Radiation and Homology, Part 2 (Reptiles to Mammals)

Vocabulary flashcards covering key terms from the lecture notes on reptiles to mammals.

Amniota

Group of tetrapods (reptiles, birds, and mammals) that reproduce with extra-embryonic membranes enabling terrestrial life.

Amnion

Embryo-surrounding membrane that secretes fluid to keep the embryo moist.

Chorion

Embryonic membrane containing blood vessels that allows gas exchange.

Allantois

Embryonic membrane that stores waste products.

Yolk sac

Embryonic membrane surrounding the yolk, providing nutrients early in development.

Hylonomus

An early Carboniferous reptile among the earliest reptiles.

Carboniferous Rainforest Collapse

Event around 305 million years ago that led to drier conditions and the rise of the Age of Reptiles.

Occipital condyle

Single skull opening at the base of the skull that articulates with the spine; characteristic of early reptiles.

Neck

Evolutionary development of a cervical region with vertebrae enabling head movement.

Pelvis

Pelvic girdle that articulates with sacral vertebrae to support powerful hindlimbs.

Diapsida

Reptile group with two temporal skull openings behind the eyes.

Lepidosaurs

Lizards and snakes.

Archosaurs

Reptiles including dinosaurs, crocodiles, and birds (excluding turtles in some schemes).

Synapsida

Vertebrate group with one temporal skull opening; lineage leading to mammals.

Anapsida

Group with no temporal skull openings.

Saurischians

Dinosaur group with lizard-like hip structure; includes ancestors of birds.

Ornithischians

Dinosaur group with bird-like hip structure.

Archaeopteryx

Late Jurassic transitional fossil between dinosaurs and birds, illustrating early flight features.

Aves

Modern birds; features include endothermy, feathers, hollow bones, nesting/brooding.

Gastroliths

Stones swallowed to aid digestion in some birds and dinosaurs.

Pelycosaurs

Early synapsids, ancestors of therapsids and mammals.

Therapsids

Advanced synapsids; mammal-like traits that precede true mammals.

Heterodont dentition

Teeth of different shapes (incisors, canines, premolars, molars) for processing food.

Juramaia sinensis

Early eutherian mammal (about 160 million years old) significant for placental evolution.

Platypus

Monotreme mammal with venomous spurs in males; represents a transitional form toward other mammals.

Monotremes

Egg-laying mammals including platypus and echidnas.

Eutheria

Placental mammals; includes most living mammal species.

Metatheria

Marsupials; development primarily in a pouch after short gestation.

Afrotheria

Clade of mostly African-origin mammals (e.g., elephants, manatees, hyraxes, aardvarks).

Euarchontoglires

Clade including Primates, Rodentia, Lagomorpha, and related groups.

Laurasiatheria

Clade including Cetacea, Carnivora, Perissodactyla, Artiodactyla, Chiroptera, and others.

Artiodactyla

Even-toed ungulates (deer, cattle, pigs, camels, etc.).

Perissodactyla

Odd-toed ungulates (horses, tapirs, rhinos).

Cetacea

Whales, dolphins, and porpoises; adapted to an aquatic lifestyle with re-evolved tail and echolocation.

Carnivora

Order including cats, dogs, bears, and relatives; diverse feeding strategies.

Chiroptera

Bats; the only mammals capable of powered flight; forelimbs modified for flight.

Insectivora

Historically grouped insect-eating mammals (moles, shrews, hedgehogs); classification is contentious.

Ossicles

Three middle ear bones (malleus, incus, stapes) that enhance hearing in mammals.

Endothermy

Warm-blooded metabolism; maintenance of stable body temperature independent of environment.