Learn About
EVOlutionary relationships among
organisms using the Evidence of
Evolution
12 - STEM B
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We can infer evolutionary relationship
among organisms using the evidence of
evolution through the following evidences:
FOSSIL EVIDENCE
COMPARATIVE ANATOMY
BIOCHEMICAL EVIDENCE
BIOGRAPHY
EMBROYOLOGICAL EVIDENCE
2 TYPES OF
EVIDENCES
DIRECT
&
INDIRECT EVIDENCES
Direct evidence
Can be
directly
observed or
seen
indirect evidence
does not involve
actual observation
of evolution but
from which
evolution may be
inferred
FOSSILS
Fossils are the preserved remains of
plants and animals whose bodies
were buried in sediments, such as
sand and mud, under ancient seas,
lakes and rivers. Fossils also include
any preserved trace of life that is
typically more than 10 000 years old.
However the information obtained
from fossil is relatively incomplete
for several reasons.
1. Only a small number of fossils are found;
2. Soft tissues are rarely preserved;
3. Most fossils have been destroyed by erosion, and
or/ movement of the earth’s crust may have caused
some fossils to be buries deeply; and
4. Fossilization takes place only in places where
conditions are favorable.
How do
paleontologists
determine how
old a fossil is?
RELATIVE DATING METHOD –
the approximate age of a fossil can be
determined by comparing fossil positions in
the layers of rocks.
ABSOLUTE DATING METHOD or radiometric
relies on the decay of certain radioactive
elements in the earth’s crust.
COMPARATIVE ANATOMY
The comparing of
anatomical
structures within
a particular group
of organisms
reveals a unity of
plan among those
that are closely
related.
Homologous structures: are body
structures of different organisms
that have the same basic arrangement
and pattern of embryonic
development.
Analogous structures: Have similar
function but differ in appearance.
Vestigial Structures: are parts of the
body without a particular function.
Like vermiform appendix, third molars.
In snakes, have skeletal limbs but it has
no used to them.
GENETICS AND MOLECULAR BIOLOGy
The bodies of all living species
on this planet contain many of
the same biochemical
molecules, including DNA, ATP,
amino acids, and enzymes.
BIOGEOGRAPHY
the study of the distribution of
organisms.
Darwin's Voyage on
"THE BEAGLE" at "Galapagos Island"
NOTOCHORD & PAIR PHARYNGEAL SLITS
EMBRYOLOGY
There are remarkable similarities in the
embryonic development of all vertebrates that
support Darwin’s idea of common descents.
What do some scientists infer from this?
They infer that an organism passes some of the
embryonic stages that its ancestors went
through. Then modifications happen in the later
stages of development in accordance with what
will be the organisms final form.
12 - STEM B
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12 - stem b
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