Bio Exam 1 Tutorial 2

Tutorial 1 Bio Exam 1

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How old is Earth and how do we know?
4.55-4.56 billion years old. We know this because astronomers have done radiometric dating...
how old is the universe and how do we know?
the universe is 13.7 billion years old and we know this because astronomers have measured trajectories...
What chemicals were in early Earth's atmosphere and why was this beneficial to forming life?
Methane, ammonia, water vapor, and hydrogen. this was beneficial for life because the early...
why would oxygen make life impossible in the beginning?
life could not arise from inorganic compunds if oxygen was present in the beginning because...
What is the primordial soup model?
This model suggests that the origin of life arose from the right ratio of chemicals mixed...
What was the Miller-Urey experiment?
This experiment simulated early earth by isolating hydrogen, ammonia, methane, and water vapor,...
What were the first cells on Earth like?
autotrophs that gained energy from inorganic compounds like sulfur and iron compounds.
describe plate tectonics and their implications.
the fact that the Earth's crust is broken into pieces. the crashing/touching/rubbing of plates...
what is pangea and how many years ago did it exist?
Pangea was Earth's supercontinent that existed 250 million years ago. about 180 million years...
what is the evidence for the existence of Pangea?
South America and African coastlines fit togethersimilar plant and animal fossils were found...
What are the four great eras of the geological time scale? (oldest to newest)
Precambrian, paleozoic (origin of most modern animal phyla), mesozoic, cenozoic (we are in...
What is relative dating?
when sedimentary rock forms, layers pile on top of layers. a layer is called a stratum. fossils...
What is an isotope?
the same atom with a different number of neutrons.
describe radiometric dating.
radioactive isotopes decay into more stable elements at predictable rates. scientists use half...
Describe radiocarbon dating. How many years have to go by before is it no longer accurate?
Carbon-14 decays into Nitrogen-14. Results are no longer valid after 50,000 years.
What is dendrochronology?
absolute dating technique. One ring is produced on a tree each year. by matching tree growth...
How many species have we documented on earth?
1.8 million documented species 
What are the three domains of life and which ones are prokaryotic
bacteria, archaea, and eukaryotes. Bacteria and archaea are prokaryotic.
How many species to we estimate to exist on earth
between 10-100 million

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