Ch.1 & Ch.2 Comparative Vertebrate Anatomy

Comprehensive vocabulary flashcards covering basic principles of comparative vertebrate anatomy, homeostasis, structural relationships, embryonic development patterns, and chordate origins.

Anatomy

The science of body structures & the relationships among them.

Dissection

The careful cutting apart of body structures to study their relationships.

Physiology

The science of body functions and how body parts work.

Homeostasis

The maintenance of relatively stable internal conditions.

Controlled condition

A monitored body condition maintained within homeostatic limits, such as blood pressure.

Stimulus

A disruption that changes a controlled condition.

Receptors

Body structures that monitor changes in a controlled condition and send nerve impulses or chemical signals as input to a control center.

Control center

A body system component that processes sensory information, 'makes a decision,' & directs the response.

Effectors

Body organs or tissues that carry out the final corrective action to restore homeostasis.

Feedback system (feedback loop)

A cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored, reevaluated, etc.

Negative feedback system

A homeostatic control mechanism that reverses a change in a controlled condition.

Positive feedback system

A feedback system that strengthens or reinforces a change in a controlled condition.

Blood pressure (BP)

The force exerted by blood as it presses against the walls of blood vessels.

Thermoregulation

Homeostatic regulation of body temperature through sweating & adjustment of blood flow in the dermis (the deeper layer of skin).

Morphology

The study of anatomical structure in relation to function and evolution.

Comparative morphology

The comparative study of anatomical structures among different organisms.

Homology

Features in two or more organisms derived from common ancestors; recognizes similarity based upon common origin.

Analogy

Features of two or more organisms that perform a similar function; similarity based upon common function regardless of ancestry.

Homoplasy (Homoplastic structures)

Features in two or more organisms that look alike and are similar in appearance, which may or may NOT be homologous or analogous.

Symmetry

Describes the way in which an animal's body meets the surrounding environment.

Radial symmetry

A body plan arranged around a central axis such that any plane passing through the center divides the body into equal or mirrored halves.

Bilateral symmetry

A body plan in which right & left halves are mirror images of each other.

Planes

Imaginary flat surfaces that pass through body parts.

Segmentation (metamerism)

The process that divides a body or structure into duplicated or repeating sections.

Segment (metamere)

Each repeated section in a segmented body structure.

Function

The action or property of a part as it works in an organism.

Biological role (role)

How a part is used in the environment during the course of the organism's life history.

Phylogeny

The development of evolutionary change within a related group of organisms.

Dendrogram

A branching diagram that represents the evolutionary relationships or history of a group of organisms.

Systematics (systematic biology)

The study of the diversity of life for the purpose of understanding the evolutionary relationships between species.

Natural taxon

A group of organisms that exist in nature as a result of evolutionary events.

Protostomes

A lineage of bilaterian animals characterized by the blastopore developing into the mouth, spiral cleavage, schizocoelic coelom, and an ectodermal skeleton.

Deuterostomes

A lineage of bilaterian animals characterized by the blastopore developing into the anus, radial cleavage, enterocoelic coelom, and a mesodermal skeleton.

Gastrulation

The embryonic process in which the blastula invaginates and grows inward to form tissue layers and the primitive gut.

Blastopore

The opening into the indentation formed during gastrulation.

Ectoderm

The outer germ layer of an embryo.

Endoderm

The inside germ layer of an embryo that forms the lining of the gut.

Mesoderm

The middle germ layer located between the ectoderm & endoderm.

Spiral cleavage

An embryonic cleavage pattern that forms when dividing cells of the embryo are offset from each other.

Schizocoelom

A body cavity (coelom) originating from a splitting of solid masses of mesoderm.

Enterocoelom

A body cavity formed within outpocketings or outpouchings of the mesoderm/primitive gut.

Notochord

A long axial rod that develops from the mesoderm in all chordates, providing longitudinal stiffness and support.

Pharyngeal slits

Openings in the pharynx wall that allow water entering the mouth to exit the body, utilized for filter feeding and/or respiration.

Atrium

A chamber that surrounds the pharynx in suspension-feeding chordates.

Atriopore

The excurrent opening of the atrium through which water exits the body.

Endostyle

A glandular groove in the floor of the pharynx involved in filter feeding that binds iodine from the environment, homologous to the thyroid gland.

Thyroid gland

An endocrine gland that produces, stores, & releases 2 thyroid hormones, homologous to the endostyle.

Dorsal hollow nerve cord

A fluid-filled tube of nervous tissue positioned dorsal to the digestive tract and notochord in chordates.

Neurocoel

The fluid-filled central canal contained within the dorsal hollow nerve cord.

Postanal tail

A posterior elongation of the body extending beyond the anus, serving as part of the locomotor apparatus.

Myomeres

Blocks of striated (striped) muscle arranged sequentially along the body & tail as part of the outer body wall.

Prechordate

An ancestral or early deuterostome form (such as hemichordates) that shares some features of the fundamental chordate body plan.

Protochordates

An informal group of invertebrate deuterostomes comprising Hemichordata, Cephalochordata, and Urochordata.

Pelagic

Organisms that live in open water between the surface & the bottom.

Benthic

Organisms that live on or within a bottom substrate.

Sessile

Organisms that are permanently attached to a bottom substrate.

Solitary

Organisms that live alone.

Colonial

Organisms that live together with others in groups.

Proboscis

The anterior muscular probing organ of acorn worms (Enteropneusta) used in burrowing and feeding.

Stigmata

Smaller openings produced when pharyngeal slits in the pharyngeal wall enlarge, increase in number, & subdivide in ascidians/tunicates.

Tunic

The flexible or tough outer protective covering secreted by subphylum Urochordata.

Gland

A single cell or a group of epithelial cells adapted for secretion.