4. Pacdomurphosis restlis from an accelerabed development of the reproductive aystem relative to the ros: of the body. The anal growth stages are climirsted in the proces. Btz, it there is selective pressure to arley the onset of reproductive maturity, thew growth stages may actilly be added ae a consequenoe ot evoitition. A. Add the next growth stage to the serits given betow to show this deiayed maturation effect at geologic time 2. If the selective pressure were to continde, show the eftocts at getologic time 3, An this exampie sexual maturity should be reacned at the final grewth stage). Geologic Time 3 Geologic Time 2 Geologic Time 1 A B C D E B. Mamy organiame grow by sively secreting mote skeletal materai at the growih margin. Their shapt may change producing differert growth stages. Brachiopods. tivalvea, and oephalopods are somen comr mon examples of tide kind of arcretionary growth One usc ful ronsequence of this style of growth it that a record is kept of the former growth atages. Assume thai the fogsil taxs shown here grew by accretionary growth. Explain how you couid use the recxided growth atages in the tavon shown a geologic time 3 to determint its ancestors ever it yoet did not have fossils from geologic time 2 of geologic time 1 . 3. The tossil recoed of mast vertebeates is sparse, as comparec with that of marine invertebeztes, because o the nature of the bxast. Many taphonomic processes interast in prevent most terrestral vertebratez trou secoming fossilized. The fist, an the other hand is a group of verteptaieg that live in an acualicidepo sitionall environment. The group is composed (for the most pert) of organisnts with mineralized skele tocs, and possesses a high potentinl for focsilization. If is no wonder that this vertekinise igroup tas a gooc. foedil record. A. The following graph depicts the zates of or.giration and extinction for familiet of Phaneposoic fish ise member that families are compoded of anany genese in wheh there are marry cifferent speciesi 7 to rate of angimation represents origination tate the number of families that appcared during ead gtratigraptic stage divided by the estimated sige duration: divided by the end-of-atage family ci vessity; the rite of extinction retreserts the extinction rate divided by the end-ol-5tage family diver city. This vasue can be sised as a measune ot the "probabizty of origin" or the "risk of extinction." 2. Evolutiorvary theory predicis that crganisms should appear in a scquence over time, and that it ahoutd be possible to tink younger forms to elder ferme The model of "punctoalec equilibrium" prechets that rew torms (epecies) mhould etten appeas "suddenly" and then experience iang periods of stasis for stagnationj. The model of "phyletic gradualism" predicts that mest speries ahould chnnge gradually thoughout time, and many apecies-torspecies transitione vill be part of the record. Several terms, ate usec to describe the mechanisms invoived in these models. Anagenesis .

1. 4. Pacdomurphosis restlis from an accelerabed development of the reproductive aystem relative
to the ros: of the body. The anal growth stages are climirsted in the proces. Btz, it there is
selective pressure to arley the onset of reproductive maturity, thew growth stages may actilly be
added ae a consequenoe ot evoitition. A. Add the next growth stage to the serits given betow to
show this deiayed maturation effect at geologic time 2. If the selective pressure were to continde,
show the eftocts at getologic time 3, An this exampie sexual maturity should be reacned at the
final grewth stage). Geologic Time 3 Geologic Time 2 Geologic Time 1 A B C D E B. Mamy
organiame grow by sively secreting mote skeletal materai at the growih margin. Their shapt may
change producing differert growth stages. Brachiopods. tivalvea, and oephalopods are somen
comr mon examples of tide kind of arcretionary growth One usc ful ronsequence of this style of
growth it that a record is kept of the former growth atages. Assume thai the fogsil taxs shown
here grew by accretionary growth. Explain how you couid use the recxided growth atages in the
tavon shown a geologic time 3 to determint its ancestors ever it yoet did not have fossils from
geologic time 2 of geologic time 1 . 3. The tossil recoed of mast vertebeates is sparse, as
comparec with that of marine invertebeztes, because o the nature of the bxast. Many taphonomic
processes interast in prevent most terrestral vertebratez trou secoming fossilized. The fist, an the
other hand is a group of verteptaieg that live in an acualicidepo sitionall environment. The group
is composed (for the most pert) of organisnts with mineralized skele tocs, and possesses a high
potentinl for focsilization. If is no wonder that this vertekinise igroup tas a gooc. foedil record.
A. The following graph depicts the zates of or.giration and extinction for familiet of Phaneposoic
fish ise member that families are compoded of anany genese in wheh there are marry cifferent
speciesi 7 to rate of angimation represents origination tate the number of families that appcared
during ead gtratigraptic stage divided by the estimated sige duration: divided by the end-of-atage
family ci vessity; the rite of extinction retreserts the extinction rate divided by the end-ol-5tage
family diver city. This vasue can be sised as a measune ot the "probabizty of origin" or the "risk
of extinction."
2. Evolutiorvary theory predicis that crganisms should appear in a scquence over time, and that it
ahoutd be possible to tink younger forms to elder ferme The model of "punctoalec equilibrium"
prechets that rew torms (epecies) mhould etten appeas "suddenly" and then experience iang
periods of stasis for stagnationj. The model of "phyletic gradualism" predicts that mest speries
ahould chnnge gradually thoughout time, and many apecies-torspecies transitione vill be part of
the record. Several terms, ate usec to describe the mechanisms invoived in these models.
Anagenesis is the idea that an oicier species, as a whoie, changes into a new descendent species.
in effect, the ancestor is transiormed inoo the descencient. Cladogenesis is the concept that a
daughber ppecies splia oet form a population of an vicie species, after which both the oid and

2. new apedies coexist in time (and possibly spacci. A chronocline is defined as the graduai change
in one lineage over time. A. Examine the two lineages of "fossil" sutomobiles over the past co
years. Can you identify any "spedation events" in ether lineage? If ac, mark each spedation event
by deawing ol line acrose the auto lineage at the appropriate level of tinange. B. How many
speciabion events can you identify within the VW' lineage? C. How many speciation events can
you identify within the Mustang linesge? D. What is the rate frumser of epeciation events ftimel
of evelutionaty change in the VW linenge? E. What is the rate of evolutionary charge in the
Mustang lineage? F. Which evoluticnary madel best describes the danget, or lack thereve, in the
VW tineage? G. Which ewelutionary model best describes the changes documented in the
Mugang lineage? H. Which of the following evolutionary mecharisms wou'd best apply when
describing the Mustang linegge? (Aragenesis) (Chaciogivesia) (Chronocline)
EXERGISES 1. The long-term effects of selective preesures on populations of organisms can be
seen oniy in the fossil resord because of the amounts of time involved. But sedimentation and
fossilization are spotty in terms of geographic as well as chronologic distribution. This makes
reconstructing evoiutionary histories and testing concepts such as punctuated equilibria very
difiscult. A. The data points plotted below represent the average of many measuremenis made on
some morphologic chatacter (e.gs, width of shell) at different geoiogic times, in order to
illustrate the evolutionary history of the fossil taxa shown, the data points muat be connected by
lines representing the missing intermediary steps. In figure A, connect the data points using the
model known as phyletic graduaiism. In doing so, show one speciation event and label it as such.
B. In Egare B, using exactiy the same ciata, cornect the points by lines uing the punctuated
equilibrium model. Show and linei two rapid speciation cvents and a lineage exhibiting stasis. C.
Do the availajle data allow you to reject one of these modeis in faver of the otiner for this
particular case? (IES) (NO) D. If not, what kind of additional data would be recuired to do 5o?
4. Paedomorphosis resuls from an accelerated development of the reproductive system telative to
the rest of the body. The final growth stages are eliminated in the process. But, if there is
selective pressure to de: lay the onset of reproductive maturity, new growth stages may actually
be added as a consequerice of evo. lution. A. Add the next growth stage to the series given below
to show this delayed maturation effect at geologic time 2. If the selective pressure were to
continue, show the effects at geologic time 3 . (In this example sexual maturity should be
reached at the final growth stage). B. Many organisms grow by simply secreting more skeletal
material at the growth margin. Their shape may change, producing different growth stages.
Brachiopods, bivalves, and cephaiopods are some com mon examples of this kind of
accretionary growth. One useful consequence of this style of growth is that a record is kept of the

3. former growth stages. Assume that the fossil taxa shown here grew by accretionary growth.
Explain how you could use the recorded growth stages in the taxon shown a geologic time 3 to
determine its ancestors even if you did not have fossils from geologic time 2 o: geologic time 1.