Lesson plans, evidence examples, images, powerpoint presentations, all made available for free.
Remnants
In the United States, we put marks on our coins to show where they were produced. If the letter ‘D’ is on the bottom right side of the heads side then it was made in Denver, Colorado. Likewise, ‘P’ stands for Philadelphia (sometimes no mint mark), ‘S’ for San Francisco, ‘W’ for West Point, etc.
Similarly to how we can look at this coin and know where it came from we can look at species today and find signs of the past generations which they came from.
Claim: Descent with modification–species have changed over generations.
Predictions: We would find signs of past generations, remnants of where species came from. These remnants might come in the form of repurposed traits, maladative traits, non-adaptive traits, or the lack of sensible traits.
Falsification: Species are completely unique and unlike other species. They are perfectly adapted to their environment.
Observations: Vestigial Structures, pseudogenes, atavistisms (see examples below).
Corroboration: The vestigial structure is found to be homologous to another species structure. The trait is found to be injurious or does not give an adaptive advantage.
Inference: Species only have what mutation and past generations gave them. Repurposed, maladaptive traits, nonadaptive traits, and missing reasonable traits are all signs of species natural origin.
Vestigial Structures
If evolution is true, we should be able to find leftovers from past generations with species–anatomy or genes that tell of where they came from. How would we show that they are vestigial as opposed to adaptations? Well, we’d need to show that they have little or no connection to their original adaptive purpose or in some cases even hurt the species’ survival and reproduction capabilities. Also important here is how homologous they are to other species. While often exhibiting awe-inspiring adaptations, species are flawed and imperfect. Species only have what past generations gave them.
Locomotion transitions: Some of the best examples of vestigial structures come from species that have made a transition from locomotion on land, water, or air to a different medium (for instance whales from land to sea, birds from land to air, legless lizards from land to subteranean, etc.). Being conscious of this pattern can allow you to find your own examples of remnants! Please comment them at the bottom of this page!
Whales
Below is a fetal fin whale showing the vestigial tooth buds within their jaw.
http://whyevolutionistrue.wordpress.com/2010/07/22/baleen-whales-a-lovely-transitional-form/demere-tooth-buds_2_2/ Original paper: http://www.sdnhm.org/archive/research/paleontology/DemereMorphoBaleenTeeth.pdf
While whales don’t typically have external legs (though whaling tales do exist) they do have the remnants of internal ones and the pelvises that supported them.
***See these fossils from different angles: http://bergenmuseum.uib.no/fagsider/osteologi/hvaler/e_utstillingen_bekken.htm http://bergenmuseum.uib.no/fagsider/osteologi/hvaler/e_utstillingen_bekken.htmhttp://bergenmuseum.uib.no/fagsider/osteologi/hvaler/e_skjelett.htmNorth Atlantic right whale http://www.whoi.edu/science/B/whalepelvics/cgi-bin/page.cgi?t=Eubalaena_glacialis Amazing complete list: http://www.whoi.edu/science/B/whalepelvics/cgi-bin/page.cgiBowhead whale – look at that little leg! http://www.whoi.edu/science/B/whalepelvics/cgi-bin/page.cgi?t=Balaena_mysticetusThis photo is of an atavistic set of humpback whale legs. (Atavistic means that the previously dormant genes for legs in whales were mutated and turned back on to result in a whale with vestigial legs.) http://www.talkorigins.org/faqs/comdesc/section2.html http://digitallibrary.amnh.org/dspace/handle/2246/4849
The occurrence of these left over parts also extends to dolphins that very rarely will actually have external “legs.”
Excellent article on cetacean evolution: http://link.springer.com/article/10.1007%2Fs12052-009-0135-2/fulltext.htmlhttp://etb-whales.blogspot.com/2012/03/dolphin-hind-legs-hind-limb-bud-images.html
Hair is another sign of cetacean land origins.
http://nmmf.org/searching-for-dolphin-hair/ In some species of dolphin these hair follicles have evolved into electro receptors! http://blogs.discovermagazine.com/notrocketscience/2011/07/26/dolphin-detects-electric-fields-with-ex-whisker-pits/#.UkmuQdJwpft
http://www.dolphinleap.com/akebaby/Adult cetaceans have a single blow hole on the top of the head. Other mammals and embryonic cetaceans have their nostrils on the front of their head. Yet another remnant of their shared ancestor.http://www.bio.georgiasouthern.edu/bio-home/harvey/lect/lectures.html?flnm=evel&ttl=Evolution&ccode=el&mda=scrn
If you didn’t know any better, you might think this was a flattened elephant foot. Well, that’s not far from the truth since manatees are closely related to elephants. West Indian Manatee (Trichechus manatus) has fingernails on their flippers and hair on their body (visible in this photo).http://theobligatescientist.blogspot.com/2010/05/monday-mammal-3-west-indian-manatee.html Also: http://etb-whales.blogspot.com/2012/03/sea-cows-manatee-and-sirenia-evolution.html http://insearchofmamiwata.blogspot.com/2012/05/manatee-rescue-at-lac-de-guiers.html
Recurrent Laryngeal Nerve
There is a nerve homologous in fish (our ancestors) and in modern tetrapods (like us) called the recurrent laryngeal nerve. It’s called ‘recurrent’ because to serve its function of helping speak and swallow it travels from the top of the vagus nerve down around the aorta back to the larynx. This trip takes the nerve unnecessarily several inches out of the way. Why? Because the set up of vagus nerve, aorta, larynx area, made great sense when our ancestors were fish and things were organized different. Now we have the same arrangement because of our evolutionary history rather than its optimal function. http://techcrash.net/giant-neurons/The recurrent laryngeal nerve (see description above) takes on comical proportions in the giraffe as it travels a total of 4.5 meters (15 feet) out of the way. http://blog.eternalvigilance.me/2013/04/evidence-for-evolutionism-1-the-recurrent-laryngeal-nerve/
Amphiumas’ vestigial legs
Amphiuma means http://en.wikipedia.org/wiki/Two-toed_amphiumaAmphiuma tridactylum http://www.caudata.org/cc/species/Amphiuma/Amphiuma.shtml
Salamanders evolving towards leglessness
Batrachoseps attenuatus – the legs are still there but who knows for how long. By squamatologist http://www.flickr.com/photos/squamatologist/5452483498/ Also: http://whyevolutionistrue.wordpress.com/2012/09/24/another-creationist-drops-by-to-show-that-theres-no-evidence-for-evolution/ http://www.flickr.com/photos/tigerhawkvok/3257151878/ http://alhlabbench.wordpress.com/tag/force-enhancement/
Some snakes also have the remnants of legs and pelvises that are used by males to help grip females during mating.
Legless lizards are another example of leftover limbs.
common scaly-foot (Pygopus lepidopodus) http://goulburnbrokendelmaimpar.wordpress.com/similar-species/other-legless-lizards/ Also, http://www.arkive.org/western-hooded-scaly-foot/pygopus-nigriceps/image-G139321.htmlPygopodus lepidopodus http://scienceblogs.com/tetrapodzoology/2011/06/03/hello-pygopodids/
Large-scaled grass lizard, Chamaesaura macrolepis macrolepis http://www.markoshea.info/oba4-2_s.africa03-1a.phpSkink feet appear at every point in the progression from fully five toed foot to vestigial limb bud. Read more: http://www.environment.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume2a/31-fauna-2a-squamata-scincidae.pdfLegless Bachia lizard. http://news.mongabay.com/2008/0429-cerrado.htmlSilvery Dwarf Burrowing Skink (Scelotes bipes) http://www.buckhambirding.co.za/wp/?page_id=7654
Hesperornis regalis – this aquatic bird/dinosaur barely has wings. http://www.geol.umd.edu/~jmerck/nature/specimens/htmls/hesperornis70177.html Read more here: www.google.com/url?q=http%3A%2F%2Fwww.geo.utexas.edu%2Fcourses%2F302d%2FMistaken%2520Extinction%2FChapter%252014.pdf&sa=D&sntz=1&usg=AFQjCNG8J_fA4AusBDhdUahLTLO_f9sjQAhttp://qilong.deviantart.com/art/Not-a-Bird-109530255http://blogs.smithsonianmag.com/dinosaur/2011/01/linhenykus-a-weird-one-fingered-dinosaur/
Bird fingers – the above examples aren’t the only dinosaurs with intermediate fingers. There are quite a few examples of birds (which are a subset of dinosaurs) alive today that have something like fingers.
Ostriches have claws. http://www.flickr.com/photos/davidbygott/4435592628/Ostrich http://en.wikipedia.org/wiki/OstrichEmu wing claw. http://blog.revealedsingularity.net/category/tuesday-tetrapod/page/2
Emu wing and claw. http://scienceblogs.com/tetrapodzoology/2009/04/27/dissecting-an-emu/ Also: http://aaaamory.deviantart.com/art/Emu-Wing-Claw-135132877 http://www.backyardchickens.com/t/768667/photo-gallery
Southern Screamer (Chauna torquata) wing claw. http://www.theguardian.com/science/punctuated-equilibrium/2010/sep/28/1Finger and claws of the Crested Screamer (Chauna torquata). http://whatsinjohnsfreezer.com/2013/05/ Also: http://scienceblogs.com/tetrapodzoology/2010/06/20/detachable-wing-daggers/Kiwis also have a single claw on their wings. http://www.kiwisforkiwi.org/about-kiwi/kiwi-facts-characteristics/flightless/
Hoatzin also have claws and digits.
Baby hoatzin with wing claws visible. http://www.natgeocreative.com/photography/1071618 Also: http://www.superstock.com/stock-photos-images/4201-39855 http://biologicalbeachcombing.blogspot.com/2012_02_01_archive.html
Flightless Cormorant
Galapagos Flightless CormorantThis wing looks awful because it’s evolutionarily inbetween being used for flight (which it can no longer do) and being fully adapted for underwater life (where it hunts for fish). http://www.treknature.com/gallery/South_America/Ecuador/photo146764.htm http://www.naturediscoveries.com/galapago/galapago.htm
Horses – The evolution of horse appendages is well documented within the fossil record. Please see here for more illustrations on this. This change, however, is still in process and has left a number of remnants that teach us about the horse’s ancestral past.
The most relevant evolutionary leftover for horse racing is the splint bone. They reside on either side of the third metacarpal bone and are often injured in racing causing great discomfort. These splint bones are the remnants of ancient fingers. They are now treated with extensive wrapping before racing. http://en.wikipedia.org/wiki/Limbs_of_the_horsehttp://www.studyblue.com/notes/note/n/the-rest-of-ch-6-skeletal-system/deck/5392839
The purpose of these familiar wraps is to protect the vestigial fingers on either side of the horse’s third metacarpal bone which can be painfully broken during races. http://en.wikipedia.org/wiki/Limbs_of_the_horseThis is one example of an x-ray of a horse with a fractured vestigial splint bone, ruining its racing prospects. http://www.horsegroomingsupplies.com/horse-forums/fractured-splint-bone-462116.html
The ulna through the process of evolution has fused to the radius. The fuse site and structure are variable between individuals. http://www.horse360.com.au/app/images/Horse%20360%20Android%20Tablet/general/The ulna is visible on top of the radius. Notice the aperture between the two bones demonstrating partial fusing between the bones. http://www.onlineveterinaryanatomy.net/content/equine-radius-and-ulna-situ-lateral-view
The horse fibula is almost gone. One of the author’s of this site has done morphological studies on mice and knows this phenomena of vestigial fibulas to be widespread. http://www.horse360.com.au/app/images/Horse%20360%20Android%20Tablet/general/The vestigial fibula is visible at the top of the first bone from the bottom angled towards the right. http://en.wikipedia.org/wiki/Skeletal_system_of_the_horse4 on the right is the vestigial fibula of a cow. Again this pattern is widespread throughout various mammal clades.http://www.aps.uoguelph.ca/~swatland/ch2_1.htmVestigial Chicken FibulasVestigial fibulas are common among a number of species, one such is the chicken. If you’ve ever eaten a chicken drum stick you are likely familiar with the sliver of bone next to the tibia that doesn’t seem to do or connect to much. There’s a reason for that; it’s vestigial. Check back soon because we will shortly have a lesson plan on how to dissect a chicken and talk about its dinosaur remnant. Look under ‘Lesson Plans’ for more. http://kriegerscience.wordpress.com/2010/10/24/how-to-dissect-a-chicken-leg/
Blindness helps us see evolution A very long list of cave and subterranean species could be produced that demonstrate the reduction and mutation of eyes. For some species the eyes (but often not the sockets) are completely gone or so reduced that they are almost not visible.
Very interesting research has been (and is being) done on Mexican blind cave fish (Astyanax mexicanus). Depicted here on the left top is a blind cave fish. On the bottom right is a sighted and very close relative of the blind cave fish. On the right are pictures of two fish that had their lenses switched early in development. The top right is a sighted blind cave fish that had a lens implanted. The bottom is a sighted fish that had its lens removed and developed very similarly to the blind fish. http://jhered.oxfordjournals.org/content/96/3/185.full Does this pique your interest? Here are a few more interesting articles on the topic of these two closely related but different species:http://biologybizarre.blogspot.com/2013/04/eyeless-cavefish-are-pickin-up-good_25.html http://www.nature.com/news/2009/090408/full/458695a.html http://www.huffingtonpost.com/richard-borowsky/cave-fish-insomnia_b_1981606.html http://news.sciencemag.org/2004/10/cave-fish-go-blind-purpose
Subterranean or fossorial eyes similarly show us the vestigiality. (Numerous examples could be listed here.
The arrow points to a vestigial eye of a mole. http://naturalistguy.com/2011/06/24/3191/Interesting work has been done on the lens genes of moles. They are highly mutated but seem to still have some relevance since they are somewhat conserved when compared to other mammals. Read more on this: http://www.biomedcentral.com/1741-7007/6/44/abstract http://mbe.oxfordjournals.org/content/2/4/279.full.pdf http://www.pnas.org/content/84/15/5320.full.pdfAlso interesting: http://squamates.blogspot.com/2010/11/fossorial-eyes.html
Pinniped Ears
Vestigial ear of the Galapagos fur-seal. The ears of pinnipeds (seals, sea lions, and their relatives) are at various stages of becoming smaller and more streamlined. For many species they still linger and are a cute reminder of their evolutionary past. http://birdsasart.com/bn238.htmMore: http://www.columbiariversealions.com/2012/01/whats-the-difference-between-seals-and-sea-lions/ http://www.newtonsapple.org.uk/evolution-of-the-elephant-seal/ http://www.marinemammalcenter.org/education/marine-mammal-information/pinnipeds/guadalupe-fur-seal/ http://en.wikipedia.org/wiki/File:Walrus_-_Kamogawa_Seaworld_-_1.jpg
Pinniped nails
While their feet have been highly modified for their life in the sea, the still retain their ancestor’s nails, often on their front and hind limbs. These are visible as small indentations even in the highly modified hind limbs of the elephant seal. http://www.oceanlight.com/spotlight.php?img=02257 http://www.oceanlight.com/spotlight.php?img=03234 They aren’t totally functionless, though: http://www.flickr.com/photos/marlinharms/5737534193/ http://z-letter.com/2010/10/27/samc/ http://www.arkive.org/california-sea-lion/zalophus-californianus/image-G28770.html http://www.care2.com/c2c/groups/disc.html?gpp=11767&pst=1105790 http://www.arkive.org/northern-elephant-seal/mirounga-angustirostris/image-G27354.html
Koala Skulls
Koala brains take up roughly half of their brain case. Why? Because the diet they have recently evolved to eat–eucalyptus leaves–is very nutritionally poor and they need to conserve as much energy as possible. For them that means having a smaller brain. Why not also have a smaller brain case? Well, that’s evolutionarily more difficult to select for and evolution tends to take the path of least resistance. Image: http://www.pbs.org/wnet/nature/lessons/the-koala-diet/enhanced-video-resource/7852/ Read more: http://www.pbs.org/wnet/nature/lessons/the-koala-diet/enhanced-video-resource/7852/
Stapedial Artery
Early in development the stapedial artery goes right through our inner ear stapes bone. The position of this artery used to make sense when our ancestors used what is now the stapes bone as part of their jaw. http://www.ajnr.org/content/21/3/572/F6.expansion.htmlOur throat design is a major choking hazard. Why is it that our esophagus is so close to our trachea? It’s just how evolution would it up to be. It could be that we would eat with one tube and breathe/speak with another. But it’s not. Evolution only builds on what it has been given. http://thebrain.mcgill.ca/flash/capsules/outil_bleu21.html
Blind Spot
The blind spot is an area that the optic nerve emerges from and goes /over/ the retina rendering that area blind. This is widely considered a very poor design, since it is far from necessary (other clades like cephalopods have their nerves going behind the retina, a more functional design). http://www.studyblue.com/notes/note/n/vision-the-eye-/deck/712392Notice how the nerve “wiring” goes over the photoreceptors, reducing their effectiveness. http://ceph.wikispaces.com/
Want to see evolution? Just close one eye. The blind spot is an area of our retina that is unable to see because the optic nerve and associated vasculature emerge through the retina and go /over/ it. This is a terrible way to design an eye and shows us the haphazard design that evolution can take. http://histology.med.umich.edu/medical/eye The light spot is your blind spot here: http://thebrain.mcgill.ca/flash/capsules/outil_bleu21.html
The maxillary sinus is the site of most sinus infections in humans. Why? Because it drains up. This worked well when our ancestors were quadrupedal and they had more opportunities for drainage. For today’s humans they drain poorly and are traps for bacteria to grow causing sinus infections.http://mysinusinfectionsymptoms.com/paranasal-sinuses/maxillary-sinuses/#!prettyPhoto Also: http://www.ncbi.nlm.nih.gov/pubmed/12793110 http://www.ncbi.nlm.nih.gov/pubmed/21303605
Wisdom teeth aren’t so wise. Our jaws and skulls have evolved to be smaller but our teeth, which are controlled by a different set of genes are slow to catch up.http://www.drshenfield.com/WisdomTeeth.htmlCan you or anyone you know wiggle their ears? If so, you’re using vestigial muscles that once directed our ears to point in the direction of a sound. http://thesymbiont.blogspot.com/2010/06/human-evolution-proofs-in-picture-form.htmlThe writer for this portion of EvolutionEvidence.org spent 8 days in the hosptal and almost died after his gangrenous appendix ruptured. The appendix serves some function in humans and other species by acting as a bacteria reservoir. That said, its original purpose was to break down cellulose. http://science.howstuffworks.com/life/human-biology/appendix.htm
The morphology of several species of mammal. Larger caecums and appendixes function to digest cellulose, a particularly difficult polymer to break apart. http://www.talkorigins.org/faqs/vestiges/appendix.htmlTucked in the eye of each human is the remnant of a nictitating eyelid that could be used to protect the eye, typically during feeding. http://www.bio.miami.edu/dana/160/160S13_5.htmlHave you ever stopped to think about why humans have canines? Evolution! They are the remnants of predatory and display fangs.http://www.fossilized.org/anthro_textbook/index.php?subtopic=Dental%20Pattern&week=4&topic=Primate%20Features%20of%20Humans&topic_subdb=Primate%20Features%20of%20Humans&subfield=Human%20as%20Primates%20and%20Modern%20Human%20AdaptationsOnce used to trap warm air to aid insulation when our ancestors had denser hair and to cause hair to rise to increase the apparent size of our ancestors during confrontations, goosebumps are now vestigial. http://www.telegraph.co.uk/science/science-news/9738570/Goosebumps-the-lie-detector-for-emotions.htmlYou Hiccup Because of EvolutionWhy do we hiccup? Evolution. Our amphibian ancestors needed to be able to switch back and forth between breathing air with lungs and pushing water over their gills. The nerve signals from the irritation of the phrenic nerve that regulates this process of snapping the epiglottis shut and sucking in water is identical to a hiccup. We still have the ability but no longer have the gills to make it worth anything. Bonus fact: Charles Osborne holds the Guinness World Record for the longest continuous hiccup at 68 years. http://en.wikipedia.org/wiki/Charles_Osborne_(hiccups) Read more on our evolutionary vestiges: http://mukto-mona.net/Special_Event_/Darwin_day/2009/english/SA_old_bodyShubin.pdfhttp://www.nature.com/scientificamerican/journal/v300/n1/box/scientificamerican0109-64_BX2.html http://health.howstuffworks.com/diseases-conditions/respiratory/hiccup1.htm http://www.bbc.co.uk/news/health-13278255These are the pharyngeal gills or arches of a human early in development. http://php.med.unsw.edu.au/embryology/index.php?title=Pharyngeal_archesHere are pharyngeal gill arches in a skate fish that are homologous to humans. http://www.pnas.org/content/106/14/5720.full.pdf
Common Pit Near Ear from Fishy BeginningsDo you have or know anyone that does have a pit/sinus/cyst near the top of their ear by their face? If so, you/they are demonstrating a common and slight malformation of one of the branchial arches, aka ancient gills!
Early in development humans (as well as birds, reptiles, amphibians, and, of course, fish) all have these gill like arches. In our ancestors, they developed into gill arches. In us, some of these gills develop into parts of our jaw, inner ear, and throat, such as the hyoid bone (The free floating bone directly above the “Adam’s apple” on our neck. Go ahead, feel for it now.).
Sometimes that process of turning former gills into a throat leaves behind little leftovers of our evolutionary past. One such example is the preauricular (before the ear) pit, which in essence is a tiny gill slit. Isn’t that amazing! Check it out and share with others! They deserve to know about the incredible history their body is demonstrating!
You need to watch “Your Inner Fish” by Neil Shubin (or better yet, buy the book!): http://www.pbs.org/your-inner-fish/watch/
Read more (and source of embryo pic): http://scienceblogs.com/pharyngula/2006/06/21/deep-homologies-in-the-pharyng/
Picture that is frighteningly enlarged of a preauricular pit (beware): http://pinna.hawkelibrary.com/pitsandsinuses/1_19?full=1
The philtrum, or ridge above your lip is where during development the two sides of your face seal together. Why create a face this way, especially when it is so prone to error resulting in cleft palates in 1/700 babies? It’s yet another compromise evolution has made as it made a fish into a human.Watch an animation of this developmental process as the nostrils move from the top of our head (formerly the front, on a fish): http://www.bbc.co.uk/news/health-13278255http://whyevolutionistrue.wordpress.com/2011/05/06/our-inner-fishes/The testicles of our ancestors were inside their body. As mammals became warm blooded, it became advantageous to move the testicles outside the body to function at their cooler, optimum temperature. This process of developing the testicles inside (as our ancestors did) and then moving them outside the body is fraught with disadvantages including hernias and undescended testicles. http://mukto-mona.net/Special_Event_/Darwin_day/2009/english/SA_old_bodyShubin.pdf http://www.nature.com/scientificamerican/journal/v300/n1/box/scientificamerican0109-64_BX1.html http://www.drugs.com/cg/inguinal-hernia.htmlThe path of the vas deferens is another example of a design flaw in human development and morphology due to its evolutionary past when testicles resided inside the body of our cold blooded ancestors. http://commons.wikimedia.org/wiki/File:Route_of_vas_deferens_en.svg
Humans have tails as embryos. This tail later moves into the body but still retains much of its bone structure in the coccyx.Our eyes remain on the sides of our head during development, much the same as they were in the adult form of our fish ancestors. http://en.wikipedia.org/wiki/Embryo
Vestigial tail that now has auxiliary function in muscle attachment.Why do male mammals have nipples? Evolution. Males and females share much of the same developmental template started long ago. http://www.museumsinflorence.com/uffizi/Pal/palazzo.htmlThe clitoris and penis also share developmental origins. This is equally true for the Grafenburg spot and the prostate. http://thesymbiont.blogspot.com/2010/06/human-evolution-proofs-in-picture-form.html
Have you ever considered why the hair on your body faces in the direction that it does? When our ancestors walked on all four legs all the hair faced down and allowed rain to drip off quickly.http://thesymbiont.blogspot.com/2010/06/human-evolution-proofs-in-picture-form.htmlOur sweat glands are optimally placed to cool our body when we were quadrupeds, walking on all four legs. http://thesymbiont.blogspot.com/2010/06/human-evolution-proofs-in-picture-form.htmlhttp://io9.com/5984591/you-probably-dont-know-how-many-holes-are-in-your-body-right-now
Human babies are born with a vestigial coat of hair called ‘lanugo.’http://www.babyfaq.info/skin/lanugo.phpThe baby grasping reflex in humans is a vestigial trait that allowed babies to hold on to the hair of their mother and prevent being dropped. http://science-at-home.org/palmar-power-precision-and-prints-hands-and-fingers-for-all-ages/Human embryos have a yolk sac early in development. http://discoveringsomethingneweveryday.blogspot.com/2012/11/human-embryo-at-6-weeks-only-half-inch.htmlhttp://biologicalfreak0729.blogspot.com/2012_10_01_archive.html
Many mammal species have vomeronasal or Jacobson’s organs to sense pheromones, or scents associated with reproductive fertility. Humans have the vestigial remains of the organ in their nasal passageway but no known ability to sense pheromones. http://rhinitis.hawkelibrary.com/album05/33_G?full=1http://www.entusa.com/nose_photos.htmhttp://en.wikipedia.org/wiki/File:Gray51.pnghttp://www.scielo.cl/scielo.php?pid=S0717-95022008000200006&script=sci_arttexthttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC1468331/
In different surveys 7-20% of people don’t have this vestigial muscle. Formerly used for grasping with the foot the plantaris tendon now serves possible non-essential functions such as proprioception, or the perception of joint placement in space. In surgeries that require the replacement of tendon, the plantaris is one of the first tendons to be removed and used elsewhere.http://en.wikipedia.org/wiki/Plantaris_musclehttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC1978447/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1978447/The placement and structure of the shoulder and scapula in humans reveals that our arboreal past. The placement of the scapulas dorsally on our back and the side facing shoulder point are ideal for hanging and pulling.http://www.antiquityofman.com/ape-human.htmlhttp://openi.nlm.nih.gov/detailedresult.php?img=2860095_10764_2010_9399_Fig6_HTML&req=4
10% of humans have “Darwin’s tubercle” a feature that formerly aided our ancestors in directing sound into their ear. The image depicts a human, a macaque, and an illustration from Darwin’s “Descent of Man.” http://othersidereflections.blogspot.com/2011/03/weit-human-vestigiality-atavisms.htmlhttp://en.wikipedia.org/wiki/Darwin’s_tubercleWhy do humans shed teeth in adolescence? Our ancestors, such as reptiles and fish, shed teeth throughout their life (one of the reason fossil shark and alligator teeth are common in some regions). Today while this trait of shedding teeth unnecessarily is metabolically taxing and unnecessary we continue to because of the genetic programming we received from our teeth shedding ancestors. http://thesymbiont.blogspot.com/2011/01/teeth-why-we-lose-em-and-how-other.html http://todayilearned.co.uk/2011/06/20/childs-skull-with-adult-teeth-preparing-to-change-the-baby-ones/ http://forum.santabanta.com/showthread.htm?324800-Facts-About-Human-Body/page2
Sometimes the most puzzling vestigial structures are the most obvious. Why do we have toe nails? To prevent stubbing? Then why aren’t they on the front of our toes? Formerly they were advantageous for gripping and digging. Now they remain as remnants. http://thesymbiont.blogspot.com/2010/06/human-evolution-proofs-in-picture-form.html
Genetic Remnants, aka Atavisms (see whales at top of page, as well) –
60 to 80 million years ago the ancestors of birds had teeth. Above is a diagram showing that mutant chickens can revive some of the teeth genes to begin the growth of teeth. On the far left is the gene ‘Shh’ (involved in tooth growth) being expressed in an crocodile. The middle picture is the same gene being expressed in a chicken mutant. The right picture is a normal chicken. http://www.nature.com/scitable/topicpage/atavism-embryology-development-and-evolution-843There is an interesting group of scientists that are trying to reverse engineer a dinosaur from the remnant psuedogenes within a chicken. Check out more on this: http://apt46.net/2011/09/28/reverse-engineering-a-dinosaur/
The internet is full of pictures of people with atavistic tails; here’s just one. The vertebrae labeled in yellow are abnormal and were removed by surgery. They represent the revival of ancient tail genes. http://www.talkorigins.org/faqs/comdesc/section2.html#atavisms
Pseudogenes
Humans could smell many, many times better than we do…If our genes hadn’t mutated. More than 51% of human olfactory genes have become mutated and turned off. Why? There wasn’t the necessary selective pressure to keep them intact. One interesting reason is that we, unlike many other simians, have trichromacy, or three color receptors (red, green, blue) rather than two, like many other simians. This heightened visual acuity to distinguish ripe from unripe, rotten from fresh likely made accute smell unnecessary.http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0020005http://www.nikon.com/about/feelnikon/light/chap05/sec01.htmThis same trend is present in aquatic mammals, like sea lions, whales, and dolphins. Dolphins have 80% of their olfactory (smell) genes mutated into pseudogenes. The same is also true of sea snakes.http://whyevolutionistrue.wordpress.com/2009/12/21/more-evidence-for-evolution-dead-genes-in-sea-snakes/
Other mammals can produce vitamin C. They don’t need it from their diet. Humans, on the other hand, have had ancestors that have been eating fruit for so long (which is high in vitamin C) that our vitamin C genes is long ago mutated. We do, however, still possess its remnant in pseudogene form. http://evolutionaos.wikispaces.com/5a.+Conservation+of+Genes
Vitellogenin is a protein found in egg yolks and helps nourish growing embryos. The gene for this protein has been identified and sequenced. The odd thing is that placental (that’s us!) and marsupial mammals have the gene, but it’s a pseudogene since we no longer need it due to lactation and/or placentas. News article: http://www.sciencedaily.com/releases/2008/03/080318094610.htm Journal article: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0060063 Image: http://commons.wikimedia.org/wiki/File:Yolk.jpg
Humans have 23 pairs of chromosomes. Chimpanzees have 24. If we’re so closely related and share roughly 98% of our genes, how could this be? Chromosome fusion! Human chromosome 2 shows signs of a fusion event. Within this chromosome are extra telomeres (repeat sequences at the tips of chromosomes), and centromeres (sequences that are at the center of chromosomes and aid in division). These anomolies and leftovers from our ancestor’s chromosome formation are excellent evidence in support of evolution.http://blogs.discovermagazine.com/loom/2012/07/19/the-mystery-of-the-missing-chromosome-with-a-special-guest-appearance-from-facebook-creationists/#.UnO7VHBwpKU‘H’ stands for human and ‘C’ stands for chimpanzee. Depicted here is the large scale similarities between human and chimpanzee chromosomes. Not only do we share 98% of our genes with chimps, but they are arranged and organized on chromosomes in incredibly similar fashions. Notice the chromosome fusion in chromosome 2, mentioned above. http://science.kqed.org/quest/2008/05/12/chromosome-fusion-chance-or-design/
