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Figure 1:In mammals, the quadrate and articular bones are small and part of the middle ear; the lower jaw consists only of dentary bone.. While living mammal species can be identified by the presence of milk-producing mammary glands in the females, other features are required when classifying fossils, because mammary glands and other soft-tissue features are not visible in fossils.
An evolutionary tree (of Amniota, for example, the last common ancestor of mammals and reptiles, and all its descendants) illustrates the initial conditions causing evolutionary patterns of similarity (e.g., all Amniotes produce an egg that possesses the amnios) and the patterns of divergence amongst lineages (e.g., mammals and reptiles ...
A mammal (from Latin mamma 'breast') [1] is a vertebrate animal of the class Mammalia (/ m ə ˈ m eɪ l i. ə /).Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones.
[4] [5] Charles Darwin more famously proposed the theory of universal common descent through an evolutionary process in his book On the Origin of Species in 1859: "Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first ...
Pelycosaur (/ ˈ p ɛ l ɪ k ə ˌ s ɔːr / PEL-ih-kə-sor) [1] is an older term for basal or primitive Late Paleozoic synapsids, excluding the therapsids and their descendants. Previously, the term mammal-like reptile had been used, [2] and pelycosaur was considered an order, but this is now thought to be incorrect and outdated.
Flowering plants (Delphinium, Aerangis, Tropaeolum and others) from different regions form tube-like spurs that contain nectar. This is why insects from one place sometimes can feed on plants from another place that have a structure like the flower, which is the traditional source of food for the animal. [218]
Evolution of dinosaurs – Archosaurian reptiles that dominated the Mesozoic Era. Evolution of birds – Derivation of birds from a dinosaur precursor; Evolution of mammals – Derivation of mammals from a synapsid precursor, and the adaptive radiation of mammal species Evolution of cetaceans
Reptiles, in the traditional sense of the term, are defined as animals that have scales or scutes, lay land-based hard-shelled eggs, and possess ectothermic metabolisms. So defined, the group is paraphyletic , excluding endothermic animals like birds that are descended from early traditionally-defined reptiles.