Origin
of
Life
Instructions: watch the mini-lecture (14 min)
https://youtu.be/SWY3FKbtEz8 (Boseman origin of life –
scientific evidence). Answer the following questions.
1. Approximately how old is the Earth?
The earth is approximately 4.55 billion years old.
2. When do scientists estimate that LIFE first began on
Earth?
Life first began on earth around 3.8 billion years ago.
3. List 2 types of evidence we have to support the origin
of life.
The earth was too hot, being bombarded with molten
materials from space and within, to support life until
around 3.8b years ago. Stromatolites are fossils found
of bacteria, which rock dating revealed to be around
3.8b years ago as well.
4. How did photosynthesis affect early Earth? (In terms of
how it changed the atmosphere and how it affected
organisms).
Photosynthesis began pumping O2 into the
atmosphere, which had none to begin with. With a
now O2 rich atmosphere, more organisms that are
able to use it to survive, eukaryotes, evolve into
existence.
5. When did multicellular eukaryotes first appear?
When the atmosphere had enough O2 for long
enough to constantly support them.
6. Briefly describe the Miller-Urey experiment.
An attempt to replicate the early atmosphere of the
earth with water, methane, ammonia, carbon
monoxide, and hydrogen gas. They added energy in
the form of lightning and collected the molecules that
resulted from it, finding a potential origin of amino
acids.
7. What is the difference between extinct and extant life
forms?
Extinct life forms are those which do not exist on this
planet anymore. Extant life forms are those that do.
8. What characteristics does all of life on Earth share with
earth other and our last common ancestor?
The use of DNA, RNA, proteins, and other
macromolecules for cellular function.