Download In determining who is more closely related to whom, or if 2 species

In determining who is more closely related to whom, or if 2 species are closely related, many scientific
practices are used. Below are the largest areas (disciplines) providing scientific evolutionary evidence. The
evidence tells the pattern of evolution and rate of separation of the species being studied.
1) Comparative anatomy – studying homologous, analogous and vestigial structures in different species
reveals common ancestry
2) Embryology – studying the development of organisms before they are born. EX: All vertebrates have gill
slits and a tail at one time in their embryo development.
3) Molecular Biology – studies the similarities and differences in organisms at the biochemical level. The
closer related 2 species are, the lower the percent different in any given biochemical. EX: comparing
things like; DNA sequences, number order and types of amino acids made, hemoglobin (the molecules
that carries O2 andCO2) and cytochrome C (proteins that assist organisms in breaking down food for
energy) reveals what species are closer than others based on how different or similar they are.
4) Paleontology – studies of fossils to determine information of extinct species and the formation of new
species, as well as a look at what our world was like as it was forming. EX: Fossil deposits of oyster shells
in the Grand Canyon walls indicate evidence about what our climate used to be like as well as gives
evidence of what prehistoric marine creatures were like.
Science uses combinations of the above in order to paint a clearer picture of organisms’ relationships. Now
that have introduced this concept, perform the following:
What parts of extinct organisms are well preserved in the fossil record? What parts are not?
What does inference have to do with fossils?
If you were using comparative anatomy to look at relatedness of 2 species, which of the 3 comparative
anatomy structures would you think would provide the most evidence for being closely related? Why?
Between species A and C the hemoglobin molecule shows a difference of 67%. Between species A and B
there is a 12% difference. Which 2 species are more closely related? Why? What type of science evidence is
this? Why do you have a tail bone, since there is no immediate function?
Name other vestigial structures in humans. Think of as many as you can!! 
Why are bee wings and bat wings not an indication of relatedness when they are both used for flight?
Match the term with the correct description:
1) _______ comparative morphology
2) _______ biogeography
3) _______ fossils
4) _______Hox gene
5) _______ species
6) _______ embryology
A) A group of individuals that can reproduce and have fertile
off spring.
B) The study of embryos as a clue to evolutionary
development.
C) The study of similarities and differences in body plans
D) Study of the world distribution of plants and animals
E) A defining characteristic of animals that tells cells how to
develop based on their location
F) Used now as evidence of life in ancient times.
The illustration below shows the bond in the forelimbs of some vertebrates. These limbs are drawn to
approximately the same scale. Study the illustration, and then answer the questions that follow.
Choose any 3 bones and color them the SAME color in the 6 different organisms.
How do the phalanges (finger bones) and metacarpals (hand bones) differ in these vertebrates?
How do the carpals (wrist bones) differ in the bat, human and horse?
How are these forelimbs similar?
How are homologous structures such as forelimbs evidence for common descent?
How are homologous structures such as forelimbs evidence for evolution?
Observe the following generalized stages of development for five organisms one row at a time. (Cover the
other rows with notebook paper)While the other rows are covered make your observations for each role and
answer the following questions:
1) Compare the vertebrate embryos in section I. Identify 2 specific ways they similar? Identify 2 specific ways
they are different?
2) Compare the vertebrate embryos in section II.Identify 2 specific ways they similar? Identify 2 specific
ways they are different?
3) Compare the vertebrate embryos in section III. Identify 2 specific ways they similar? Identify 2 specific
ways they are different?
4) Which section (row) shows the largest, overall DIFFERENCES?
Although this picture was used before technology really allowed scientists to study development, today, we
have the tools to confirm that as complex organisms go through embryological stages, we can see structures
that are NOT visible in the baby once it is born. Those “primitive” structures give a window into an animal’s
ancestry.
Log onto this site and read more about embryology and how it has been tweaked!
http://evolution.berkeley.edu/evolibrary/article/history_15
5) After you are done reading the web page above, explain why this statement is true.
“Although Ernst Haeckel was right, it took modern knowledge to truly make embryology a
scientifically accepted piece of evolutionary evidence.”
The information below shows amino acid sequences for a selected site on DNA of different vertebrates,
examine the sequences and answer the questions below:
HUMAN ser thr
ser thr
CHIMP
GORILLA ser thr
BABOON asn thr
ser ser
DOG
CHICKEN gln thr
asp ser
FROG
ala
ala
ala
thr
gly
gly
gly
gly
gly
gly
gly
gly
gly
gly
asp
asp
asp
asp
asp
ala
lys
glu
gly
gly
gly
glu
glu
his
val
val
val
val
ilu
ilu
val
glu
gly
gly
asp
asp
ala
thr
asp
asp
asp
asp
asp
asn
asn
thr
thr
thr
ser
thr
ser
ser
pro
pro
pro
pro
pro
pro
ala
gly
gly
gly
gly
ser
glu
his
gly
gly
gly
gly
asn
thr
ala
ala
ala
ala
asn
lys
lys
lys
asn
asn
asn
asn
asn
asn
asn
ala
ala
ala
ala
ala
ser
ala
thr
thr
thr
gln
ala
gln
lys
arg
arg
lys
lys
lys
arg
arg
his
his
his
leu
lys
ala
arg
1. On the basis of your observations, which 2 organisms are the closest in terms of amino acid sequence?
2. What is their (what you said above) % difference?
3. Which 2 primates (use your resources to assist you) are the most similar in their biochemistry? Support
your choice with data!
4. If the amino acids are different what large organic compounds change in the organism?
5. Which 2 organisms are the most different in their biochemistry? Support your choice using data.
6. Complete this sentence: “A higher rate of ancestry is evidenced by a _____(higher/lower) percent
difference in organism’s biochemistry
7. What conclusions can you draw about ancestry by examining the biochemical makeup of organisms?
8. Name 3 good biochemical molecules we can use in this technology.
Australia, Africa, and South America occupy the same latitude, at least in part, and therefore have roughly
the same climate. If plants and animals were distributed only according to their adaptations to habitat, we
would expect the same species to occupy similar regions of these continents. However, the short-tailed
monkeys, elephants, and lions in Africa differ significantly from the long-tailed monkeys, llamas, and
jaguars of South America, and even more from the koalas, kangaroos, and Tasmanian devils of Australia.
Biogeography studies the distribution of plants and animals and the processes that influence their
distribution – including evolution and natural selection. Only geologic change and evolution can explain the
distributions of many species, so biogeography is another kind of evidence for the theory of evolution.
Let’s consider just the camel family as an example, shown in Figure below of how biogeography explains the
distribution of species. Fossils suggest that camel ancestors originated in North America. Distant fossils show
structural similarities which suggest that their descendants migrated across the Bering land bridge to Asia
and across the Isthmus of Panama into South America. These two isolated populations evolved in different
directions due to differences in chance variations and habitat. Today’s descendants are llamas and guanacos
in South America, and camels in Asia. Asian camels continued to migrate west into Africa, giving rise to two
species – the dromedary in Africa, and the Bactrian in eastern Asia.
1. What pattern of evolution is
best supported by the data
provided above?
2. How is the fossil record used
to help support biogeography?
3. So you are a paleontologist
and find fossils you hypothesize
it is from an ancient, extinct
camel that is the ancestor to
modern camels. Using
information from the class
“evidence lecture” identify one
way you could support your
hypothesis.