Evolutionists say that the oldest reptilian fossils are found in rocks from ---, dating to the late --- period; they are said to be about 300 million years old.
Evolutionists say that the ancestor of reptiles was among the --- amphibians.
Evolutionists say that the first major reptilian radiation occurred by the dawn of the ---, the last period of the --- era, giving rise to the three main branches: Synapsida, Anapsida, Diapsida.
Evolutionists say that the second great reptilian radiation was underway by late --- times (a little more than 200 million years ago) and was marked mainly by the origin and diversification of the two groups: dinosaurs and ---.
--- had wings formed from a membrane of skin stretched from the body wall, along the forelimb, to the tip of an elongated finger.
(Pterosaurs) Stiff fibers provided support for the --- of the wing.
There were two main dinosaur lineages: the --- and the saurischians.
There is continuing debate about whether dinosaurs were ---, capable of keeping the body warm through ---.
Evolutionists say that the --- climate was relatively warm and consistent.
Large dinosaurs had --- surface-to- volume ratios that reduced the effects of daily fluctuations in air temperature on the internal temperature of the animal.
The --- dinosaur lineage is mostly herbivorous.
The --- has both herbivorous and carnivorous dinosaurs. (Evolutionists say that this line contains the ancestors of birds.)
Evolutionists say that the dinosaur that gave rise to birds was certainly ---, as are all birds.
Evolutionists say that at the end of the ---, the last period of the Mesozoic era, the --- became extinct.
4 Reptile Groups: turtles
4 Reptile Groups: tuataras
4 Reptile Groups: lizards and snakes
4 Reptile Groups: alligators and crocodiles
Evolutionists say that vestigial --- and limb bones in primitive snakes such as boas are evidence that snakes evolved from reptiles with legs.
Poisonous snakes inject their toxin through a pair of sharp --- or --- teeth.
(Reptilia) Snakes. The flicking tongue is not poisonous but helps fan odors toward --- organs on the roof of the mouth.
--- --- jaws enable most snakes to swallow prey larger than the diameter of the snake itself.
Evolutionists say that among reptiles, --- are the most closely related to dinosaurs.
Evolutionists say that the modern animals that share the most recent ancestor with the dinosaurs are the ---.
(Birds) The bones have an internal structure that is ---, making them strong but light.
(Birds) Females have only --- ovary.
Birds are ---less. Food is not chewed in the mouth, but ground in the ---.
(Birds) Crocodiles also have ---.
(Birds) An efficient respiratory system and a circulatory system with a --- -chambered heart keep tissues well supplied with oxygen and nutrients, supporting a high rate of ---.
(Birds) The --- have tiny tubes leading to and from elastic air sacs that help dissipate heat and reduce the density of the body.
Bird wings are ---, structures whose shape creates lift by altering air currents.
(Birds) The --- edge of an airfoil is thicker than the --- edge, its upper surface is somewhat convex, its undersurface is flattened or concave.
(Birds) The shape of the bird's wing causes the air passing over the wing to travel farther than the air passing under the wing. As a result, air molecules are spaced farther apart (---) above the wing than below it.
(Birds) The air pressure pushing downward on the wing is less than the pressure pushing upward on the wing's bottom surface. This pressure --- provides the 'lift' for flight.
(Birds) A feather consists of a central hollow shaft, from which radiate the ---.
(Birds) Feather vanes are made up of barbs, in turn bearing even smaller branches called ---.
Birds have --- feathers and downy feathers.
--- feathers are the stiff ones that contribute to the aerodynamic shapes of the wings and body.
Contour feather barbules have hooks that cling to barbules on neighboring ---. When a bird preens, it runs the length of a feather through its bill, engaging the hooks and uniting the barbs into a precisely shaped ---.
--- feathers lack hooks, and the free-form arrangement of --- produces a fluffiness that provides excellent insulation because of the trapped air.
Birds flap their wings by contractions of large --- (breast) muscles anchored to a keel on the --- (breastbone).
Feathers and beaks are made of ---.
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