Form, Function & Evolution Of Vertebrates

These flashcards cover key vocabulary terms and concepts from the lecture on the form, function, and evolution of vertebrates.

Vertebrates

Diverse group of animals that have a backbone.

Cladistics

A method of classifying species based on common ancestry.

Monophyletic

A group descended from a common evolutionary ancestor.

Paraphyletic

A group that includes a common ancestor but not all its descendants.

Polyphyletic

A group derived from more than one common evolutionary ancestor.

Derived characters

Traits that are different from the ancestral condition.

Apomorphies

Characters that are different from the ancestral condition.

Synapomorphies

Shared derived characters among a group.

Plesiomorphies

Characters that are similar to the ancestor.

Symplesiomorphies

Shared ancestral characters.

Parsimony

The principle that prefers the simplest explanation; fewer changes are favored.

Polarity

The direction of evolutionary change of characters.

Outgroups

Groups used as a point of comparison in phylogenetic analysis.

Ingroups

The group being studied in phylogenetics.

Amniotes

Vertebrates with embryonically derived membranes.

Non-Amniotes

Vertebrates without embryonically derived membranes.

Myxinoidea

Class of jawless fish, known as hagfish.

Petromyzontidae

Class of jawless fish, known as lampreys.

Chondrichthyes

Class of fish characterized by cartilaginous skeletons, including sharks and rays.

Osteichthyes

Class of bony fish.

Actinopterygians

Ray-finned fish, part of Osteichthyes.

Sarcopterygians

Lobe-finned fish closely related to tetrapods.

Tetrapods

Vertebrates with four limbs, including amphibians, reptiles, birds, and mammals.

Anura

Order of amphibians that includes frogs and toads.

Urodela

Order of amphibians that includes salamanders.

Gymnophiona

Order of amphibians commonly known as caecilians.

Testudinia

Order that includes turtles, tortoises, and terrapins.

Lepidosauria

Group that includes lizards and snakes.

Archosauria

Group that includes crocodiles and birds.

Aves

Class of animals that includes birds.

Synapsids

Class of animals that includes mammals.

Monotremes

Egg-laying mammals, such as the platypus.

Marsupials

Mammals that give birth to live young that then mature in pouches.

Placentals

Mammals that give birth to fully developed young after a long gestation.

Chordata

The phylum that includes all vertebrates and some closely related invertebrates.

Ectoderm

The outermost germ layer that develops into the skin and nervous system.

Endoderm

The innermost germ layer that forms the lining of the digestive tract.

Mesoderm

The middle germ layer that forms muscles, bones, and the circulatory system.

Gastrulation

The process that forms germ layers in the embryo.

Deuterostome

An organism whose mouth is formed from the second opening of the embryo.

Autonomous specification

When cell fate is determined without input from neighboring cells.

Conditional specification

When cell fate is determined by interactions with neighboring cells.

Notochord

A solid midline bar of tissue that provides support in chordates.

Dorsal hollow nerve tube

The neural structure that develops into the central nervous system.

Pharyngeal slits

Anatomical structures that are used for feeding in non-vertebrate chordates.

Endostyle

A glandular tissue important in feeding, present in some chordates.

Post-anal tail

An extension of the body beyond the anus, present in chordates.

Urochordates

Marine invertebrate chordates also known as tunicates.

Cephalochordates

Small, fish-like chordates, such as lancelets.

Lamprey

A jawless fish that is known for being parasitic.

Hagfish

A jawless fish known for producing slime.

Ostracoderms

Early jawless fish with bony armored skin.

Conodonts

Extinct jawless vertebrates known for their tooth-like structures.

Gnathostome

Jawed vertebrates, evolved from earlier jawless forms.

Chondrichthyes

Class of fish characterized by their cartilaginous skeletons.

Osteichthyes

Class of bony fish that are more diverse than chondrichthyans.

Neural crest cells

Cells that develop into diverse structures in vertebrates, including nerves.

Sympatric speciation

The evolution of new species from a common ancestor while inhabiting the same geographical area.

Allopatric speciation

The evolution of new species due to geographical separation.

Biogeography

The study of the distribution of species over geographical areas.

Phylogenetics

The study of evolutionary relationships among biological entities.

Morphological convergence

The process by which unrelated organisms evolve similar structures.

Adaptive radiation

The diversification of a group of organisms into forms filling different ecological niches.

Homologous structures

Structures that share a common ancestry but may have different functions.

Analogous structures

Structures that have similar functions but do not share a common ancestry.

Extant species

Species that are currently living, as opposed to extinct species.

Fossil record

The history of life as documented by fossils.

Embryonic development

The process of development of an embryo from fertilization to birth.

Paleozoic era

A geologic era that lasted from about 541 to 252 million years ago.

Mesozoic era

The era that lasted from about 252 to 66 million years ago, known as the age of reptiles.

Cenozoic era

The current geological era, beginning 66 million years ago and characterized by the dominance of mammals.

Comparative anatomy

The study of similarities and differences in the anatomy of different species.

Gene duplication

The process by which a gene is copied in the genome.

Hox genes

A group of related genes that control the body plan of an embryo along the anterior-posterior axis.

Neurulation

The process during embryonic development that forms the neural tube.

Myomeres

Segmented muscle blocks that are typical in fish and some other vertebrates.

Hydroxyapatite

A mineral form of calcium apatite, a major component of bone.

Endochondral bone

Bone that develops from a cartilaginous model.

Dermal bone

Bone that forms directly from dermis, without a cartilaginous precursor.

Ossification

The process of bone formation.

Muscular skeleton

The muscular system that supports the body in motion.

Tissue differentiation

The process by which cells become specialized in structure and function.

Ectodermal derivatives

Structures that arise from the ectoderm, such as skin and nerves.

Mesodermal derivatives

Structures that arise from the mesoderm, such as muscle and bone.

Fossilization

The process by which organic materials are preserved in sediment.

Aquatic locomotion

The movement of organisms through water.

Buoyancy adaptations

Physical adaptations that help organisms maintain their position in the water column.

Osmoregulation

The process by which organisms regulate their internal salt and water concentrations.

Predatory adaptations

Features that enhance the ability of organisms to catch prey.

Symbiotic relationships

Interactions between different species that live together in close proximity.

Reproductive strategies

The methods by which species reproduce and raise their young.

Skeletal modifications

Changes in bone structure that allow for new functions or adaptations.