Term List (Test 1) - Fossils Flashcards
acritarch
catchall group of various small microfossils that represent the pelagically dispensed spore cases of benthic algae
analog
a representation of an object that resembles the original
apomorphy
a new or derived characteristic that has evolved from an ancestral form
Archeocyatha
taxon of extinct, sessile, reef-building marine sponges that lived during the Cambrian period
bioturbation
a process by which living organisms move and change soil sediment
biozone
a layer of rock or sediment that contains fossils from a specific group of organisms that lived during a specific time period
brachiopoda
a phylum that is comprised of animals with two hard valves (shells) connected by a hinge
Bryozoa
a phylum of simple, aquatic invertebrate animals
Cambrian fauna
incredibly diverse and marked the first appearance of many complex life forms. Trilobites (group of armoured invertebrates) are the most popular example
choanoflagellate
a group of free-living unicellular and colonial flagellate eukaryotes
carbonization
a process that converts organic material into carbon-rich compounds through heat and a lack of Oxygen
clade
a group of organisms believed to have evolved from a common ancestor, according to the principles of cladistics
convergence
the tendency of unrelated animals and plants to evolve superficially similar characteristics under similar environmental conditions
cnidaria
phylum of aquatic invertebrate animals that comprise of the coelenterates
diploblast
the presence of two germ layers. ex. cnidarians
divergence
the process by which related species develop different traits over time which can lead to new species
ecophenotypic variation
the variation in an organisms phenotype that is caused by its environment
Ediacaran fauna
unique assemblage of soft-bodied organisms preserved as fossil impressions in sandstone. represent an important development in the evolution of life due to immediate predation of life forms in the Cambrian period
eukaryote
an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus
Elvis taxa
a taxon that has been misidentified as having re-emerged in the fossil record after a period of presumed extinction, but is not actually a descendant of the original taxon, instead having developed a similar morphology by convergent evolution.
endosymbiosis
a symbiotic relationship where one organism lives inside another
evolutionary radiation
a rapid increase in the diversity of a group of organisms, or clade
eumetazoan
a proposed diploblastic basal animal clade as a sister group of Porifera
exotic terrane
a piece of the Earth’s crust that has been moved from its original location and joined with another landmass