BIO2206 Biology of Animals: Vertebrates

These flashcards provide vocabulary and definitions covering the biology of vertebrates, including their evolution, classification, and distinct physiological characteristics of chordates, fishes, amphibians, reptiles, birds, and mammals.

Vertebrates

A group of animals characterized by an endoskeleton with a backbone, a distinct skull (cephalization), triploblastic development, and a closed circulatory system with chambered hearts.

Deuterostomes

A broad group of animals, including Echinodermata and Chordata, characterized by specific embryonic development patterns.

Notochord

A flexible, hydrostatic organ extending the length of the body in chordates that provides skeletal support and allows for undulatory movements.

Nerve cord

A dorsal tube in chordates located above the digestive tract that gives rise to the spinal cord and brain.

Pharyngeal slits

Chordate structures used for filter feeding and gill support, which form components of ears and tonsils in tetrapods.

Post anal tail

A chordate characteristic used for locomotion in aquatic species and balance, courting, or communication in tetrapods.

Urochordata

A subphylum commonly called tunicates or tail-chordates, which are mostly sessile as adults and possess a non-living tunic containing cellulose.

Ascidiacea

The most common class of Urochordata, known as sea squirts, which are typically sessile and use incurrent and excurrent siphons for filter feeding.

Cephalochordata

A subphylum of slender, bladelike animals called lancelets that inhabit sandy coastal sediments and lack a true brain.

Atripore

The opening in Cephalochordates through which water and gametes are released to the outside.

Myllokunmingia and Haikouichthys

Two of the earliest known fish-like vertebrates discovered in China, dating back to the Cambrian period.

Ostracoderms

The first vertebrates to possess bony armor, appearing as jawless fish during the Silurian period.

Placoderms

The first group of jawed vertebrates, radiating in the Devonian period, characterized by bony plates and efficient predation.

Agnatha

A superclass of jawless fishes, including hagfishes ($Myxini$) and lampreys ($Petromyzontida$), lacking internal ossification and scales.

Myxini

A group of blind, soft-skinned jawless fish known as hagfishes that lack vertebrae and produce slime.

Petromyzontida

A group of parasitic jawless fish known as lampreys that spawn in freshwater and have an ammocoete larval stage.

Chondrichthyes

A class of vertebrates featuring cartilaginous skeletons, polyphyodont teeth, large oil-filled livers, and internal fertilization via claspers.

Elasmobranchii

A subclass of Chondrichthyes that includes sharks, skates, and rays.

Holocephali

A subclass of Chondrichthyes consisting of chimaeras, also known as ratfish, which have jaws bearing large flat plates instead of teeth.

Lateral line

A sensory system in fishes consists of a series of pores or receptors that detect vibrations and pressure changes in water.

Osteichthyes

The most species-rich group of vertebrates ($>30,000$ species), known as bony fishes, characterized by a calcified skeleton and an operculum covering the gills.

Swim bladder

A gas-filled sac in most bony fishes used to control buoyancy and move up and down in the water column.

Actinopterygii

The subclass of ray-finned fishes, named for fins supported by parallel bony rays, comprising the majority of modern fish species.

Sarcopterygii

The subclass of lobe-finned fishes, including lungfishes and coelacanths, which possess muscular pectoral and pelvic lobes and are ancestors to amphibians.

Amphibia

The first group of living vertebrates to adapt to land, typically characterized by cutaneous respiration, moist glandular skin, and a partially divided heart.

Gymnophiona

The order of limbless, burrowing amphibians known as caecilians.

Urodela

The order of tailed amphibians, such as salamanders and newts, which are often carnivorous as both larvae and adults.

Anura

The order of tailless amphibians including frogs and toads, which are specialized for jumping and typically have a tadpole larval stage.

Amniotic egg

A major reptilian adaptation featuring four membranes (amnion, allantois, chorion, and yolk sac) that allows for reproduction in dry habitats.

Anapsid skull

A ancestral skull pattern with no temporal openings, historically associated with turtles.

Diapsid skull

A skull pattern characterized by two pairs of temporal openings, found in birds, lizards, snakes, and crocodiles.

Synapsid skull

A skull pattern with a single pair of lateral temporal openings, characteristic of the lineage that gave rise to mammals.

Testudines

The reptile order comprising turtles, characterized by a dorsal carapace and ventral plastron and the absence of teeth.

Squamata

The largest order of reptiles, including lizards ($Lacertilia$), snakes ($Serpentes$), and amphisbaenians.

Sphenodonta

The order of lizard-like reptiles known as tuataras, represented by two living species with extremely slow reproduction rates.

Crocodilia

An order of large, robust reptiles including alligators and crocodiles, featuring a complete secondary palate and providing parental care to eggs.

Aves

The class of endothermic vertebrates distinguished by feathers, beaks without teeth, and forelimbs modified into wings.

Archaeopteryx

An extinct prehistoric animal considered the earliest known bird and an evolutionary link between dinosaurs and modern birds.

Mammalia

A class of endothermic vertebrates defined by the presence of hair, mammary glands, a diaphragm, and diphyodont teeth.

Monotremes

A group of oviparous (egg-laying) mammals.

Marsupials

A group of viviparous mammals whose young complete development in a pouch.

Placental mammals

Advanced mammals characterized by a placenta that allows the young to be born at a more advanced stage of development.