Comparative Test 1

Comparative anatomy vocab for test I

teleologist

evolutionary adaptations, functions and processes suggesting that biological structures exist for a specific purpose

homology

similarity in characteristics, DNA, or function, between different organism, inherited from a common ancestor

archetype

the fundamental, ideal structural pattern or "blueprint" which a natural group of organisms is assumed to be constructed

morphology

the form, shape, size and structure of organisms

form

physical structure, shape, size and anatomical arrangement of an organism, including components and external appearance

function

action, role, or physiological activity performed by a structure that contributes to the survival, growth and reproduction of an organism

taxonomy

the science of naming, describing and classifying living and extinct organisms into a hierarchical system based on shared characteristics

binomial nomenclature

formal, standardized system of naming species using two latinized terms: the genus and the specific epithet

linnean ranks

domain, kingdom, phylum, class, order, family, genus and species

phylogeny

the study of evolutionary history, relationships and divergence of species or groups of organisms over time

phylogenetic tree

a branching diagram that represents the evolutionary relationships and common ancestry among different biological species or taxa

terminals

the organisms, species, or sequences located at the very ends of the branches on a phylogenetic tree

nodes

the branching points on a phylogenetic tree or cladogram, representing the most recent common ancestor of subsequent lineages

taxon

a named group or unit of organisms placed at the tips of the branches, representing a specific point in evolutionary history

monophyletic group

a taxonomic group on a phylogenetic tree consisting of a common ancestor and all of its lineal descendants

clade

a grouping that includes a common ancestor and all of its descendants, living and extinct

paraphyly

taxonomic grouping that includes a common ancestor and some, but not all, of its descendants

synapomorphies

a shared, derived character state inherited from a common ancestor that is used to define and group monophyletic taxa in biological classification

plesiomorphies

ancestral character states inherited from a distant common ancestor that are retained within a clade

preadaptation

an existing trait in an organism that, by chance becomes advantageous for a new function or environment, often serving as the raw material for future evolutionary change

serial homology

the evolutionary and developmental relationship where repeated, segmented structures within a single organism (such as vertebrae, limbs, or leaves) share a common ancestral form but have been modified to perform different functions

analogy

similarity in function or appearance between structures in different species that do not share a common ancestor, these structures evolve independently through convergent evolution

convergent evolution

the independent evolution of similar features, traits or body forms in unrelated organisms to adapt to similar environmental pressures

radial cleavage

in deuterostomes, where blastomeres divide symmetrically, aligning directly on top of one another around the polar axis

blastopore

the first opening that forms in an embryo during gastrulation, marking the site where the archenteron (primitive gut) connects to the exterior

enterocoele

embryonic coelom forms

coelom

a fluid-filled cavity that is completely lined with mesoderm-derived tissue

mesodermal skeleton

internal supporting structure derived from the mesoderm, the middle germ layer of an embryo

cephalochordata

marine invertebrates, that are considered the most basal chordates

tunicata (urochordata)

marine invertebrate chordates characterized by a tough, cellulose like outer covering called tunic

vertebrata (craniata)

chordate animals defined by having a segmented backbone or spinal column, a bony cartilaginous skeleton and a brain enclosed within a skull

myomeres

segmented blocks of skeletal muscle tissue arranged longitudinally along the sides of fish, larval amphibians and cephalochordates

endostyle

a ciliated, longitudinal groove on the ventral wall of the pharynx in invertebrate chordates and lamprey larvae, it traps food particles during filter feeding, precursor to thyroid gland

notochord

flexible, rod shaped structure made of cartilage like material that serves as the primary axial support in the embryos of all chordates

dorsal hollow nerve cord

a fluid filled tube of nervous tissue that runs along the back (dorsal side) of the organism

postanal tail

posterior extension of the body extending beyond the anus

pharyngeal slits

paired openings in the pharynx, they function in filter-feeding and respiration in aquatic organisms. In vertebrates, these structures evolve, including gill supports in fish and components of the ear and throat in tetrapods

dorsal fins

located on the backs of fish and marine mammals, function primarily as stabilizers that prevent rolling and assist in sharp turns

caudal fins

tail fin

ventral/pelvic fins

a pair of fins located on the underside or belly of a fish, typically positioned behind or below the pectoral fins. These fins are essential for stability, braking, and steering, acting as a counterpart to hind limbs in tetrapods

oral hood

a specialized, funnel-shaped, muscular membrane that surrounds the mouth in cephalochordates. It acts as a feeding apparatus, directing food-laden water into the mouth while using fringed, sensory tentacles called buccal cirri to filter out large particles

velar tentacles

specialized, sensory, and protective, hair-like appendages located on the velum (a membrane) in the oral region of certain chordates, they act as a filter to prevent large, undesirable particles or debris from entering the pharynx and digestive cavity

wheel organ

a specialized, ciliated epithelium in the oral cavity of cephalochordates that creates water currents to sweep food particles into the mouth. It is often found in the roof and sides of the buccal cavity and is part of their filter-feeding mechanism

epipharyngeal grooves

embryonic grooves in the pharyngeal (throat) region of vertebrate embryos that help guide the development of structures such as gills or parts of the ear and neck, depending on the species

midgut caecum

finger-like sacs off the midgut that help with digestion and absorption

tunic

a protective outer covering or layer of an organ or organism

incurrent siphon

a tube-like opening in some aquatic animals (like clams and other bivalves) that draws water into the body, bringing in oxygen and food particles for respiration and feeding.

ganglion

a group of nerve cells that acts as a relay station for information

hermaphrodites

an individual with both male and female reproductive capabilities

atrium

a chamber or cavity that receives fluid, especially the upper chambers of the heart that receive blood before passing it to the ventricles

excurrent siphon

a tube-like opening in aquatic animals (like clams and other bivalves) that expels water out of the body after oxygen and food have been removed

adhesive papillae

small, sticky structures used by some organisms to attach to a surface, especially during early development

vertebrae

the individual bones that make up the vertebral column (spine) in vertebrate animals, protecting the spinal cord and providing structural support

cranium

the part of the skull that encloses and protects the brain

lateral line

a sensory system in fish and some amphibians consisting of a line of specialized organs along the body that detect water movements and vibrations

electroreceptive systems

specialized sensory systems in certain animals (like sharks, rays, and some fish) that detect electrical fields generated by other organisms or the environment

neurogenic placodes

thickened regions of embryonic ectoderm that give rise to sensory neurons and sensory structures, such as parts of the eyes, ears, and nose

forebrain

the anterior (front) part of the brain responsible for processing sensory information, voluntary movement, and higher cognitive functions

midbrain

the middle part of the brain connecting the forebrain and hindbrain, involved in vision, hearing, motor control, and alertness

hindbrain

the posterior (rear) part of the brain that controls balance, coordination, and vital autonomic functions

gill arches

bony or cartilaginous curved structures in the pharyngeal region of fish and some vertebrate embryos that support the gills

neural crest

a group of embryonic cells that form along the edges of the neural tube and migrate to give rise to diverse structures, including parts of the peripheral nervous system, facial cartilage, and pigment cells

semicircular duct

fluid-filled tubes in the inner ear that detect rotational movements of the head and help maintain balance

ammocoete

larval stage of lampreys

Ostracoderms

extinct, jawless fishes, presence of bone, dorsal/ventral head shields, no pectoral fins

Osteoostracans

extinct, large head shield, paired pectoral fins, heterocercal tail, single median nostril, unique cephalic fields

pectoral fins

paired fins located on the sides of a fish or aquatic vertebrate near the head, used for steering, balance, and maneuvering

heterocercal tail

a tail with a larger top lobe that helps with swimming and lift

cephalic fields

regions in the developing embryo that give rise to the head structures, including brain, sensory organs, and facial tissues

cartilage

a tough, flexible, and avascular connective tissue that acts as a structural component, shock absorber, and friction-reducing surface in the body

sarcopterygii

lobe-finned fish, a class of bony fish with fleshy, lobed fins that are connected to the body by a single bone, including coelacanths and lungfish, and ancestral to tetrapods

actinopterygii

ray-finned fish, a class of bony fish with fins supported by thin bony rays, including most modern fish species

bony operculum

a hard, bony flap that covers and protects the gills in bony fish (teleosts) and helps pump water over the gills

ganoine

a hard, enamel-like substance that covers the scales, skull, and fin rays of certain bony fishes, especially in gars and other primitive fish

teleostei

a large infraclass of bony fish (Actinopterygii) characterized by movable jaws, homocercal tails, and bony opercula, comprising most modern fish species

homocercal tail

a type of fish tail where the upper and lower lobes are roughly equal, seen in most modern bony fish, providing efficient forward propulsion

monobasic fin

a fin supported by a single basal bone from which the fin rays extend, common in primitive bony fish

intracranial joint

a flexible joint within the skull of some fish (like sharks) that allows movement between the front and back parts of the cranium, increasing jaw mobility

coelacanths

ancient lobe-finned fish (Sarcopterygii) once thought extinct, with fleshy paired fins and a distinctive tail, considered living fossils

chiridium

a muscular, jointed limb of a tetrapod with a skeletal structure of one upper bone, two lower bones, and digits (fingers or toes)

sacral vertebrae

the vertebrae in the lower spine that are fused to form the sacrum, connecting the spine to the pelvis

lissamphibia

the clade of modern amphibians, including frogs, salamanders, and caecilians, characterized by smooth skin, permeable to water, and a life cycle that often includes an aquatic larval stage

amniotic egg (cleidoic egg)

an egg with a protective shell and specialized membranes (amnion, chorion, yolk sac, allantois) that allow the embryo to develop on land

sauropsida

"lizard faces", major clade of amniote vertebrates comprising all living reptiles (lizards, snakes, turtles, crocodiles), birds, and their extinct ancestors (e.g., dinosaurs, pterosaurs) distinguished by specialized skull structures, scaly skin, and generally laying amniotic eggs

synapsida

a clade of amniotes that includes mammals and their extinct relatives, characterized by a single temporal fenestra (opening) in the skull behind each eye

lepidosauria

a group of reptiles including lizards, snakes, and tuataras, characterized by overlapping scales and a movable quadrate bone in the skull

archosauria

group of reptiles that includes crocodiles, birds, and extinct dinosaurs, characterized by antorbital fenestrae (skull openings in front of the eyes) and socketed teeth

transverse cloacal slit

a horizontal opening of the cloaca in some vertebrates (like amphibians and reptiles) through which excretory and reproductive products are expelled

autotomy

the ability of an animal to deliberately shed a body part, such as a tail or limb, usually as a defense mechanism to escape predators

carapace

the protective top shell of turtles or crustaceans

plastron

the bottom shell of a turtle

crocodilia

an order of large, predatory reptiles including crocodiles, alligators, caimans, and gharials, characterized by elongated snouts, strong tails, and a semi-aquatic lifestyle

Pterosauria

an extinct group of flying reptiles from the Mesozoic Era, characterized by wings formed from a membrane stretched along an elongated fourth finger

Ornithischia

a major group of herbivorous dinosaurs characterized by a “bird-hipped” pelvic structure, including stegosaurs, ankylosaurs, and ceratopsians

Saurischia

a major group of dinosaurs characterized by a “lizard-hipped” pelvic structure, including theropods (like T. rex) and sauropodomorphs (like Brachiosaurus)

feathers

specialized epidermal structures in birds (and some dinosaurs) made of keratin, used for flight, insulation, and display

therapsids

mammal-like reptiles that lived during the Permian and Triassic periods, ancestral to mammals, characterized by differentiated teeth, a more upright posture, and enlarged temporal fenestrae

diphyodont

animals that develop two successive sets of teeth: a primary (milk) set and a permanent set

ontogeny

the development of an individual organism from fertilization to adult form

embryogenesis

the process by which a fertilized egg develops into an embryo, involving cell division, differentiation, and tissue formation