From a newly formed earth, to Eukaryotes!

Chapter 18read the chapter… seriously!

Life comes from life• When meat spoils, or bread gets moldy,

where do the parasites come from?• Do they live in the food? Do they fall

from the sky? Are they created from thin air? (yes, yes and no)

• We know the answer to these questions thanks to _____________… and his famous experiment

• Boiled broth, allowed air to touch one sample but not another, the one with no air did not spoil__________________ ______________________________ ____________________________!

• What about the FIRST LIFE?

The earth’s origin• The earth started as a cold lump of

matter… later heated up with meteor, and gravitational forces– Spinning motion forced more dense

materials to the center (Nickel and Iron)

• The earth then became a very hostile _________________.– Large amounts of H2, CO, CO2,

N2, H2O vapor, CH4 (________), NH3 (_________)

– Really ____ with lots of volcanic activity, UV radiation and lightning

– In short we would all be goners!

So how did Life Start?• Stanly Miller – _______________________

_______________________ _______________________

• Some scientists doubt his original component ingredient list was correct and so offer a different hypothesis– ________________________

________________________ ________________________

• Either way eventually the organic molecules arranged themselves into cells

Early Cells• Before you can have ‘cells’ you need

three basic things…1. _________… a way to get food/energy2. Plasma membrane… _____________

___________________________3. __________… a way to ___________

• These first life forms would have needed to make their own food (____________), be independent from oxygen (________) and able to tolerate very HOT conditions!

Steps 1 and 2

1. Molecules, _________, started interacting with each other… they formed ______________ ____________and made more and more copies of the product

2. Groups of _______________ molecules formed _________ between different pathways– forming a ____________.

• These protocells still ________________, they just formed, unformed, and reformed…

Step 3… RNA world• RNA is _______- it can _____

_________, ___________, and ____________

• It still does all of that in some species with small genomes (______________________ _______________.)

• The RNA world is the theory that in early cells, RNA was the holder of all genetic information, the catalyst for reactions and the messenger it is today

Golden age of Prokaryotes• So… In a Reduction atmosphere life

evolved from non-living matter. • Fossils of similar bacteria can be

found in fossilized mats of bacteria called ____________– Started forming ________– Include many kinds of bacteria…– One very important one is…

_______… they have a ________ _____________ that releases _________ into the atmosphere!

– _________ accumulated in the ocean, then the air.

Life Changed the Atmosphere

As the prokaryotes released O2 into the atmosphere it cause 3 things to happen

1. Life could no longer ____________________. 2. ______________was able to evolve and take

over (because we know its WAY more efficient) 3. The ___________ formed and reduced the

amount of __________ streaming onto the earthThese changes paved the way for less hardy, but

more complex organisms… any guesses?

The rise of the Eukaryotes…• ___ billion years ago prokaryote and eukaryote lineages split• ___ bya eukaryotes emerged, with a system of organelles and

division of labor. • ________ were the first modern Eukaryotes (_________)• But how did they get those organelles… well we have a theory for

that…

In the beginning (or a couple million years later)

• Eukaryotes evolved from prokaryotes using a couple cool features

1. _____________…When the membrane folds in on itself, giving _________________________(like ER)

2. ________________… One cell living within another, benefiting both (like ___________________________)

Endosymbiosis Case Study: Mitochondria

• The Mitochondria was engulfed by a prokaryotic cell that had already undergone membrane infolding.

• A symbiotic relationship formed – the mitochondria to concentrate only

on making ATP. – the cell that in turn took care of

everything else.• Eventually the two became so

dependent they were inseparable… each unable to live without the other

• ** HAVE TO REPLICATE TOGETHER!– Mitochondrial DNA looks like that of

prokaryotes!