Ch. 10 Test Review: Clues to Earth's Past
Brought to you by Cy Marchant
Umm-False. One's false-not rare. Needs to be-
it's rare then it-can't be-you won't
find it. Okay-after one half-life it's
not going to be 25% it'd be 50%, so that's false.
Three: false, because carbon doesn't go
back as far as the age of the earth so
they've all been "false" so far, haven't they.
But four is true. Four is true. The youngest
is on the top; oldest on the bottom. Five: no that's
not uniformitarianism so it's false.
It's law of horizontality, I think. Six: the
remains of living? ahh-what do you think
about that one? It wouldn't be living, would it be?
False. 7: that's false.
It's not absolute age, that would be uh-
relative age. 8: 8 is true. 8 is true. 9:
...are the remains of species that existed on earth
for a relatively short- yeah, cuz if they're during a
short period of time that's why they can
be used for an index. That's true. 9's true.
10: no, the footprints aren't original
remains,
they're called trace; which is the traces
of them. The original would be like the
bones or something. Okay; you know those? -unknown- Okay:
Use the graph - half-life of thorium, so,
right there's the half-life, so then you
just go to the time. It says 14, so
there's your answer.
Okay what would it be if I put two
half-lives here now? Okay-so two
half-lives: you're gonna go right there:
that's 28 You can see each time
it's 14. 14. 14. It's kind of showing-it's
not important, but you get the idea. Okay, look at those.
Altered hard parts. Altered hard parts
would be-would be-it's (A) that's what
petrified wood is. For dating use the 
properties of and atoms and rocks to find their
ages okay that would be absolute dating.
Four is absolute. Four-I mean-sorry, five:
The principle of superposition is used to determine:
(B) the relative age of the rock layers, so
it's (B) Five's (B). Okay-six: this is
half-life-six is half-life. Seven:
characteristics of radioactive decay
makes it useful determine the absolute
age of samples-mmm-it's constant rate
seven is: (C) constant rate. Umm-the oldest rock
layer is going to be: at the bottom the
sequence (D) 9: what would change to represent
the isotope? The mass. The mass is what we change. Okay. Everything else would stay the
same but the mass. Seven. Seven was: occurs at a constant rate-the oldest is at the
bottom. Okay look at those. -unknown-
That is relative dating, is number 10.
Number 11: Umm-rock layers are correlated if
they both contain-oh, I would say
fossils. You guys agree with that? 'kay. 11:
fossils. 12: radiocarbon dating is used to
determine the age of what type material?
So it's radiocarbon; it's if it's carbon
is in living organisms.
I mean, well,
it is, but the-umm-I'd say no organic
materials is a better answer, because it
can't be still living because then the
radiocarbon stays the same. 13:
Hardened tree sap is amber. D'you guys
remember the first Jurassic Park? Okay, it
was amber where they found that
dinosaur DNA, inside the insects in the amber. (That's an old movie.)
It IS old; it's like twenty seven or
eight years old now fourteen where
statement is not true regarding the
Earth's past climate is not true hmm
it's a Earth's climate is say the same
it's not true fifteen what
classification occurs with seven each
Rock overlies igneous rock which one is
that
it's an unconformity which one is that
15 is non-conformity okay says right
here younger sedimentary rock on older
igneous rock is not what that and says
okay example of fossil or original
preservation okay so it means if the
actual organism is preserved it's the
only one that's an actual organism is D
okay footprint copyrights dinosaur poop
that's what it is
okay multicast trace are all examples of
fossils aren't they
okay what belongs in the Box it's this
one pressure moves all gases and liquids
from the organisms tissue so basically
anything that wasn't carbon gets a
pressed away and the carbon of the body
just what's left leaves a little imprint
17 bulbs or fossils types of fossils 15
that's the nonconformity one
16 is the insect is the actual fossil
spark of carbon 14 is way to measure the
age of the remains of organisms K work
correctly describes one limitation see
don't see hi
it's a so it's only 5700 so after six or
seven half lakhs which isn't even - even
isn't it like 50000 years there's not
enough of it to trace okay so it's
really if it's over 50,000 years then
it's too old can't trace it using
radiocarbon twenty index also are useful
if the fossils you think it's C have
lived over short period of time yep yeah
it's see the one when original parts and
organisms are weather and eroding
hollowed out an impression
what's the hollowed out impression mold
yeah that's two forms when hollowed out
impressions cast yeah just wants mold
and cast with those old turned by
examining position of rocks in sequence
that's some relative dating is that up
there yeah that's what it is
two States you're understood rocks
oldest rocks that's gonna be super
position let's should be if there isn't
next one three fossil form when outline
is formed from leftover carbon well that
should be carbon film free is a carbon
field or is index fossil five time takes
for half of the isotope that's half-life
and six states the Earth's process today
that's uniformitarianism which is I
don't go over any of those again
six uniformitarianism for index fossils
the others less pay Ferguson's they're
likely to become fossils hard okay like
a bones that type of stuff shells eight
fossils 50 meters up to that's carbon-14
fossils are we what would that be
trace remains oh yeah remains yep okay a
blank may tell what paleontologists win
where how what's that one that's trace
trace fossil prom date yeah he's
measuring half-life okay he knows
you know the radioactive element has
massive eighty grams how much parent
will have to half way so you're just
gonna divide that by two twice so you
got to buy the 80 by two twice okay
which I stopped well know how to do it
because might not be the same number
right there
tell me just know how to do it which I
still be most helpful in dating bones be
about six thousand years old so probably
gonna be that one yeah because it's
these are too way too old which ice
