Transcript So…What do we know about evolution?

Evidences of
Evolution
1) Fossil Evidence
a. Fossils are remains or traces of
organisms that died long ago, often
found in layered rock (strata).
b. If undisturbed, the lowest
oldest and
stratum is the ______
the highest stratum is the
newest
_______.
Relative age of fossils is
c. __________
found by comparing ages of
strata.
Absolute age is found by
d. ___________
using radiometric dating.
e. Fossil record
suggests that
different species
were present in
the past than
today.
f. Gradualism:
i. Evolution occurs slowly and
continuously throughout
time.
ii. Fossil record should show
many transitional species,
but it doesn’t.
g. Punctuated Equilibrium
i. Proposed by Stephen Gould.
 For long periods of time, the
existing species didn’t ________
change
(equilibrium). Then, in relatively
short periods of time, there is an
interruption in the equilibrium,
and new species emerge. The
_____
______ seems to support
fossil record
this, but the mechanism is
uncertain.
2) Anatomy
Study of parts or structures
of living things.
a. Homologous Structures:
internal parts, but
Similar ________
function in
different _______
different creatures.
i. Suggests descended from
common ancestors.
ii. Examples: human arm, cat
leg, whale fin, bat wing.
Example of Homologous Structures
What do you notice about these structures?
And these?
b. Analogous Structures: Similar
external forms and
________
functions, but different
internal forms and functions.
_______
i. Suggests species came from
different ancestral lines.
ii. Example: bird wing and
insect wing
Analogous Structures
What do you notice about these structures?
c.
Vestigial Structures:
reduced in size and
usually _______
have no function.
i. Suggests that structure was
once used by evolutionary
ancestor.
ii. Example: human appendix,
human ear muscles
3) Embryology
a.
b.
Study of embryos as they
develop.
Similarities of embryos
___________
during development suggests
that species _______________
share a common
_______
ancestor.
4) Molecular Evidence:
a.
We can analyze chemical
similarities between living
things.
b. DNA comparison: The
more DNA in common,
closer the
the _______
relationship between
organisms.
a. Protein Comparison: Similarities
amino acid that make
of __________
proteins suggests relationship
between organisms
i. Example: In proteins, cytochrome
___________
c,
the difference between amino
acids…
1. Humans vs. monkeys: 1
2. Humans vs. pig: 10
Evidence From Living
Creatures
Anatomical
Similarities
Embryological Similarities
Molecular Similarities