AP Biology
Name _______________________________
History of Life Webquest –Chapter 25
Go to www.joynerbiology.com , 3rd 9 Weeks, click on “History of Life Webquest”.
First Organic Molecules: http://www.windows2universe.org/earth/Life/miller_urey.html
The Miller-Urey Experiment
1. What was the purpose of their experiment?
2. What did they find in the liquid pool?
3. Their experiment lends support for what theory?
Miller-Urey Experiment Animation: Use the animation to answer the following:
http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter26/animation_-_millerurey_experiment.html
1. The early atmosphere contained what gases?
2. On the diagram to the right, label the water
reservoir, electrodes and condenser.
3. Put a star where they added the gases present in
the early Earth.
4. Why was the water heated?
5. What did the electric sparks mimic?
6. What did formaldehyde and hydrogen cyanide
combine to form?
7. What did their experiments show? IMPORTANT!
How did Life Originate? http://evolution.berkeley.edu/evosite/evo101/IIE2aOriginoflife.shtml
1. How old is the Earth? (you should know this!)
2. Evidence suggests that life first evolved around __________________________
3. Where do scientists believe life originated?
FYI: The first genetic material was most likely RNA, not DNA.
Click on “How did life originate?”
4. List the 5 steps that led to multicellular life.
Click on “Important Events in the History of Life". Using the timeline, put the date of each significant event.
Years
ago
Event
_________
Anatomically modern humans evolve. Seventy thousand years later, their descendents create cave
paintings — early expressions of consciousness.
__________
In Africa, an early hominid, affectionately named “Lucy” by scientists, lives. The ice ages begin, and
many large mammals go extinct.
__________
A massive asteroid hits the Yucatan Peninsula, and ammonites and non-avian dinosaurs go extinct.
Birds and mammals are among the survivors.
__________
As the continents drift toward their present positions, the earliest flowers evolve, and dinosaurs
dominate the landscape. In the sea, bony fish diversify.
__________ Dinosaurs and mammals evolve. Pangaea has begun to break apart.
_________
Over 90% of marine life and 70% of terrestrial life go extinct during the Earth’s largest mass extinction.
Ammonites are among the survivors.
__________
The supercontinent called Pangea forms. Conifer-like forests, reptiles, and synapsids (the ancestors of
mammals) are common.
__________
Four-limbed vertebrates move onto the land as seed plants and large forests appear. The Earth’s oceans
support vast reef systems.
__________ Land plants evolve, drastically changing Earth’s landscape and creating new habitats.
__________ Arthropods move onto the land. Their descendants evolve into scorpions, spiders, mites, and millipedes.
__________
Fish-like vertebrates evolve. Invertebrates, such as trilobites, crinoids, brachiopids, and cephalopods,
are common in the oceans.
__________
Multi-cellular marine organisms are common. The diverse assortment of life includes bizarre-looking
animals like Wiwaxia.
__________ Unicellular life evolves. Photosynthetic bacteria begin to release oxygen into the atmosphere.
__________ Replicating molecules (the precursors of DNA) form.
__________ The Earth forms and is bombarded by meteorites and comets.
*Using a highlighter, highlight these important events: Oxygen in atmosphere, which led to Plants evolve, which allowed
4-limbed vertebrates on land
Mass Extinctions: http://www.bbc.co.uk/nature/extinction_events
Click on each of the major extinctions to fill-in the graphic organizer.
Major
Extinction
Time
Organisms affected/
% life lost
Cause of extinction
OrdovicianSilurian
Late Devonian
Permian
*Largest Mass
Extinction in
History
Triassic Jurassic
CretaceousTertiary
Using the internet or your textbook (pg. 522), Answer this question: How have mass extinctions affected evolution?