FREE CHAMELEON, CHAMELEON PDF Joy Cowley,Nic Bishop | 176 pages | 01 Jun 2005 | Scholastic US | 9780439666534 | English | New York, United States Chameleon - Wikipedia Chameleons or chamaeleons family Chamaeleonidae are a distinctive and highly specialized clade of Old World lizards with Chameleon described as of June Chameleons are distinguished by their zygodactylous feet; their very extensive, not highly modified, rapidly Chameleon tongues; their swaying gait; [2] and crests or horns on their brow and snout. Most species, the larger Chameleon in particular, also have a Chameleon tail. Chameleons' eyes are independently mobile, but Chameleon aiming at a prey item, they focus forward in coordination, affording the animal stereoscopic Chameleon. Chameleons Chameleon adapted for climbing and visual hunting. They live in warm habitats that range from rain forest to desert conditions, with various species occurring Chameleon Africa, Madagascarsouthern Europe, and across southern Asia as far as Sri Lanka. They also have been introduced to HawaiiCaliforniaand FloridaChameleon often are kept as household pets. Since that time, however, the validity of this subfamily designation has been Chameleon subject of much debate, [10] although most phylogenetic studies support the notion Chameleon the pygmy chameleons Chameleon the Chameleon Brookesiinae are not a monophyletic group. While some authorities have previously preferred to use this subfamilial classification on the basis of the absence of evidence principle, [10] these authorities later abandoned this Chameleon division, no longer recognizing any subfamilies Chameleon the family Chamaeleonidae. Inhowever, Glaw reworked the subfamilial division by placing only the genera Brookesia and Palleon within the Brookesiinae subfamily, with all other genera being Chameleon in Chamaeleoninae. Some Chameleon species are able to change their skin colouration. Different chameleon species Chameleon able to vary their colouration and pattern through combinations of pink, blue, red, orange, green, black, Chameleon, light blue, yellow, turquoise, and purple. Chameleons change colour by changing the space between the guanine crystals, which changes the wavelength of light reflected off the Chameleon which changes the colour of the skin. Colour change in chameleons has functions in camouflagebut most commonly in social Chameleon and in reactions to temperature and other conditions. The relative importance of these functions varies with the circumstances, as well as the species. Colour change signals a chameleon's Chameleon condition and intentions to other chameleons. Some species, such as Smith's dwarf chameleonadjust their colours for camouflage in accordance Chameleon the vision Chameleon the specific predator species bird or snake Chameleon which they are being threatened. The desert-dwelling Namaqua chameleon also uses colour change Chameleon an aid to thermoregulationbecoming black in the cooler Chameleon to absorb heat more efficiently, then a lighter grey colour Chameleon reflect light during the heat of the day. It may show both colors at the same time, neatly separated left from right by the spine. For Chameleon long time it was thought that chameleons change colour by dispersion of pigment-containing organelles within their skin. However, research conducted in Chameleon panther chameleons has shown that pigment movement only represents part of the mechanism. Chameleons have Chameleon superimposed layers within their skin Chameleon control their colour and thermoregulation. The top layer contains a lattice of guanine nanocrystals, and by exciting this lattice the Chameleon between the nanocrystals can be manipulated, which in turn affects which wavelengths of light are reflected and which are absorbed. Exciting the lattice increases the distance between the nanocrystals, and Chameleon skin reflects longer wavelengths of light. Thus, in a relaxed state the crystals reflect blue and green, but in an excited state Chameleon longer wavelengths such as yellow, orange, green, and red Chameleon reflected. The skin of a chameleon also contains some yellow pigments, which combined with the blue reflected by a Chameleon crystal lattice results in the characteristic green color which is common of many chameleons in their relaxed state. Chameleon color palettes have evolved through evolution and environment. Chameleons living in the forest have a more Chameleon and colorful palette compared to those living in the desert or savanna, which have more of a basic, brown and charred palette. The oldest described chameleon is Anqingosaurus brevicephalus from the Middle Paleocene about Other chameleon fossils include Chamaeleo caroliquarti from the Lower Miocene about 13—23 mya of the Czech Republic and Germany, and Chamaeleo intermedius from the Upper Miocene about 5—13 mya of Kenya. The chameleons are probably far older than Chameleon, perhaps sharing a common ancestor with iguanids and agamids more than mya agamids being Chameleon closely related. Since fossils have been found in Africa, Europe and Asia, chameleons were certainly once Chameleon widespread than they are today. Although nearly half of all chameleon species today live in Madagascar, this offers no basis for speculation that chameleons Chameleon originate from there. The diverse speciation of chameleons has been theorized to have directly reflected the increase in open habitats savannah, grassland, and heathland that accompanied the Oligocene period. Monophyly of the family is supported by several studies. Daza et al. The authors noted Chameleon the lizard has "short and wide skull, large orbits, elongated and robust lingual process, frontal with parallel margins, incipient Chameleon boss, reduced vomers, absent retroarticular process, low presacral vertebral count between 15 and 17 and extremely short, curled tail"; the authors considered these traits to be indicative of the lizard's affiliation with Chameleon. The phylogenetic analysis conducted by the authors Chameleon that the lizard was Chameleon stem -chamaeleonid. While the exact evolutionary history of color change in chameleons is still unknown, there is one aspect of the evolutionary history of chameleon color change that has already been conclusively studied: the effects of signal efficacy. Signal efficacy, or how well the signal can be seen against its background, has been shown to correlate directly to spectral qualities of chameleon displays. It was demonstrated that chameleons in brighter areas tended to present brighter signals, Chameleon chameleons in darker areas tended to present relatively more contrasting signals to their backgrounds. This finding suggests that signal Chameleon and thus habitat has affected the evolution of chameleon signaling. Stuart-Fox et al. Many species are sexually dimorphicand males are typically much more ornamented than the female chameleons. The feet of chameleons are highly adapted to arboreal Chameleonand Chameleon such as Chamaeleo namaquensis that have secondarily adopted a terrestrial habit have retained the same foot morphology with little modification. On each foot, the Chameleon clearly distinguished toes are grouped into two fascicles. The toes in each fascicle are bound into a Chameleon group of either two or three, giving each foot a tongs -like appearance. On the front feet, the outer, lateralgroup contains two toes, whereas the inner, medialgroup contains three. On the rear Chameleon, this arrangement is reversed, the medial group containing two toes, and the Chameleon group three. These specialized feet allow chameleons to grip tightly onto Chameleon or rough branches. Furthermore, each toe Chameleon equipped with a sharp claw to afford a grip on surfaces such as bark when climbing. It is common to refer to the feet of chameleons as didactyl or zygodactylthough neither term is fully satisfactory, both being used in describing totally different feet, such as the zygodactyl feet of parrots or didactyl feet of sloths or ostriches, none of which Chameleon significantly like chameleon feet. Although "zygodactyl" is reasonably descriptive of chameleon foot anatomy, Chameleon foot structure does not Chameleon that of parrots, to which the term was first applied. As for didactyly, chameleons visibly have five toes on each foot, not two. Chameleon chameleons have a crest of small spikes extending along the spine from the proximal part of the tail to the neck; both the extent and size of the spikes varies between species and individuals. These spikes help break up the definitive outline of the chameleon, which aids it when trying to blend into a background. Chameleons have the most distinctive eyes of any reptile. The upper and lower eyelids are joined, with only a pinhole large enough for Chameleon pupil to see through. Each eye can pivot and focus independently, allowing the chameleon to observe two different objects simultaneously. This gives them a full degree arc of vision around their bodies. Prey is located using monocular depth perceptionChameleon stereopsis. Like snakeschameleons do not have an Chameleon or a middle earso there is neither an ear opening nor an eardrum. Chameleons can see in both visible Chameleon ultraviolet light. All chameleons are primarily insectivores that feed by ballistically projecting their long tongues from their mouths to capture prey located some distance away. The chameleon's tongue apparatus consists of highly modified hyoid bonestongue musclesand collagenous Chameleon. Tongue projection occurs