LBYBIO3 LE1

Vocabulary flashcards covering key terms from the lecture notes on comparative human anatomy, including vertebrate anatomy, chordate features, vertebrate groups, evolution, taxonomy, and anatomical structures.

Comparative Anatomy

The study of similarities and differences in the anatomy of different species to understand how they changed over time to survive better, starting from shared ancestors.

Phylum Chordata

Distinguished by the presence of a notochord, dorsal hollow nerve cord, pharyngeal slits, a post-anal tail, and endostyle.

Subphylum Cephalochordata

Small, filter-feeding organisms with a fish-like body that retain the notochord and nerve cord throughout life, and lack a vertebral column.

Subphylum Urochordata/Tunicata

Sac-like, soft-bodied, filter-feeding organisms with a pharyngeal basket, where the notochord and nerve cord are present only in the larval stage, and lack a vertebral column.

Subphylum Vertebrata

Highly varied organisms with complex body systems. Notochord present in embryo only (becomes vertebrae), nerve cord develops into brain and spinal cord; has a vertebral column/backbone.

Vertebrates

Animals with a backbone or spinal column, also called vertebrae.

Fishes

Aquatic vertebrates with gills, fins, and scales; the first vertebrates to appear in the evolutionary timeline.

Ectotherms

Animals whose body temperature depends on the external environment (cold-blooded).

Endotherms

Animals who maintain a constant body temperature (warm-blooded).

Agnatha

Jawless fishes with a circular, toothed mouth and a cartilaginous skeleton.

Chondrichthyes

Cartilaginous fishes with a cartilaginous endoskeleton.

Osteichthyes

Bony fishes that possess a bony endoskeleton.

Amphibians

Vertebrates that exploit both aquatic and terrestrial habitats, typically with thin, moist skin, and lay eggs in water.

Reptiles

Vertebrates fully adapted to life on land with epidermal scales, breathe with lungs, and lay shelled eggs on land.

Birds

Vertebrates with feathers, wings, beaks, and lightweight skeletons adapted for flight; they also lay hard-shelled eggs and are endotherms.

Mammals

Vertebrates that feed their young with milk from mammary glands, have hair or fur, and are endotherms.

Evolution

The change in the characteristics of a species over several generations, relying on natural selection.

Natural Selection

The process where individuals with more useful traits survive better and produce more progeny than individuals with less-favorable traits.

Divergent Evolution

Occurs when groups from the same common ancestor split into two groups by a geographic barrier, causing each group to develop different traits.

Convergent Evolution

Occurs when organisms that aren't closely related evolve similar traits as they both adapt to similar environments.

Coevolution

Occurs when two or more species reciprocally affect each other's evolution through the process of natural selection.

Phylogeny

The relationship between all the organisms on Earth that have descended from a common ancestor.

Taxonomy

The science of naming, describing, and classifying organisms.

Binomial Nomenclature

A system adopted by Carolus Linnaeus to assign a unique, two-part scientific name derived from Latin or Greek to each kind of organism.

Monophyletic group

Includes the most recent common ancestor of a group of organisms, and all of its descendants (ancestor + all descendants)

Polyphyletic group

Does not include the common ancestor of all members of the taxon (no ancestor)

Paraphyletic group

Includes the most recent common ancestor of a group of organisms, but NOT all of its descendants (ancestor + not all descendants)

Homologous Structures

Similar physical features in organisms that share a common ancestor, but the features serve completely DIFFERENT functions.

Analogous Structures

Features of different species that are SIMILAR in function but not necessarily in structure and do not derive from a common ancestral feature.

Placoid scales

Tough, tooth-like scales found in cartilaginous fishes like sharks, composed of dentine and enamel and reduces drag while smoothing water flow.

Cycloid scale

Thin, round, smooth-edged scales common in bony fish, with growth rings visible.

Ctenoid scale

Thin, rough-edged scales found in advanced bony fish with cteni, small tooth-like projections along the posterior edge.

Ganoid scale

Thick, bony, and armor-like scales with a shiny enamel-like surface, found in primitive fish.

Nictitating membrane

A transparent or translucent third eyelid in toads and crocodiles that protects and moistens the eye.

Scales (fish)

Dermal scales come from the inner skin layer (dermis) and are often mineralized.

Scales (reptiles, birds, mammals)

Epidermal scales come from the outer skin layer (epidermis) and are made of keratin.