Chapter 34: The Origins And Evolution Of Vertebrates Flashcards
Chordate
Animal that at some point during their development have a notochord, pharyngeal slit or cleft, and a muscular post anal tail.
Notochord
A longitudinal, flexible rod made of tightly packed mesodermal cells that runs along the anterior-posterior axis of a chordate in the dorsal part of the body
Pharyngeal clefts
In chordate embryos, one of the grooves that seperate a series of arches along the outer surface of the pharynx and may develop into a pharyngeal slit
Pharyngeal slit
In chordate embryos, one of the slits that forms from the pharyngeal clefts and opens into the pharynx, later developing into gill slits in many vertebrates
Lancelets
A small blade-shaped marine chordate that lacks a backbone
Tunicates
A sessile marine chordate that lacks a backbone
Neural Crest
In vertebrates, a region located along the sides of the neural tube where it pinches off from the ectoderm. Neural crest cells migrate to various parts of the embryo and form pigment cells in the skin and parts of the skull, teeth, adrenal glands, and peripheral nervous system
hagfishes
Marine jawless vertebrate that have highly reduced vertebrae and a skull made of cartilage; most are bottom-dwelling scavengers
Lamprey
Any of the jawless vertebrates with highly reduced vertebrae that live in freshwater and marine environments. Almost half of extant lamprey species are parasites.
Cyclostomes
Lack jaws; includes lampreys and hagfishes
Conodont
An early, soft bodied vertebrate with prominent eyes and dental elements
Gnathostome
Have jaws and include sharks, rays, amphibians, reptiles, and mammals
Lateral Line system
A mechanoreceptor system consisting of a series of pores and receptor units along the sides of the body in fishes and aquatic amphibians; detects water movements made by the animal itself and by other moving objects
Placoderm
A member of an extinct group of fishlike vertebrates that had jaws and were enclosed in a tough outer armor
Acanthodians
Any of a group of ancient jawed aquatic vertebrates from the Silurian and Devonian periods
Chondrichthyes
Referring to a type of development in which young hatch from eggs that are retained in the mother’s uterus
Viviparous
Referring to a type of development in which the young are born alive after having been nourished in the uterus by blood from the placenta
Cloaca
A common opening for the digestive, urinary, and reproductive tracts found in many non mammalian vertebrates but in few mammals
Osteichthyan
A member of a vertebrate clade with jaws and mostly bony skeletons
Operculum
In aquatic osteichthyans, a protective bony flap that covers and protects the gills
Swim Bladder
In aquatic osteichthyans, an air sac that enables the animal to control its buoyancy in the water
Ray-finned fishes
Aquatic osteichthyans with fins supposed by long, flexible rays, including tuna, bass, and herring
Lobe-fins
Osteichthyans having rod-shaped muscular fins. The group includes lungfishes and tetrapods
tetrapods
A vertebrate clade whose members have limbs with digits. Includes mammals, amphibians, and birds and other reptiles
Amphibian
A member of the clade of tetrapods that includes salamanders, frogs, and caecilians
Amniote
A member of a clade of tetrapods named for a key derived character, the amniotic egg, which contains specialized membranes, including the fluid-filled amnion that protects the embryo. Amniotes include mammals as well as birds and other reptiles
Amniotic Egg
An egg that contains specialized membranes that function in protection, nourishment, and gas exchange. The amniotic egg was a major evolutionary innovation, allowing embryos to develop on land in a fluid-filled sac, this reducing the dependence of tetrapods on water for reproduction.
Reptiles
A member of the clade of amniotes that includes tuataras, lizards and snakes, turtles, crocodilians, and birds
Ectothermic
Referring to organisms for which external sources provide most of the heat for temperature regulation
Endothermic
Referring to organisms that are warmed by heat generated by their own metabolism. This heat usually maintains a relatively stable body temperature. Higher than that of the external environment
Diapsid
A member of an amniote clade distinguished by a pair of holes on each side of the skull
Lepidosaur
A member of the reptilian group that includes lizards, snakes, and two species of New Zealand animals called tuataras
Archosaurs
A member of the reptilian group that includes crocodiles, alligators, and dinosaurs, including birds
Pterosaur
Winged reptile that lived during the Mesozoic Era
Dinosaurs
A member of an extremely diverse clade of reptiles varying in body shape, size and habitat.
Birds are the only extant dinosaurs
Theropod
A member of a group of dinosaurs that were bipedal carnivores
Ratite
A member of the group of flightless birds
Mammals
Amniotes that have hair and mammary glands
Synapsids
A member of an amniote clade distinguished by a single hole on each side of the skull
Monotreme
An egg-laying mammal, such as platypus to echidna. Monotremes have hair and produce milk, but they lack nipples
Marsupial
A mammal, such as a koala, whose young complete their embryonic development inside a maternal pouch called the marsupium
Placenta
A structure in the uterus of a pregnant eutherian mammal that nourishes the fetus with the mother’s blood supply; formed from the uterine lining and embryonic membranes.
Eutherian
Placental mammals whose young complete their embryonic development within the uterus, joined to the mother by the placenta
Opposable Thumb
A thumb that can touch the ventral surface of the fingertip of all four fingers of the same hand with its own ventral surface
Anthropoids
A member of a primate group made up of the monkeys and apes
Paleoanthropology
The study of human origins and evolution
Hominin
A group consisting of humans and the extinct species that are more closely related to us than to chimpanzees
