and NON-LIVING?

It's ALIVE!!!! it's alive!

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 There are 9 characteristics (processes) of life: Synthesis Transport Respiration Adapt/Respond Nutrition Growth/Genetics Excretion Reproduction Cells What's Life? C

Synthesis means to make / build something more complex Think Legos !

Transport means movement Transportation is the process by which substances enter and leave our cells and become distributed within the cells Think of water getting from the roots of a tree all the way to the leaves at the top of the branches Or blood circulating through your body

Respiration (Not Breathing!) 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 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 Responding means reacting to changes in the environment Know these 2! 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

Nutrition means taking in nutrients needed to make energy and survive Ingest means to take in food Think of you munching on a Big Mac Digest 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!) Genetics is the science of heredity Heredity means how genes are passed from one generation to another

Excretion means to get rid of cellular waste You excrete in many ways: Pee-ing (Yup. . I said it!) Sweat Ever wonder why the underarm area of your favorite white tee-shirt ends up stained and yellowed? ? ? Breathing What happens when you breathe on a mirror? ? ? It’s NOT Poop!

Reproduction means making more of your own kind – Aka Offspring Two types: Asexual – one parent produces offspring which are identical to the parent Sexual – two parents 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 that particular 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: ENERGY – The primary source of energy 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? ? ?