Download Molecular and Morphological Homologies PPT File

BELL RINGER
1. What is the difference between
these two types of speciation
paths?
2. What is indicated by the straight
horizontal lines in the
Punctuated graph? (why doesn’t
the Gradual graph have those?)
3. What is indicated by the straight
vertical lines in the Punctuated
graph?
3/23/17
Today we are going to focus on
Molecular and Morphological homologies
as evidence of evolution.
• Homology is similarity resulting from common ancestry.
MOLECULAR HOMOLOGIES
All living things have A,T,C,G in their DNA
and ALMOST ALL organisms use the same codon chart to code for the
same amino acids.
This chart is showing
how similar a certain
protein is between
various organisms.
(The hemoglobin
protein)
Molecular Homologies
Scientists have sequenced the DNA of organisms to find similarities.
The closer the sequencing in DNA of organisms, the more closely they are related.
The more closely related, the more recent of a common ancestor they share.
The biochemistry (DNA) of a bat is much
closer to that of a whale, than that of a
bird.
Why?
The same technology used to determine
paternity can be done to determine
shared ancestry.
Because bats and whales are
mammals!
Therefore, more closely
related…..
Bat
Whale
Bird
One form of evidence in the unity of life…..
Morphological evidence
FORM
AND
STRUCTURE
Science sees detailed structural similarities as evidence
that organisms evolved from a common ancestor.
Homologous
parts are
similar in
structure, but
may be very
different in
specific
function.
Similar structural features because of a common
evolutionary origin are called homologous structures.
Vestigial Structures
These are structures that used to have a function, but
no longer do….therefore suggesting evolution based
VIDEO
on new behaviors or environments
Embryology is the study of organisms in embryonic stages.
The embryo is one of the earliest stages of growth and development of
both plants and animals.
The shared
features in the
embryos of
vertebrates
suggests
evolution from a
distant common
ancestor.
Shared Common Features:
• a tail posterior to the anus
• spinal cord
• muscles arranged in bundles
• cartilage dorsal notochord (becomes the vertebral column)
• Pharyngeal gill slits
QUESTION: DISCUSS WITH YOUR GROUP:
If you had two organisms in your lab with similar looking
features, how could you find out if these structures are
homologous or analogous?
https://www.youtube.com/watch?v=P3GagfbA2vo
CRASH COURSE
VIDEO IN
EVOLUTION