Originally posted by Deist27
natural selection acts as a sieve which eliminates weaklings or those with incomplete structures (arms, legs, eyes, etc.) that may have arisen because of mutations.
Once again... just repeating yourself
Transitory fossils have NEVER been found. Show us a single one.
How about these?
taken from
here
This link has other ape->human skulls and shows that even creationists can not tell decide if the transitional fossils are more ape or more human.
taken from
here
And finally from
here :
<ul>
Transition from primitive jawless fish to sharks, skates, and rays:
<ul>
<li>
Cladoselachians (e.g., <i>Cladoselache</i>).
<li>
Hybodonts (e.g. <i>Hybodus</i>)
<li>
Heterodonts (e.g. <i>Heterodontus</i>)
<li>
Hexanchids (e.g. <i>Chlamydoselache</i>)
</ul>
Transition from primitive bony fish to holostean fish:
<ul>
<li>
Palaeoniscoids (e.g. <i>Cheirolepis</i>); living chondrosteans such as
<i>Polypterus</i> and <i>Calamoichthys</i>, and also the living acipenseroid
chondrosteans such as sturgeons and paddlefishes.
<li>
Primitive holosteans such as <i>Semionotus</i>.
</ul>
Transition from holostean fish to advanced teleost fish:
<ul>
<li>
Leptolepidomorphs, esp. <i>Leptolepis</i>, an excellent holostean-teleost
intermediate
<li>
Elopomorphs, both fossil and living (tarpons, eels)
<li>
Clupeomorphs (e.g. <i>Diplomystus</i>)
<li>
Osteoglossomorphs (e.g. <i>Portheus</i>)
<li>
Protacanthopterygians
</ul>
Transition from primitive bony fish to amphibians:
<ul>
<li>
Paleoniscoids again (e.g. <i>Cheirolepis</i>)
<li>
<i>Osteolepis</i> -- one of the earliest crossopterygian lobe-finned fishes,
still sharing some characters with the lungfish (the other group of
lobe-finned fish). Had paired fins with a leg-like arrangement of bones,
and had an early-amphibian-like skull and teeth.
<li>
<i>Eusthenopteron</i> (and other rhipidistian crossopterygian fish) --
intermediate between early crossopterygian fish and the earliest
amphibians. Skull very amphibian-like. Strong amphibian-like backbone.
Fins very like early amphibian feet.
<li>
Icthyostegids (such as <i>Icthyostega</i> and
<i>Icthyostegopsis</i>) --
Terrestrial amphibians with many of <i>Eusthenopteron</i>'s fish features
(e.g., the fin rays of the tail were retained). Some debate about
whether <i>Icthyostega</i> should be considered a fish or an amphibian;
it is an excellent transitional fossil.
<li>
Labyrinthodonts (e.g., <i>Pholidogaster</i>, <i>Pteroplax</i>) -- still have some
icthyostegid features, but have lost many of the fish features (e.g.,
the fin rays are gone, vertebrae are stronger and interlocking, the
nasal passage for air intake is well defined.)
</ul>
Transition from amphibians to reptiles:
<ul>
<li>
Seymouriamorph labyrinthodonts (e.g. <i>Seymouria</i>) -- classic labyrinthodont
skull and teeth, with reptilian vertebrae, pelvis, humerus, and digits;
amphibian ankle.
<li>
Cotylosaurs (e.g. <i>Hylonomus</i>, <i>Limnoscelis</i>) -- slightly amphibian
skull (e.g. with amphibian-type pineal opening), with rest of skeleton
classically reptilian.
<li>
The cotylosaurs gave rise to many reptile groups of tremendous variety. I
won't go into the transitions from cotylosaurs to the advanced anapsid
reptiles (turtles and possibly mesosaurs), to the euryapsid reptiles
(icthyosaurs, plesiosaurs, and others), or to the lepidosaurs (eosuchians,
lizards, snakes, and the tuatara), or to most of the dinosaurs, since I don't
have infinite time. Instead I'll concentrate on the synapsid reptiles (which
gave rise to mammals) and the archosaur reptiles (which gave rise to birds).
</ul>
Transition from reptiles to mammals:
<ul>
<li>
Pelycosaur synapsids -- classic reptilian skeleton, intermediate between
the cotylosaurs (the earliest reptiles) and the therapsids (see next)
<li>
Therapsids (e.g. <i>Dimetrodon</i>) -- the numerous therapsid
fossils show gradual transitions from reptilian features to
mammalian features. For example: the hard palate forms, the teeth
differentiate, the occipital condyle on the base of the skull doubles,
the ribs become restricted to the chest instead of extending down the
whole body, the legs become "pulled in" instead of sprawled out, the ilium
(major bone of the hip) expands forward.
<li>
Cynodont theriodonts (e.g. <i>Cynognathus</i>) -- very mammal-like reptiles.
Or is that reptile-like mammals? Highly differentiated teeth (a classic
mammalian feature), with accessory cusps on cheek teeth; strongly
differentiated vertebral column (with distinct types of vertebrae for
the neck, chest, abdomen, pelvis, and tail -- very mammalian), mammalian
scapula, mammalian limbs, mammalian digits (e.g. reduction of number of
bones in the first digit). But, still has unmistakably <b>reptilian</b>
jaw joint.
<li>
Tritilodont theriodonts (e.g. <i>Tritylodon</i>,
<i>Bienotherium</i>) -- skull
even more mammalian (e.g. advanced zygomatic arches). Still has
reptilian jaw joint.
<li>
Ictidosaur theriodonts (e.g. <i>Diarthrognathus</i>) -- has all the mammalian
features of the tritilodonts, and has a <b>double</b> jaw joint; both the
reptilian jaw joint and the mammalian jaw joint were present, side-by-side,
in <i>Diarthrognathus</i>'s skull. A really stunning transitional fossil.
<li>
Morganucodonts (e.g. <i>Morganucodon</i>) -- early mammals. Double jaw joint,
but now the mammalian joint is dominant (the reptilian joint bones are
beginning to move inward; in modern mammals these are the bones of
the middle ear).
<li>
Eupantotheres (e.g. <i>Amphitherium</i>) -- these mammals begin to show the
complex molar cusp patterns characteristic of modern marsupials and
eutherians (placental mammals). Mammalian jaw joint.
<li>
Proteutherians (e.g. <i>Zalambdalestes</i>) -- small, early insectivores with
molars intermediate between eupantothere molars and modern eutherian
molars.
<li>
Those wondering how egg-laying reptiles could make the transition to
placental mammals may wish to study the reproductive biology of the
monotremes (egg-laying mammals) and the marsupials. The monotremes
in particular could almost be considered "living transitional fossils".
[see Peter Lamb's suggested marsupial references at end]
</ul>
Transition from reptiles to birds:
<ul>
<li>
<i>Lisboasaurus estesi</i> and other "troodontid dinosaur-birds" -- a bird-like
reptile with very bird-like teeth (that is, teeth very like those of
early toothed birds [modern birds have no teeth]). May not have been
a direct ancestor; may have been a "cousin" of the birds instead.
<li>
<i>Protoavis</i> -- this is a <b>highly controversial</b> fossil that may or may not be
an extremely early bird. Not enough of the fossil was recovered to
determine if it is definitely related to the birds, or not. I mention it
in case people have heard about it recently.
<li>
<i>Archeopteryx</i> -- reptilian vertebrae, pelvis, tail, skull, teeth, digits,
claws, sternum. Avian furcula (wishbone, for attachment of flight
muscles), forelimbs, and lift-producing flight feathers. <i>Archeopteryx</i>
could probably fly from tree to tree, but couldn't take off from
the ground, since it lacked a keeled breastbone (for attachment of large
flight muscles) and had a weak shoulder (relative to modern birds).
<li>
"Chinese bird" [I don't know what name was given to this fossil] --
A fossil dating from 10-15 million years after <i>Archeopteryx</i>.
Bird-like claws on the toes, flight-specialized shoulders, fair-sized
sternal keel (modern birds usually have large sternal keel); also
has reptilian stomach ribs, reptilian unfused hand bones, & reptilian
pelvis. This bird has a fused tail ("pygostyle"), but I don't know how
long it was, or if it was all fused or just part of it was fused.
<li>
"Las Hoyas bird" [I don't know what name was given to this fossil] --
This fossil dates from 20-30 m.y. after <i>Archeopteryx</i>. It still
has reptilian pelvis & legs, with bird-like shoulder. Tail is
medium-length with a fused tip (<i>Archeopteryx</i> had long, unfused tail;
modern birds have short, fused tail). Fossil down feather was found with
the Las Hoyas bird.
<li>
Toothed Cretaceous birds, e.g. <i>Hesperornis</i> and <i>Ichthyornis</i>. Skeleton
further modified for flight (fusion of pelvis bones, fusion of hand
bones, short & fused tail). Still had true socketed teeth, which are
missing in modern birds.
<li>
[note: a classic study of chicken embryos showed that chicken bills can
be induced to develop teeth, indicating that chickens (and perhaps other
modern birds) still retain the genes for making teeth.]
</ul>
</ul>
<p>
Now, on to some of the classes of mammals.
<ul>
Transitional fossils from early eutherian mammals to primates:
<ul>
<li>
Early primates -- paromomyids, carpolestids, plesiadapids. Lemur-like
clawed primates with generalized nails.
<li>
<i>Notharctus</i>, an early Eocene lemur
<li>
<i>Parapithecus</i>, a small Old World monkey (Oligocene)
<li>
<i>Propliopithecus</i>, a small primate intermediate between <i>Parapithecus</i>
and the more recent O.W. monkeys. Has several ape-like characters.
<li>
<i>Aegyptopithecus</i>, an early ape.
<li>
<i>Limnopithecus</i>, a later ape showing similarities to the modern gibbons.
<li>
<i>Dryopithecus</i>, a later ape showing similarities to the non-gibbon apes.
<li>
<i>Ramapithecus</i>, a dryopithecine-like ape showing similarities to the
hominids but now thought to be an orang ancestor.
<li>
<i>Australopithecus</i> spp., early hominids. Bipedal.
<li>
<i>Homo habilis</i>.
<li>
<i>Homo erectus</i>. Numerous fossils across the Old World.
<li>
<i>Homo sapiens sapiens</i>. This is us. (NB: "Cro-magnon man" belongs
here too. Cro-magnons were a specific population of modern humans.)
<li>
<i>Homo sapiens neanderthalensis</i> (not on the direct line to <i>H. sapiens
sapiens</i>, but worth mentioning).
<li>
[I haven't described these fossils in detail because they're fairly well
covered in any intro biology text, or in any of several good general-
interest books on human evolution.]
</ul>
Transitional fossils from early eutherian mammals to rodents:
<ul>
<li>
Paramyids, e.g. <i>Paramys</i> -- early "primitive" rodent
<li>
<i>Paleocastor</i> -- transitional from paramyids to beavers
<li>
[yick. I was going to summarize rodent fossils but <i>Paramys</i> and its
friends gave rise to 5 enormous and very diverse groups of rodents, with
about ten zillion fossils. Never mind.]
</ul>
Transitional fossils among the cetaceans (whales & dolphins):
<ul>
<li>
<i>Pakicetus</i> -- the oldest fossil whale known. Only the skull was found.
It is a distinct whale skull, but with nostrils in the position of a
land animal (tip of snout). The ears were <b>partially</b> modified for
hearing under water. This fossil was found in association with fossils
of land mammals, suggesting this early whale <b>maybe</b> could walk on land.
<li>
<i>Basilosaurus isis</i> -- a recently discovered "legged" whale from the
Eocene (after <i>Pakicetus</i>). Had hind feet with 3 toes and a tiny remnant
of the 2nd toe (the big toe is totally missing). The legs were small and
must have been useless for locomotion, but were specialized for swinging
forward into a locked straddle position -- probably an aid to copulation
for this long-bodied, serpentine whale.
<li>
Archaeocetes (e.g. <i>Protocetus</i>, <i>Eocetus</i>) -- have lost hind legs entirely,
but retain "primitive whale" skull and teeth, with forward nostrils.
<li>
Squalodonts (e.g. <i>Prosqualodon</i>) -- whale-like skull with <b>dorsal</b>
nostrils (blowhole), still with un-whale-like teeth.
<li>
<i>Kentriodon</i>, an early toothed whale with whale-like teeth.
<li>
<i>Mesocetus</i>, an early whalebone whale
<li>
[note: very rarely a modern whale is found with tiny hind legs, showing
that some whales still retain the genes for making hind legs.]
</ul>
Transitional fossils from early eutherian mammals to the carnivores:
<ul>
<li>
Miacids (e.g. <i>Viverravus</i> and <i>Miacis</i>) -- small weasel-like animals
with very carnivore-like teeth, esp. the carnassial teeth.
<li>
Arctoids (e.g. <i>Cynodictis</i>, <i>Hesperocyon</i>) -- intermediate between
miacids and dogs. Limbs have elongated, carnassials are more
specialized, braincase is larger.
<li>
<i>Cynodesmus</i>, <i>Tomarctus</i> -- transitional fossils between arctoids
and the modern dog genus <i>Canis</i>.
<li>
<i>Hemicyon</i>, <i>Ursavus</i> -- heavy doglike fossils between the arctoids
and the bears.
<li>
<i>Indarctos</i> -- early bear. Carnassial teeth have no shearing action,
molars are square, short tail, heavy limbs. Transitional to the
modern genus <i>Ursus</i>.
<li>
<i>Phlaocyon</i> -- a climbing carnivore with non-shearing carnassials,
transitional from the arctoids to the procyonids (raccoons et al.)
</ul>
Meanwhile back at the ranch,<br>
<ul>
<li>
<i>Plesictis</i>, transitional between miacids (see above) and mustelids
(weasels et al.)
<li>
<i>Stenoplesictis</i> and <i>Palaeoprionodon</i>, early civets related to the
miacids (see above)
<li>
<i>Tunguricits</i>, transitional between early civets and modern civets
<li>
<i>Ictitherium</i>, transitional between early civets to hyenas
<li>
<i>Proailurus</i>, transitional from early civets to early cats
<li>
<i>Dinictis</i>, transitional from early cats to modern "feline" cats
<li>
<i>Hoplophoneus</i>, transitional from early cats to "saber-tooth" cats
</ul>
Transitional fossils from early eutherians to hoofed animals:
<ul>
<li>
Arctocyonid condylarths -- insectivore-like small mammals with classic
mammalian teeth and clawed feet.
<li>
Mesonychid condylarths -- similar to the arctocyonids, but with blunt
crushing-type cheek teeth, and flattened nails instead of claws.
<li>
Late condylarths, e.g. <i>Phenocodus</i> -- a fair-sized animal with
hoofs on each toe (all toes were present), a continuous series of
crushing-type cheek teeth with herbivore-type cusps, and no collarbone
(like modern hoofed animals).
<li>
Transitional fossils from early hoofed animals to perissodactyls:
<li>
[Perissodactyls are animals with an <b>odd</b> number of toes; most of the
weight is borne by the central 3rd toe. Horses, rhinos, tapirs.]
<li>
<i>Tetraclaeonodon</i> -- a Paleocene condylarth showing perissodactyl-like
teeth
<li>
<i>Hyracotherium</i> -- the famous "dawn horse", an early perissodactyl, with
more elongated digits and interlocking ankle bones, and slightly
different tooth cusps, compared to to <i>Tetraclaeonodon</i>. A small, doggish
animal with an arched back, short neck, and short snout; had 4 toes
in front and 3 behind. Omnivore teeth.
<li>
[The rest of horse evolution will be covered in an upcoming "horse
fossils" post in a few weeks. To whet your appetite:]
<li>
<i>Orohippus</i> -- small, 4/3 toed, developing browser tooth crests
<li>
<i>Epihippus</i> -- small, 4/3 toed, good tooth crests, browser
<li>
<i>Epihippus (Duchesnehippus)</i> -- a subgenus with <i>Mesohippus</i>-like teeth
<li>
<i>Mesohippus</i> -- 3 toed on all feet, browser, slightly larger
<li>
<i>Miohippus</i> -- 3 toed browser, slightly larger [gave rise to lots of
successful three-toed browsers]
<li>
<i>Parahippus</i> -- 3 toed browser/grazer, developing "spring foot"
<li>
<i>'Parahippus' leonensis</i> -- a <i>Merychippus</i>-like species of <i>Parahippus</i>
<li>
<i>'Merychippus' gunteri</i> -- a <i>Parahippus</i>-like species of <i>Merychippus</i>
<li>
<i>'Merychippus' primus</i> -- a more typical <i>Merychippus</i>, but still very
like <i>Parahippus</i>.
<li>
<i>Merychippus</i> -- 3 toed grazer, spring-footed, size of small pony
(gave rise to tons of successful three-toed grazers)
<li>
<i>Merychippus (Protohippus)</i> -- a subgenus of <i>Merychippus</i> developing
<i>Pliohippus</i>-like teeth.
<li>
<i>Pliohippus</i> & <i>Dinohippus</i> -- <b>one</b>-toed grazers, spring-footed
<li>
<i>Equus (Plesippus)</i> -- like modern equines but teeth slightly simpler.
<li>
<i>Equus (Hippotigris)</i>, the modern 1-toed spring-footed grazing zebras.
<li>
<i>Equus (Equus)</i>, the modern 1-toed spring-footed grazing horses & donkeys.
[note: very rarely a horse is born with small visible side toes, indicating
that some horses retain the genes for side toes.]
<li>
Hyrachyids -- transitional from perissodactyl-like condylarths to tapirs
<li>
Heptodonts, e.g. <i>Lophiodont</i> -- a small horse-like tapir, transitional
to modern tapirs
<li>
<i>Protapirus</i> -- a probable descendent of <i>Lophiodont</i>, much like modern
tapirs but without the flexible snout.
<li>
<i>Miotapirus</i> -- an almost-modern tapir with a flexible snout, transitional
between <i>Protapirus</i> and the modern <i>Tapirus</i>.
<li>
Hyracodonts -- early "running rhinoceroses", transitional to modern rhinos
<li>
<i>Caenopus</i>, a large, hornless, generalized rhino transitional between the
hyracodonts and the various later groups of modern & extinct rhinos.
<li>
Transitional fossils from early hoofed animals to some of the artiodactyls
(cloven-hoofed animals):
<li>
Dichobunoids, e.g. <i>Diacodexis</i>, transitional between condylarths
and all the artiodactyls (cloven-hoofed animals). Very condylarth-like
but with a notably artiodactyl-like ankle.
<li>
<i>Propalaeochoerus</i>, an early pig, transitional between <i>Diacodexis</i> and
modern pigs.
<li>
<i>Protylopus</i>, a small, short-necked, four-toed animal, transitional between
dichobunoids and early camels. From here the camel lineage goes through
<i>Protomeryx</i>, <i>Procamelus</i>, <i>Pleauchenia</i>, <i>Lama</i> (which are still alive;
these are the llamas) and finally <i>Camelus</i>, the modern camels.
<li>
<i>Archeomeryx</i>, a rabbit-sized, four-toed animal, transitional between the
dichobunoids and the early deer. From here the deer lineage goes through
<i>Eumeryx</i>, <i>Paleomeryx</i> and <i>Blastomeryx</i>, <i>Dicrocerus</i> (with antlers) and
then a shmoo of successful groups that survive today as modern deer --
muntjacs, cervines, white-tail relatives, moose, reindeer, etc., etc.
<li>
<i>Palaeotragus</i>, transitional between early artiodactyls and the okapi &
giraffe. Actually the okapi hasn't changed much since <i>Palaeotragus</i> and
is essentially a living Miocene giraffe. After <i>Palaeotragus</i> came
<i>Giraffa</i>, with elongated legs & neck, and <i>Sivatherium</i>, large ox-like
giraffes that <b>almost</b> survived to the present.
</ul>
</ul>
So, there's a <b>partial</b> list of transitional fossils.
<p>
This really only scratches the surface since I left out all groups
that have no surviving relatives, didn't discuss modern amphibians or
reptiles, left out most of the birds, ignored the diversity in modern
fish, didn't discuss the bovids or elephants or rodents or many other
mammal groups.... I hope this gives a taste of the richness of the
fossil record and the abundance of transitional fossils between major
vertebrate taxa.
<p>
By the way, notice that this list mostly includes transitional fossils
that happened to lead to modern, familiar animals. This may
unintentionally give the impression that fossil lineages proceed in a
"straight line" from one fossil to the next. That's not so; generally
at any one time there are a whole raft of successful species, only a
few of which happened to leave modern descendents. The horse family is
a good example; <i>Merychippus</i> gave rise to something like 19 new
three-toed grazing horse species, which traveled all over the Old and
New Worlds and were very successful at the time. Only one of these
lines happened to lead to <i>Equus</i>, though, so that's the only line I
talked about. Evolution is not a ladder, it's a branching bush.<p>
They merely rearrange the traits that already exist in a species, sometimes repeating, sometimes deleting what is already there.
There is once again no basis to this argument. Mutations can add a genetic sequence which doesn't already exist.
As expected…most mutations are either lethal or harmful to the organism experiencing them.
No they aren't. Chances are that you have mutated genes in your body. They just won't get passed on unless they are in your reproductive organs.
an eye or wing coming into being) has ever been found in either living or fossil specimens.
I'll repeat the fossil names from the info above:
Lisboasaurus estesi and other "troodontid dinosaur-birds"
Protoavis
Archeopteryx
"Chinese bird"
"Las Hoyas bird"
Toothed Cretaceous birds, e.g. Hesperornis and Ichthyornis.
Natural selection is a conservation mechanism, not one of innovation as required by evolution. Evolution requires new traits. Natural selection does not provide any; it merely selects what is already present.
True, natural selection only limits the choice, but mutations can increase the choice.
