ECCB 311 Conway Lecture Exam 1

Ichthyology

Study of fish. Long history but naming of fishes really kicked off in 1758

Aristotle

Gave the earliest "taxonomic" classification of plants and animals. Animals were grouped by complexity, and although it was flawed by today's standards it was pretty good for the time period and even recognized differences between marine mammals and fishes

Carl Linnaeus

Father of modern taxonomy. Named a lot of fish and is credited with coming up with the binomial nomenclature we still use today

Peter Artedi

"Father of Ichthyology". Thought that cetaceans were related to fish (news flash, they're not). Died under suspicious circumstances

Eschmeyer

Created the very thorough Catalog of Fishes

Available name

Any scientific name for a specimen that has already been described

Valid name

the oldest available name (first published correctly)

Rule of priority

Taxonomic law stating once a species has officially
been given a binomial name, the name cannot
be changed.

Senior synonym

the first of the synonyms to be published. According to rule of priority is the valid name

Junior Synonym

A scientific name that has been created for a specimen that has already been described

Homonym

Same name for different species. Was common when scientific information was not easily accessible to taxonomists around the world

International Commission on Zoological Nomenclature (ICZN)

acts as adviser and arbiter for the zoological community by generating and disseminating information on the correct use of the scientific names of animals

Reasons for synonyms

Lack of access to specimens in varying life stages, lack of access to published scientific information, phenotypic variations within a species, etc

Synapomorphy

shared derived trait

Apomorphy

derived trait

Plesiomorphy

ancestral trait

Symplesiomorphy

shared ancestral trait

rule of parsimony

given multiple plausible interpretations of a phylogenetic tree, we should accept the simpler

Willi Hennig

Popularized the idea of phylogenetic systematics (cladistics)

Node (on a cladogram)

A point where a branch splits off from the rest of the cladogram

Phenotypic classification

Classifying on a phylogenetic tree visibly observable characteristics of animals in phylogenetics. Is cheap and can be done with specimens in a wide variety of conditions, but there are limited characteristics that can be identified with the naked eye, and some things are subjective

Genotypic classification

Classifying on a phylogenetic tree based on genetic information. Can be quick and thorough but is often expensive and can only be done with fresh, extant specimens

Molecular data

Not always a silver bullet. Relationships of some groups remain difficult to untangle even using molecular data to study genotypes

Problem areas in Ichthyology

Basal relationships, acanthodians, and certain groups of teleosts

Acanthodians

Group of jawed fishes, characterized by large spines in their fins. Their relationship to other fishes isn't quite agreed upon

Basal groups

Relationship of primitive groups of fishes (lampreys, hagfish and extinct primitive fish) to each other and derived fish groups is not agreed upon

Anadromous

Life cycle in which fish are born in fresh water, migrate to salt water as adults, and then go back to fresh water in order to reproduce. Examples: Salmon, Atlantic Sturgeon

Catadromous

Life cycle in which creatures are born in salt water, migrate to fresh water as adults, and then go back to salt water in order to reproduce. Examples: American/European Eel, striped mullet

Diadromous

Migrate between fresh and salt water for spawning purposes. Categorized into anadromous, catadromous, and amphidromous

Myers freshwater fish classification

Splits freshwater fish into primary and secondary freshwater fish

primary freshwater fish

Groups restricted to freshwater with little or no tolerance for saltwater. Example: tetras, channel catfish

secondary freshwater fish

Groups usually restricted to freshwater but with strong tolerance for saltwater. Example: alligator gar, cichlids

Amphidromous

Fish that migrate between saltwater and freshwater, but not for breeding purposes. Example: bull shark

Freshwater fish diversity

Far higher than saltwater fish diversity, probably due to geographical differences which have caused genetic bottlenecks and genetic drift over time

Peripheral species

Non-migratory species of otherwise marine groups that complete their entire lifecycle in freshwater. Around 30 marine families have at least one peripheral freshwater member

allopatric speciation

The formation of new species in populations that are geographically isolated from one another. This is a big factor in the increased diversity of freshwater fish compared to saltwater fish diversity

sympatric speciation

The formation of new species in populations without a geographic barrier. This can happen because in a resource-abundant area more niches arise and more species come about to fill those niches

Geminate species pairs

A concept introduced by David S. Jordan (apparently we need to know that name). Used to explain how very similar species occur across a geographic barrier, and can be a hint towards geological activity in the area

Biogeography

Study of past and present distribution of organisms

Homology

Similarity in characteristics resulting from a shared ancestry

Convergence

A similar character separately appearing in two distant linneages

Fin folds

Type of paired fins that have a broad base and are seen mostly in chondrichthys and basal lineages of fish (eg. lamprey)

Ceratotrichia

Stiff, unsegmented, and unbranched rays of chondricthyes

Actinotrichia

Keratinized tips of some lepidotrichia

Lepidotrichia

Bony, bilaterally paired, segmented fin rays found in bony fishes. During development they form from fin folds

soft lepidotrichia

Found in all fins

spinous lepidotrichia

Only found in dorsal, anal, and pelvic fins