Week 1 - Vert Evolution, Systematics, Characteristics

Systematics

scientific study of kinds and diversity of organisms + evolutionary relationships

Taxonomy

providing names for groups of organisms, establishing rules for how they are named

Chordate Characteristics

notochord, dorsal hollow nerve cord, post anal tail, pharyngeal slits

Speciation

formation of new species

Phylogenetics

connecting species with a tree, evolutionary relationships

Science

testing of theories, use testable and falsifiable hypotheses, collection of facts

Binomial nomenclature

two part names to classify species, Linneaus

Evolution

change of traits in populations over time

endoskeleton

living internal skeleton

paedomorphosis

larvae keeping traits into adulthood

allopatric speciation

formation of new species because of geographic barriers

sympatric speciation

formation of new species in the same place

Founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

Natural selection

based off of fitness of traits, not random, "survival of the good enough"

ecological segregation

Species live in the same area, but segregate relative to specific habitat types

homologous traits

characteristics derived from a common ancestor

Taxa

Groups of organisms used in classification.

gnathastomata

jawed fishes

myxiniformes

hagfish, eel-like

petromyzontiformes

lampreys, extant, cartilage skin, ~40spp

agnathostomes

jawless fish (hagfish/lampreys)

osteognathostomes

extinct, armor, no paired fins

chondrichthyes

cartilaginous fish: sharks, rays, skates, two sets of paired fins, no swim bladder, heterocercal tail

placodermi

plate-skinned fish, extinct, jaws w teeth, pectoral fins, heterocercal tail, no swim bladder

acanthodii

extinct, jaws w teeth, heterocercal tail, multiple sets of paired fins w spines/spikes

osteichthyes

bony fish, largest group of verts, skeleton of bone, gas bladder, thin overlapping scales

actinopterygii

ray-finned fishes, two subgroups

chondrostei

primitive bony fish, mostly cartilage skeleton (secondary bone loss), lacks scales, extant, sturgeon

Bergmann's Rule

endotherms tend to be larger in colder climates

Allen's Rule

extremities of endotherms vary inversely with body size

Gloger's Rule

endotherms living in arid regions tend to be lighter in coloration

Devonian Era

age of fishes

Neopterygii

modern bony fish, most species of fish (~32,500)

Sarcopterygii

lobe finned fishes, precursor to tetrapods

Actinistia

coelacanths, living fossil

Dipnoi

lungfish, double breathers (lungs and gills), closest living relative to tetrapods

Rhipdistians

extinct, double breathers, ancestral precursors to tetrapods (transitional fish)