Animal Evolution & Diversity II: Vertebrates Flashcards

Comprehensive vocabulary flashcards covering the characteristics, clades, and evolutionary milestones of vertebrates, fishes, amphibians, reptiles, and mammals as presented in the lecture.

Vertebrates

Chordates with a backbone, comprising approximately $66,000$ species.

Cyclostomes

Jawed fishes including lampreys and hagfish that lack eyes, jaws, and fins.

Gnathostomes

Vertebrates with jaws, which evolved from cartilaginous gill arches.

Tetrapods

Gnathostomes with four limbs, originating approximately $400$ mya during the Devonian period.

Amniotes

Tetrapods with a desiccation-resistant egg, including turtles, lizards, snakes, crocodiles, birds, and mammals.

Mammals

Milk-producing amniotes featuring mammary glands, hair, specialized teeth, and an enlarged skull.

Notochord

A precursor of the backbone that provides support and is replaced by a skeleton in adult vertebrates.

Nerve cord

A hollow tube of nerve tissue that develops into the brain and spinal cord.

Pharyngeal Gill slits

Openings from the mouth to the external environment used for oxygen uptake in fish and appearing in the embryo phase of most taxa.

Hox genes

Clusters of genes that control limb development; humans and all vertebrates have these, and mutations in them can cause large changes in limb development.

Vertebral column

A structure that replaces the notochord and encloses the nerve cord in vertebrates.

Cranium

A structure that encases and protects the brain.

Endoskeleton

The internal skeleton of vertebrates that contains living cells and grows with the animal.

Hagfish

Marine jawless fishes that lack jaws and fins, have a cartilaginous skull, and secrete slime for protection.

Lampreys

Jawless fishes that possess a rudimentary vertebral column consisting of a notochord surrounded by a cartilaginous rod.

Chondrichthyes

Cartilaginous fishes like sharks, skates, and rays that have skeletons made of flexible cartilage rather than bone.

Lateral line

A sensory system in Chondrichthyes that senses movement in surrounding water.

Oviparity

A life cycle where the animal lays eggs.

Ovoviparity

A life cycle where eggs are retained in the female without a placenta (aplacetal).

Viviparity

A life cycle where eggs develop in the uterus and are nourished by a placenta.

Osteichthyes

Bony fishes characterized by a bony skeleton, an operculum, and a swim bladder.

Operculum

A protective flap that covers the gills in bony fishes.

Swim bladder

A gas-filled sac in bony fishes that helps maintain buoyancy.

Actinopterygii

Ray-finned fishes, the most diverse clade of osteichthyes, with fins supported by thin, bony, flexible rays.

Sarcopterygii

Lobe-finned fishes with fins supported by skeletal extensions moved by muscles within the fins.

Buccal pumping

A breathing method used by amphibians to drive air into the lungs by gulping air.

Anura

The amphibian order including frogs and toads, characterized by carnivorous adults and the absence of a tail.

Apoda

The amphibian order of wormlike caecilians that are nearly blind and secondarily legless.

Urodela

The amphibian order of salamanders, which have legs, a long tail, and an elongate body.

Albumin

The egg white in an amniotic egg that surrounds the chorion and stores nutrients.

Testudines

The reptile order of turtles, characterized by a hard protective shell to which vertebrae and ribs are often fused.

Squamata

The reptile order including lizards and snakes, characterized by a kinetic skull with extremely mobile joints.

Crocodilia

Large carnivorous aquatic reptiles including crocodiles and alligators, featuring a four-chambered heart and parental care.

Archaeopteryx lithographica

An intermediate fossil between dinosaurs and birds that featured clawed forelimbs, teeth, and feathers.

Air sacs

Nine large, hollow sacs in birds that expand and contract to allow constant, efficient movement of air across the stationary lungs.

Endotherms

Animals, such as birds and mammals, that maintain a warm internal body temperature; birds range from $40\text{-}42^{\text{o}}\text{C}$.

Monotremata

A subclass of mammals (Prototheria) that lay eggs and lack a placenta; includes the duck-billed platypus and echidnas.

Marsupials

Mammals (Metatheria) where young are born extremely small and develop further in a ventral pouch called a marsupium.

Eutherians

Placental mammals with a long-lived, complex placenta and a prolonged gestation period.

Thoracic breathing

A type of breathing in amniotes where muscle contractions expand the rib cage to draw in air.