Zoology: Biological Classification and Animal Morphology

Comprehensive vocabulary flashcards covering the history of taxonomy, classification hierarchies, binomial nomenclature, animal symmetry, germ layers, anatomical structures, and directional terminology.

Taxonomy

The science of biological classification that produces a formal system for naming and classifying species to reflect an order.

Aristotle

Greek philosopher (384-322 B.C.) who began taxonomy by separating living things into plants (herbs, shrubs, trees) and animals (classified by size, habitat, and movement).

John Ray

English naturalist (1627-1705) who outlined the idea of a species, marking the beginning of modern classification.

Carolus Linnaeus

Swedish botanist (1707-1778) who developed a classification scheme subdividing plants and animals into classes, orders, genera, and species based on physical traits.

Ernst Haeckel

German zoologist (1834-1919) who in 1866 proposed creating a third kingdom called Protists for unicellular organisms.

Protists

A kingdom proposed by Ernst Haeckel in 1866 to contain minute, primarily one-celled organisms.

R.H. Whittaker

American biologist (1924-1980) who in 1959 proposed a universally accepted five-kingdom system consisting of Monera, Protista, Fungi, Plantae, and Animalia.

Monera

A kingdom in Whittaker's five-kingdom system that included all prokaryotes (bacteria), which was later split into Eubacteria and Archaebacteria.

Archaebacteria

Ancient prokaryotes that often live in extreme environments, such as very hot or salty places like the Grand Prismatic Spring in Yellowstone National Park.

Eubacteria

Kingdom containing true bacteria, formed after the split of kingdom Monera.

Taxonomic Relationship Criteria

The five factors used to determine relationships among species: structural similarities, breeding behavior, geographical distribution, chromosome comparisons, and biochemistry.

Hierarchical System

A scheme that arranges organisms into a series of ranks (taxa) where broader taxa contain more general characteristics and a greater number of species.

Seven Major Taxa

The main categories of biological classification arranged from broadest to most specific: Kingdom, Phylum, Class, Order, Family, Genus, Species.

Division

The taxon category used by plant taxonomists in place of Phylum.

Binomial Nomenclature

Linnaeus' system for naming organisms using a two-word Latinized name written in italics or underlined, where the first word is a noun (genus) and the second is an adjective (species).

Species

A group of organisms that can interbreed and produce fertile offspring in nature.

6 Kingdom System

The modern classification system consisting of Animal, Plantae, Fungus, Protista, Eubacteria, and Archaebacteria.

Animal Morphology

The study of the form and physical structure of animal bodies.

Physiology

The study of biological function, which is always linked with morphology.

Asymmetry

A body organization with no definite or regular shape of body parts, as seen in amoebas and many sponges.

Spherical Symmetry

A round body form that meets the environment equally on all sides, best suited for floating or rolling (e.g., Volvox).

Radial Symmetry

Body parts arranged around a central axis such that any plane passing through the central axis divides the body into mirror-image halves (e.g., starfish, sand dollars, jellyfish).

Bilateral Symmetry

Body parts divided into equal mirror-image halves by a single plane of symmetry (e.g., mammals, flatworms, fish).

Germ Layers

Embryonic layers that give rise to specific body structures during embryonic development in animals.

Ectoderm

The outer germ layer that gives rise to the epidermis and the nervous system.

Endoderm

The inner germ layer that gives rise to the lining of the digestive system and respiratory system.

Mesoderm

The middle germ layer that gives rise to muscles, connective tissues, bone, and the circulatory system.

Diploblastic

Refers to organisms derived from two germ layers: ectoderm and endoderm (e.g., Hydra, jellyfish).

Triploblastic

Refers to organisms derived from three germ layers: ectoderm, endoderm, and mesoderm (e.g., insects, birds, mammals).

Incomplete Digestive System

A digestive system featuring a single opening (mouth) leading to a sac-like gut called a gastrovascular cavity (e.g., Hydra, Planaria).

Complete Digestive System

A digestive system featuring separate openings for the mouth and anus (e.g., insects, crayfish, humans).

Endoskeleton

An internal skeleton structure found in vertebrates.

Exoskeleton

An external skeleton structure found in invertebrates.

Segmentation

The serial repetition of body parts into distinct segments.

Metamere

An individual segment in a segmented body arrangement, also called a somite.

Monoecious

Having both male and female reproductive organs within a single organism; also known as hermaphroditic (e.g., earthworm).

Dioecious

Having separate male and female sexes in different individual organisms (e.g., birds and bees).

Poikilothermic

Cold-blooded (ectothermic) animals whose body temperatures fluctuate with the environment.

Homoiothermic

Warm-blooded animals (birds and mammals) that regulate and maintain a constant body temperature.

Cephalization

The concentration of nervous and sensory structures to form a head at the anterior end of an organism.

Anterior

Anatomical directional term meaning closer to the top of the head or front end.

Posterior

Anatomical directional term meaning closer to the rear or butt end.

Dorsal

Anatomical directional term meaning towards or on the back.

Ventral

Anatomical directional term meaning towards or on the front/belly.

Medial

Anatomical directional term meaning closer to the midline of the body.

Lateral

Anatomical directional term meaning farther from the midline of the body.

Distal

Anatomical directional term meaning farther from the point of attachment.

Proximal

Anatomical directional term meaning near or closer to the point of attachment.

Frontal Plane

An anatomical plane that divides the body into front and back portions.

Sagittal Plane

An anatomical plane that divides the body into left and right portions.

Transverse Plane

An anatomical plane that divides the body into anterior and posterior portions.

Pectoral

Anatomical term having to do with or relating to the shoulders.

Pelvic

Anatomical term having to do with or relating to the legs.