Animal C

Comprehensive vocabulary flashcards covering Deuterostome diversity, Chordate characteristics, Vertebrate evolution, and the history of Hominins based on lecture topics.

Deuterostomes

A group of animals distinguished by radial cleavage, a blastopore that becomes the anus, and a coelom developing from mesodermal pockets.

Echinoderms

A clade of marine deuterostomes including sea stars and sea urchins, characterized by pentaradial symmetry in adults and an internal skeleton of calcified plates.

Hemichordates

A clade of marine deuterostomes such as acorn worms and pterobranchs with bilateral symmetry and a three-part body plan (proboscis, collar, trunk).

Chordates

A clade defined by having a dorsal hollow nerve cord, a tail extending beyond the anus, and a notochord at some developmental stage.

Triploblastic

Having three germ layers (ectoderm, mesoderm, and endoderm), a characteristic of all deuterostomes.

Ambulacrarians

The group comprised of echinoderms and hemichordates which typically have ciliated, bilaterally symmetrical larvae.

Pentaradial symmetry

Symmetry in fives or multiples of five, characteristic of adult echinoderms.

Water vascular system

A network of water-filled canals in echinoderms used for gas exchange, locomotion, and feeding.

Tube feet

Extensions of the water vascular system in echinoderms used for movement and capturing prey.

Madreporite

The structure through which water enters the water vascular system of an echinoderm.

Echinozoans

A group of echinoderms including sea urchins and sea cucumbers that typically lack arms.

Asterozoans

A group of echinoderms including sea stars and brittle stars.

Notochord

A dorsal supporting rod found in chordates made of large cells with fluid-filled vacuoles.

Pharyngeal slits

Ancestral chordate features used for filter feeding in tunicates or modified into gills and jaw elements in vertebrates.

Cephalochordates

Also known as lancelets; small marine chordates that retain the notochord throughout their entire life.

Urochordates

Also known as tunicates or sea squirts; chordates that lose the notochord during metamorphosis into sessile adults.

Vertebrates

Chordates characterized by a vertebral column that replaces the notochord and an anterior skull enclosing a brain.

Cyclostomes

A clade of jawless vertebrates consisting of hagfishes and lampreys.

Hagfishes

Jawless fishes with a cartilaginous skeleton, no vertebrae, and the ability to produce large amounts of defensive slime.

Lampreys

Jawless vertebrates with a complete skull and cartilaginous vertebrae; many are parasitic as adults.

Gnathostomes

Vertebrates that possess jaws, which evolved from skeletal gill arches.

Chondrichthyans

Jawed fishes with skeletons made of cartilage, including sharks, rays, and skates.

Osteichthyans

A group of gnathostomes with internal skeletons of calcified, rigid bone.

Ray-finned fishes

Bony fishes with fins supported by rays and a swim bladder used for buoyancy.

Swim bladder

A gas-filled sac in ray-finned fishes used to maintain position at specific depths.

Operculum

A hard flap covering the gills in bony fishes that enhances water flow for respiration.

Lobe-limbed vertebrates

Vertebrates with muscular paired fins or limbs joined by an enlarged bone; the ancestors of tetrapods.

Coelocanths

An ancient lineage of aquatic lobe-fins discovered to still be living in 1938.

Lungfishes

Lobe-limbed vertebrates with both lungs and gills, capable of surviving in mud during droughts.

Tetrapods

The lineage of four-limbed vertebrates that includes amphibians, reptiles, and mammals.

Amphibians

Tetrapods constrained to moist habitats; includes caecilians, frogs (anurans), and salamanders.

Neoteny

The retention of juvenile characteristics in the adult stage, observed in some aquatic salamanders and human skull development.

Amniotes

A group of tetrapods with eggs protected by extraembryonic membranes, allowing for life in dry terrestrial environments.

Yolk

The food supply stored within an amniote egg for the developing embryo.

Synapsids

A major amniote group, characterized by one temporal fenestra, which led to the evolution of mammals.

Archosaurs

A group of reptiles that includes crocodilians, pterosaurs, dinosaurs, and birds.

Lepidosaurs

A group of reptiles including squamates (lizards and snakes) and tuataras with skin covered in horny scales.

Endothermic

The ability to regulate body temperature by producing and retaining metabolic heat, found in birds and mammals.

Theropods

Bipedal predatory dinosaurs from which modern birds descended.

Palaeognaths

A group of secondarily flightless or weak-flying birds like ostriches and emus.

Neognaths

The group containing the majority of modern bird species, most of which retain the ability to fly.

Mammals

Endothermic amniotes with sweat glands, mammary glands, hair, and a four-chambered heart.

Placenta

An organ in eutherian mammals connecting the embryo to the uterus for nutrient and waste exchange.

Prototherians

Monotremes such as the platypus that lay shelled eggs rather than giving birth to live young.

Marsupials

Mammals that carry and feed young in a ventral pouch for further development after an early birth.

Eutherians

Placental mammals where young are more developed at birth than those of marsupials.

Primates

A lineage of eutherians with grasping limbs and opposable digits adapted to arboreal life.

Wet-nosed primates

A clade of primates including lemurs, lorises, and galagos.

Dry-nosed primates

A clade of primates including tarsiers, monkeys, apes, and humans.

Hominin

A clade consisting of modern humans and their extinct relatives, distinguished by bipedal locomotion.

Bipedal locomotion

Walking on two legs, which frees forelimbs and is more energetically economical.

Ardipithecines

The earliest protohominins that exhibited bipedal locomotion.

Australopithecines

Extinct hominins, such as "Lucy" (A.\,afarensis), that descended from ardipithecines.

Homo erectus

The first hominin to leave Africa, characterized by the use of fire and stone tools.

Paleoanthropology

The scientific study of human origins and the evolution of hominins.

Homo neanderthalensis

A large-brained, stocky hominin that lived in Europe and Asia and interbred with early modern humans.

Denisovans

A related lineage to Neanderthals whose genes are found in modern Southeast Asian and Melanesian populations.

Cultural transmission

The passing of knowledge and traditions between generations, allowing societies to change quickly without genetic change.

Viviparity

The process of giving birth to live young rather than laying eggs.

Coevolution

The process where two species evolve in response to each other, such as plants developing spines and herbivores developing specialized teeth.