Origin: How Life Began Worksheet
Life has existed on the surface of the Earth for only what percent of the Earth's history?
10%
Deep within the mines shown in Africa, what is the temperature and air pressure?
120 degrees F and twice the air pressure on the surface of the earth
Once all of the iron had been use up in the primitive oceans, the oxygen levels rose to our current atmospheric level of what percent?
21%
On the 24 hour clock presented in the video, humans arrive on the scene at what time?
23:59
How many billions of years ago are scientists fairly certain that life was present on our planet?
3.8 billion years
Earth was create approximately how many billion years ago?
4.5 years ago
The meteorite crater shown from Arizona was formed from an impact how many years ago?
50,000 years ago
Name the scientist who in the 1950's testing how organic (carbon-based) molecules may have formed on the early Earth.
Stanley Miller
What was found inside a meteorite that struck Australia?
amino acids
When this scientist ran an electric current through his apparatus, he found that what had formed?
amino acids
What are "cyanobacteria"?
blue-green bacteria that live on top of stromatolites
How did scientist Jennifer Blank test the hypothesis that organic molecules (amino acids and others) might have been brought to Earth by a meteorite and survived the impact?
by using a gas powered gun that would stimulate the extreme temperatures and pressures that are released when a comet smashes into earth
Name the four main elements from which life is constructed?
carbon, hydrogen, oxygen, nitrogen (CHON)
What was scientist Stephen Mojzsis looking for in the rocks in Greenland?
chemical fingerprints of ancient bacteria or microbes
What extraterrestrial structure might be described as a "giant dirty snowball" made of ice and rock?
comets
What was happening during the 600 million years known as the "time of heavy bombardment"?
comets and asteroids pounded earth
The caves investigate by Penny Boston at Cueva de Villa Luz are filled with what noxious gas?
hydrogen sulfide
What do the snottites use as a source of energy?
hydrogen sulfide
3.6 billion years ago, most of the oxygen produced by photosynthesis was immediately converted into what compound (metal oxide) that today is mined to make steel?
iron
What two gases do bacteria found deep in the mines of Africa seem to live on?
methane, ethane, propane
In Western Australia, what types of organisms formed the living and fossilized "stromatolites" that are found there?
microbes
What have scientists found deep within these mines?
microorganisms
What was found after Brownlee examined the "space dust"?
minerals and carbon trials
In addition to living below the Earth's surface, where might have been another "safe haven" that protected the earliest life forms on Earth?
ocean
Because of the hostile environment and lack of food deep within the African mines, how often do bacteria found here divide?
one every thousand years
What important gas is produced as a waste product of photosynthesis?
oxygen
In addition to the oxygen allowing respiration to take place, what oxygen compound also protects us from harmful radiation?
ozone
3.6 billion years ago what process seems to have evolved utilizing the pigment chlorophyll?
photosynthesis
Amino acids are the building blocks of what molecules?
proteins
What were the "snottites found in these caves?
single celled bacteria
What surprising result did Jennifer Blank find?
the mixture transformed into peptides
How was "space dust" collected by scientist Don Brownlee?
using sticky pads on a former spy plane and flying it close to the edge of earths atmosphere
Briefly describe the conditions on this very early version of our Earth.
violent, lava, noxious gases, hot, reddish tint
Deep beneath the ocean, around what structures have seemingly ancient microbes been found growing?
volcanic vents