More interesting evidence confirming that some do get a little tail.
talkorigins.org
"Primarily due to intense medical interest, humans are one of the best characterized species and many developmental anomalies are known. There are several human atavisms that reflect our common genetic heritage with other mammals. One of the most striking is the existence of the rare "true human tail" (also variously known as "coccygeal process," "coccygeal projection," "caudal appendage," and "vestigial tail"). More than 100 cases of human tails have been reported in the medical literature (Matsuo et al. 1993). Less than one third of the well-documented cases are what are medically known as "pseudo-tails" (Dubrow et al. 1988). Pseudo-tails are not true tails; they are simply lesions of various types coincidentally found in the caudal region of newborns, often associated with the spinal column, coccyx, and various malformations. In contrast, the true atavistic tail of humans develops from the most distal end of the embryonic tail found in the developing human fetus (Belzberg et al. 1991; Dao and Netsky 1984), and it is usually benign in nature (Dubrow et al. 1988; Spiegelmann et al. 1985). The true human tail is characterized by a complex arrangement of adipose and connective tissue, central bundles of longitudinally arranged striated muscle in the core, blood vessels, nerve fibres, nerve ganglion cells, and specialized pressure sensing nerve organs (Vater-Pacini corpuscles). It is covered by normal skin, replete with hair follicles, sweat glands, and sebaceous glands (Dao and Netsky 1984; Dubrow et al. 1988; Spiegelmann et al. 1985). True human tails range in length from about one inch to over 5 inches long (on a newborn baby), and they can move and contract (Dao and Netsky 1984; Lundberg et al. 1962). Although they usually lack skeletal structures, they have also been found with cartilage and multiple articulating vertebrae (Fara 1977; Matsuo et al. 1993). Caudal vertebrae are not a necessary component of mammalian tails; contrary to what is frequently reported in the medical literature, there is at least one known example of a primate tail which lacks vertebrae, as found in the rudimentary two-inch-long tail of Macaca sylvanus (the "Barbary ape") (Hill 1974, p. 616; Hooten 1947, p. 23). True human tails are rarely inherited, though familial cases are known (Dao and Netsky 1984; Standfast 1992). As with other atavistic structures, human tails are most likely the result of either a somatic or germline mutation that reactivates an underlying developmental pathway which has been retained in the human genome (Dao and Netsky 1984; Hall 1984; Hall 1995).
It should be noted here that the existence of true human tails is quite shocking for many religiously motivated anti-evolutionists, such as Duane Gish, who has written an often-quoted article entitled "Evolution and the human tail" (Gish 1983; see also Menton 1994). Solely based on the particulars of a single case study (Ledley 1982), Gish has erroneously concluded that atavistic human tails are "nothing more than anomalous malformations not traceable to any imaginary ancestral state." However, Gish's arguments are clearly directed against pseudo-tails, not true tails, since true human tails are complex structures which have muscle, blood vessels, occasional vertebrae and cartilage (Fara 1977; Matsuo et al. 1993), they can move and contract, and they are occasionally inherited (Dao and Netsky 1984; Standfast 1992). Furthermore, Gish argues that human vestigial tails are not true tails if they lack vertebrae - an erroneous claim since M. sylvanus is a primate whose fleshy tail also lacks vertebrae (Hill 1974, p. 616; Hooten 1947, p. 23).
Potential Falsification:
These are essentially the same as for vestigial structures above.
Prediction 7: Molecular vestigial characters
Vestigial characters should also be found at the molecular level. Humans do not have the capability to synthesize ascorbic acid (otherwise known as Vitamin C), and the unfortunate consequence can be the nutritional deficiency called scurvy. However, the predicted ancestors of humans had this function (as do most other animals except primates and guinea pigs). Therefore, we predict that humans, other primates, and guinea pigs should carry evidence of this lost function as a molecular vestigial character.
Confirmation:
Recently, the L-gulano-g-lactone oxidase gene, the gene required for Vitamin C synthesis, was found in humans and guinea pigs (Nishikimi, Kawai et al. 1992; Nishikimi, Fukuyama et al. 1994). It exists as a pseudogene, present but incapable of functioning (see prediction 20 for more about pseudogenes).
There are several other examples of vestigial human genes, including multiple odorant receptor genes (Rouquier, Blancher et al. 2000), the RT6 protein gene (Haag, Koch-Nolte et al. 1994), the galactosyl transferase gene (Galili and Swanson 1991), and the tyrosinase-related gene (TYRL) (Oetting, Stine et al. 1993).
Our odorant receptor (OR) genes once coded for proteins involved in now lost olfactory functions. Our predicted ancestors, like other mammals, had a more acute sense of smell than we do now; humans have >99 odorant receptor genes, of which ~70% are pseudogenes. Many other mammals, such as mice and marmosets, have many of the same OR genes as us, but all of theirs actually work. An extreme case is the dolphin, which is the descendant of land mammals. It no longer has any need to smell volatile odorants, yet it contains many OR genes, of which none are functional – they are all pseudogenes (Freitag, Ludwig et al. 1998).
The RT6 protein is expressed on the surface of T lymphocytes in other mammals, but not on ours. The galactosyl transferase gene is involved in making a certain carbohydrate found on the cell membranes of other mammals. Tyrosinase is the major enzyme responsible for melanin pigment in all animals. TYRL is a pseudogene of tyrosinase.
It is satisfying to note that we share these vestigial genes with other primates, and that the mutations that made these genes nonfunctional are also shared with several other primates (see predictions 19-21 for more about shared nonfunctional characters).
Potential Falsification:
It would be very puzzling if we had not found the L-gulano-g-lactone oxidase pseudogene or the other vestigial genes mentioned. In addition, we can predict that we will never find vestigial chloroplast genes in any metazoans (i.e. animals) (Li 1997, pp. 284-286, 348-354).
Prediction 8: Ontogeny and Development of Organisms
Figure 2.8.1. Cat and human embryos in the tailbud stage. A cat embryo is shown on top, a human embryo below. Note the post-anal tail in both, positioned at the lower left below the head of each. The human embryo is about 32 days old.
Embryology and developmental biology have provided some fascinating insights into evolutionary pathways. Since the cladistic morphological classification of species is generally based on derived characters of adult organisms, embryology and developmental studies provide a nearly independent body of evidence.
The ideas of Ernst Haeckel greatly influenced the early history of embryology; however, his ideas have been superseded by those of Karl Ernst von Baer, his predecessor. Von Baer suggested that the embryonic stages of an individual should resemble the embryonic stages of its ancestors (rather than resembling its adult ancestors, a la Haeckel). The final adult structure of an organism is the product of numerous cumulative developmental processes; for species to evolve, there necessarily must have been change in these developmental processes. The macroevolutionary conclusion is that the development of an organism is a modification of its ancestors' ontogenies (Futuyma 1998, pp. 652-653). The modern developmental maxim is the inverse of Haeckel's biogenetic law. "Phylogeny recapitulates Ontogeny," not the opposite. Walter Garstang stated even more correctly that ontogeny creates phylogeny. What this means is that once given knowledge about an organism's ontogeny, we can confidently predict certain aspects of the historical pathway that was involved in this organism's evolution (Gilbert 1997, pp. 912-914). Thus, embryology provides confirmations and predictions about evolution.
Confirmation:
From embryological studies it is known that two bones of a developing reptile eventually form the quadrate and the articular bones in the hinge of the adult reptilian jaw. However, in the marsupial mammalian embryo, the same two structures develop, not into parts of the jaw, but into the anvil and hammer of the mammalian ear. This indicates that during their evolution, the mammalian middle ear bones were derived and modified from the reptilian jaw bones (Gilbert 1997, pp. 894-896).
Accordingly, there is a very complete series of fossil intermediates in which these structures are clearly modified from the reptilian jaw to the mammalian ear (compare the intermediates discussed in prediction 4) (Carroll 1988, pp. 392-396; Futuyma 1998, pp. 146-151; Gould 1990; Kardong 2002, pp. 255-275).
There are numerous other examples where an organism's evolutionary history is represented temporarily in its development, such as mammalian pharyngeal pouches (which are indistinguishable from aquatic vertebrate's gill pouches) and avian teeth (Gilbert 1997, pp. 380, 382).
Potential Falsification:
Based on our standard phylogenetic tree, we may expect to find gill pouches or egg shells at some point in mammalian embryonic development (and we do), and we may expect to find human embryos with tails (and we do; see Figure 2.8.1). However, we never expect to find nipples, hair, or a placenta at any point in fish, amphibian, or reptilian embryos. Likewise, we might expect to find teeth in the mouths of some avian embryos (as we do), but we never expect to find beaks in eutherian mammal embryos (Gilbert 1997, esp. Ch. 23)."
and so forth...
Also, see part 1:
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