SBI 3U - UNIT 2 EVOLUTIONsciencerocksium.weebly.com/uploads/1/3/4/0/... · Stephen Hawkin: "A...
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SBI 3U - UNIT 2
EVOLUTION
“Nothing in biology makes sense except in the light of evolution.”
Theodosius Dobzhansky
Hypothesis - a tentative assumption made in order
to draw out and test _________________________
A hypothesis can be ____________________through
____________________. A hypothesis can be
_______________, but not _________________.
A scientific theory summarizes a ________________________
that have been supported with ____________________. A
theory is valid as long as _____________________________.
Therefore, theories can be ___________. Basically, if evidence
________________to support a hypothesis, then the
hypothesis can become ___________________________of a
phenomenon. One definition of a theory is to say it's an
_____________________________________.
Theory
Stephen Hawkin:
"A theory is a good theory if it satisfies two requirements: It must
accurately describe _____________________, and it must make
definite ______________ about the results of __________________."
"No matter how many times the results of experiments agree with
some theory, you can never be sure that the next time the result will
not contradict the theory. On the other hand, you can disprove a
theory by finding ______________________________________ with
the predictions of the theory."
Evolution Isn't Evolution Just a Theory
- Cell Theory
- General theory of relativity
-Wave theory of light
The theory of evolution and common descent ________________
_________________ in scientific circles.
This is ______________________. Debates continue about how
_______________of evolution work.
However, evolution is now a modern science and is ____________
_____________________________________________________
_____________________________________________________
Evolutionary Theory
Evolution - the process in which significant changes in ____________
_____________________________________
For centuries scientists have been making careful observations,
formulating and testing hypotheses, analyzing data from diverse
sources and have drawn inferences to develop the theory that is now
accepted as the solution to the puzzle of evolution.
Like all scientific theories _____________________of evolutionary
biology are based on __________________________and
interpretation __________________________________________.
History of Evolutionary Theory
Paleontology (systematic study of fossils)
•Began in the 18th century by _____________________.
•Cuvier made many discoveries including:
•Many fossils __________________________________!
•Fossils of simple organisms could be
_____________________
•Fossils of complex organisms were ______________________
•More recent fossils were more likely _____________________
•Each layer contained ___________________not found above
or below.
These findings puzzled Cuvier, as he did not believe ___________
________, he believed ___________________________.
He came up the theory of ______________________. He said that
local ____________________could cause widespread _________,
and new species would be _____________________________.
This could account for the ______________________in strata
layers, but it could not account for the ______________________.
The other problem for Cuvier was that there was no precise method
for ________________________________________________________
Age of the Earth
Radioisotopes are atoms that _____________________. These
atoms have an __________________________and will undergo
__________ to become ________ atoms.
(Isotopes have ______________________________________)
Ex. 235U decays into __________
14C decays into __________
It is the ______________that makes radioisotopes so valuable, because
the ___________________.
The time it takes for ________________________________is called the
_______________.
Ex.
Half-life is unaffected by ______________________ or other
environmental conditions.
With the discovery of Radioisotopes came the technique of _________________which
uses _______________________________________.
Ex. A sample of igneous rock contains small amounts of radioactive potassium and argon.
Using the ratio of 40Ar to 40K , it is determined that only 25% of the original parent
potassium isotope remains. How old is this rock sample?
1. A sample of igneous rock is found to contain the radioactive parent and daughter
isotopes uranium, 235U, and lead, 207Pb, in the ratio of 12.5%:87.5%. Assuming that
no 207Pb was present when the rock first formed, estimate the age of this sample.
2. A fossil skull of Homo neanderthalensis, is discovered in northern Europe and is
tested using carbon-14 dating. Palaeontologists are curious about whether the
Neanderthal was living at the same time as members of H. sapiens, thought to have
been living in the same area of northern Europe 45 000 years ago. Measurements
suggest that, of the original amount of carbon-14 isotope present in the skull when
the Neanderthal died, only 1.56% remains in the fossil fragment.
(a) How old is the fossil?
Using this type of dating the following has been found:
All meteorites to hit the earth have ________________________________.
Moon rocks have all been dated to about ________________________
Oldest rock on earth dated to ____________________________.
This leads us to believe that _____________________________________.