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.

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.

The occurrence of these left over parts also extends to dolphins that very rarely will actually have external “legs.”

The limbs are also visible en utero.

Hair is another sign of cetacean land origins.

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

Manatee fingernails and hair

Recurrent Laryngeal Nerve

Amphiumas’ vestigial legs

Salamanders evolving towards leglessness

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.

A few other resources on leglessness: http://life.bio.sunysb.edu/ee/wienslab/wienspdfs/2009/Evolution_of_Limblessness.pdf http://whitelab.biology.dal.ca/lb/Bejder%20and%20Hall.pdf http://etb-visual-evolution.blogspot.com/2012/05/snakes-with-legs-snake-evolution.html http://www.flickr.com/photos/stephenmahony/8530271046/ http://www.flickriver.com/photos/tags/wormskink/interesting/ http://gretelinaustralia.wordpress.com/2012/03/07/reptilien/ Dinosaur Arms – a similar series of changes took place with certain dinosaurs that no longer had much need for arms or fingers.

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.

Flightless Cormorant 

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.

Read more: http://ncse.com/rncse/30/4/vestigial-structures-exist-even-within-creationist-paradigm The horse vestigial bone structures don’t end there.  The ulna and fibula also show signs of being remnants of past forms.

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.

Subterranean or fossorial eyes similarly show us the vestigiality. (Numerous examples could be listed here.

 Pinniped Ears 

Pinniped nails

Koala Skulls

Stapedial Artery

Blind Spot

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/

Ear image from:
http://elementsofmorphology.nih.gov/index.cgi?tid=792cfeacf93ca391

Picture that is frighteningly enlarged of a preauricular pit (beware):
http://pinna.hawkelibrary.com/pitsandsinuses/1_19?full=1

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/

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/

More on human pseudogenes:

http://www.talkorigins.org/faqs/comdesc/section2.html#mol_vestiges
http://en.wikipedia.org/wiki/Human_disabled_pseudogenes_list
http://www.uam.es/personal_pdi/ciencias/genhum/bibliogenoma/pseudogenes2004.pdf
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC403797/
http://www.pseudogene.org/human/index.php