taxon_rank hagryphus
The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period million years ago ( Mya ) to the beginning of the Paleogene Period Mya . It is the last period of the Mesozoic Era . The Cretaceous Period is usually abbreviated K , for its German translation " Kreide " ( chalk ). Chalk is a soft , white , porous , sedimentary carbonate rock , a ___MASK83___ of limestone composed of the mineral calcite . Calcite is an ionic salt called calcium carbonate or CaCO . It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells ( coccoliths ) shed from micro - organisms called coccolithophores . Flint ( a type of chert unique to chalk ) is very common as bands parallel to the bedding or as nodules embedded in chalk . It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction . Flint is often deposited around larger fossils such as Echinoidea which may be silicified ( i . e . replaced molecule by molecule by flint ). The Triassic  Jurassic extinction event marks the boundary between the Triassic and Jurassic periods , , and is one of the major extinction events of the Phanerozoic eon , profoundly affecting life on land and in the oceans . In the seas , a whole ___MASK32___ ( conodonts ) and 34 % of marine genera disappeared . On land , all pseudosuchians ( non - ornithodiran archosaurs ) other than crocodylomorphs ( Sphenosuchia and Crocodyliformes ), some remaining therapsids , and many of the large amphibians became extinct . A symbol is a mark , sign , or word that indicates , signifies , or is understood as representing an idea , object , or relationship . Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different concepts and experiences . All communication ( and data processing ) is achieved through the use of symbols . Symbols take the ___MASK83___ of words , sounds , gestures , ideas or visual images and are used to convey other ideas and beliefs . For example , a red octagon may be a symbol for " STOP ". On a map , a blue line might represent a river . Numerals are symbols for numbers . Alphabetic letters may be symbols for sounds . Personal names are symbols representing individuals . A red rose may symbolize love and compassion . The variable ' x ', in a mathematical equation , may symbolize the position of a particle in space . The griffin , griffon , or gryphon ( Greek :  , " grýphn ", or  , " grýpn ", early ___MASK83___ "  ", " grýps ") is a legendary creature with the body , tail , and back legs of a lion ; the head and wings of an eagle ; and an eagle ' s talons as its front feet . Because the lion was traditionally considered the king of the beasts and the eagle the king of birds , the griffin was thought to be an especially powerful and majestic creature . The griffin was also thought of as king of all creatures . Griffins are known for guarding treasure and priceless possessions . Adrienne Mayor , a classical folklorist , proposes that the griffin was an ancient misconception derived from the fossilized remains of the " Protoceratops " found in gold mines in the Altai mountains of Scythia , in present - day southeastern Kazakhstan , or in Mongolia , though this hypothesis has been strongly contested as it ignores pre - Mycenaean accounts . In antiquity it was a symbol of divine power and a guardian of the divine . Protoceratops ( from Greek " proto -/  -" " first ", " cerat -/  -" " horn " and "- ops /-  " " face ", meaning " First Horned Face ") is a ___MASK71___ of sheep - sized ( 1 . 8 m long ) herbivorous ceratopsian dinosaur , from the Upper Cretaceous Period ( Campanian stage ) of what is now Mongolia . It was a member of the Protoceratopsidae , a group of early horned dinosaurs . Unlike later ceratopsians , however , it was a much smaller creature that lacked well - developed horns and retained some primitive traits not seen in later genera . The Triassic is a geologic period and system which spans 50 . 9 million years from the end of the Permian Period million years ago ( Mya ), to the beginning of the Jurassic Period Mya . The Triassic is the first period of the Mesozoic Era . Both the start and end of the period are marked by major extinction events . The Triassic was named in 1834 by Friedrich von Alberti , after the three distinct rock layers (" tri " meaning " three ") that are found throughout Germany and northwestern Europe  red beds , capped by marine limestone , followed by a ___MASK86___ of terrestrial mud - and sandstones  called the " Trias ". Dinosaurs are a diverse ___MASK10___ of animals of the clade Dinosauria that first appeared during the Triassic . Although the exact origin and timing of the evolution of dinosaurs is the subject of active research , the current scientific consensus places their origin between 231 and 243 million years ago . They became the dominant terrestrial vertebrates after the Triassic  Jurassic extinction event 201 million years ago . Their dominance continued through the Jurassic and Cretaceous periods and ended when the Cretaceous  Paleogene extinction event led to the extinction of most dinosaur groups 66 million years ago . A clade ( from , " klados ", " ___MASK80___ ") is a ___MASK10___ of organisms that consists of a common ancestor and all its lineal descendants , and represents a single " ___MASK80___ " on the " tree of life ". The lion (" Panthera leo ") is one of the big cats in the ___MASK71___ " Panthera " and a member of the family Felidae . The commonly used term African lion collectively denotes the several subspecies in Africa . With some males exceeding in weight , it is the second - largest living cat after the tiger . Wild lions currently exist in sub - Saharan Africa and in India ( where an endangered remnant population resides in Gir Forest National Park ). In ancient historic times , their range was in most of Africa , including North Africa , and across Eurasia from Greece and southeastern Europe to India . In the late Pleistocene , about 10 , 000 years ago , the lion was the most widespread large land mammal after humans : " Panthera leo spelaea " lived in northern and western Europe and " Panthera leo atrox " lived in the Americas from the Yukon to Peru . The lion is classified as a vulnerable species by the International Union for Conservation of Nature ( IUCN ), having seen a major population decline in its African range of 30  50 % over two decades during the second half of the twentieth century . Lion populations are untenable outside designated reserves and national parks . Although the cause of the decline is not fully understood , habitat loss and conflicts with humans are the greatest causes of concern . Within Africa , the West African lion population is particularly endangered . Hagryphus ( `` Ha ' s griffin '' ) , is an oviraptorosaurian theropod dinosaur from the Upper Cretaceous Period of what is now Utah . The Paleogene ( or ; also spelled Palaeogene or Palæogene ; informally Lower Tertiary ) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya ) to the beginning of the Neogene Period Mya . It is the beginning of the Cenozoic Era of the present Phanerozoic Eon . The Paleogene is most notable for being the time during which mammals diversified from relatively small , simple forms into a large ___MASK10___ of diverse animals in the wake of the Cretaceous  Paleogene extinction event that ended the preceding Cretaceous Period . In biology and ecology , extinction is the end of an organism or of a ___MASK10___ of organisms ( taxon ), normally a ___MASK57___ . The moment of extinction is generally considered to be the death of the last individual of the ___MASK57___ , although the capacity to breed and recover may have been lost before this point . Because a ___MASK57___ ' potential range may be very large , determining this moment is difficult , and is usually done retrospectively . This difficulty leads to phenomena such as Lazarus taxa , where a ___MASK57___ presumed extinct abruptly " reappears " ( typically in the fossil record ) after a period of apparent absence . Eagle is a common name for many large birds of prey of the ___MASK63___ Accipitridae ; it belongs to several groups of genera that are not necessarily closely related to each other .