Term List #2 - Biol 3p03 Flashcards
Ammonoidea
extinct, coiled-shelled cephalopods . They are more closely related to living octopuses, squid, and cuttlefish than they are to nautiluses
what is the different between ammonoidea and nautiloidea
Ammonoidea has more suture complexity than Nautiloidea which allows them to be stronger, as there is more welding holding the valves together. ammonoidea is also exinct whereas nautiloidea is not
Archeocyatha
‘ancient cups’ is a taxon of extinct, sessile, reef-building marine sponges that lived in warm tropical and subtropical waters during the Cambrian Period
belemnite
an extinct cephalopod mollusk with a bullet-shaped internal shell that is typically found as a fossil in marine deposits of the Jurassic and Cretaceous periods
Bivalvia
Bivalves are aquatic, invertebrate animals that have 2 shells of equal size they can close around themselves. They can be found in salt, fresh, and brackish water.
Cambrian Fauna
the unique assemblage of marine animals that emerged during the Cambrian explosion, a period of rapid diversification of life around 540 million years ago, characterized by the appearance of hard-shelled organisms like trilobites and other invertebrates.
Cephalopoda
meaning “head-foot” in Greek, refers to a class of marine mollusks including octopuses, squid, cuttlefish, and nautilus, characterized by a prominent head, highly developed eyes, and arms or tentacles modified from the primitive molluscan foot.
ceratitic
an extinct genus of ammonite cephalopods. These nektonic carnivores lived in marine habitats in what is now Europe, during the Triassic, from the upper-most Anisian to the lower Ladinian age.
convergence
the tendency of unrelated animals and plants to evolve superficially similar characteristics under similar environmental conditions.
Coleoidea
one of the two subclasses of cephalopods containing all the various taxa popularly thought of as “soft-bodied” or “shell-less”
Cope’s Rule
named after the paleontologist Edward Drinker Cope, describes the evolutionary trend where lineages tend to increase in body size over time.
Court Jester Hypothesis
large-scale evolutionary changes, including speciation and extinction, are primarily driven by abiotic factors like climate change and geological events, rather than biotic interactions
Devonian Nekton Revolution
a period of rapid diversification and expansion of actively swimming (nektonic) animals, particularly fish, during the Devonian Period (roughly 419 to 359 million years ago).
Divergence
the process where a population of an ancestral species evolves into two or more descendant species, becoming increasingly dissimilar in form and structure due to adaptation to different environments or selective pressures.
evolutionary trends
identifiable, long-term patterns of directional change in the overall evolution of a trait within a group of organisms, representing a persistent direction of evolution
functional morphology
the study of the relationship between an organism’s structure (form) and its function, analyzing how anatomical features are adapted to specific behaviors and ecological contexts.
Gastropoda
a large class of mollusks which includes snails, slugs, whelks, and all terrestrial kinds. They have a large muscular foot for movement and (in many kinds) a single asymmetrical spiral shell
giantism
The evolutionary trend in which a species develops significantly larger body sizes compared to its smaller-bodied ancestors, often as an adaptive response to ecological pressures such as predation, resource availability, or environmental conditions.
goniatitic
ammonoid cephalopods that form the order Goniatitida, derived from the more primitive Agoniatitida during the Middle Devonian some 390 million years ago
Great Ordovician Radiation
a period of intense diversification of marine animal life that occurred during the Ordovician period (roughly 485.4 to 443.4 million years ago
HAM
Human and other Animal Morphology”, a field that studies the morphology and anatomy of extinct animals, including humans and their ancestors, through the analysis of fossilized remains.
homology
two or more species having structures of the same embryonic origin
Hox genes
a group of related genes that encode transcription factors. play a major role in determining body plan of an embryo
ichnofossil
a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself. (trace fossil)
Lilliput Effect
the observed trend of smaller body size in faunal elements that survive mass extinction events. a phenomenon coined by Urbanek in 1993.
Lingulidae
a genus of brachiopods within the class Lingulata. Lingula or forms very close in appearance have existed possibly since the Cambrian. Like its relatives, it has two unadorned organo-phosphatic valves and a long fleshy stalk
logarithmic spiral
a type of spiral shape found in the shells of certain fossils, such as ammonites and nautiloids. This spiral follows a mathematical pattern where the distance between the coils increases in a consistent ratio, meaning the shape remains the same as it expands outward. The logarithmic spiral provides structural strength and efficient growth, allowing organisms to grow without changing their overall form.
macroevolution
major evolutionary change. The term applies mainly to the evolution of whole taxonomic groups over long periods of time.
mass extinction
a period of time when many species die out faster than they can be replaced. This event is usually defined as the loss of at least 75% of species in a short geological time, which can be millions of years.
microevolution
evolutionary change within a species or small group of organisms, especially over a short period.
Modern Fauna
a group of marine organisms, characterized by a “Mollusc-rich assemblage,” that emerged after the Mesozoic-Cenozoic radiation and is still in progress, including classes like Gastropoda, Bivalvia, and Osteichthyes.
Nautiloidea
a group of marine cephalopods which originated in the Late Cambrian and are represented today by the living Nautilus and Allonautilus. Fossil nautiloids are diverse and species rich, with over 2,500 recorded species.
ontogeny
ontogeny refers to the developmental history of an organism from its earliest stage (such as an embryo) to its mature form
Paleozoic Fauna
the diverse assemblage of ancient marine and terrestrial life forms that flourished during the Paleozoic Era (roughly 541 to 252 million years ago), characterized by the evolution of invertebrates, early fish, and the colonization of land by plants and animals
paedomorphosis
Having some features of the ancestral juvenile stage, but being an adult (with a mature reproductive system). means “child form”
phyletic gradualism
a model of evolution which theorizes that most speciation is slow, uniform and gradual. When evolution occurs in this mode, it is usually by the steady transformation of a whole species into a new one.
protostome
a Phylum under Kingdom Animalia (animals), they have spiral determinate cleavage, a mouth develops before the anus in embryos, true tissues, and are bilaterally symmetric. protosomia is greek for “first mouth)
pulmonates
are a group of gastropod mollusks that have a specialized lung-like structure for breathing air. They include many land snails, freshwater snails, and some marine species. Pulmonates lack gills and instead use a vascularized mantle cavity as a lung. They are known for their hermaphroditic reproductive system and diverse habitats
punctuated equilibrium
the hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change.
radiation
divergence out from a central point, in particular evolution from an ancestral animal or plant group into a variety of new forms
radula
(in a mollusk) a structure of tiny teeth used for scraping food particles off a surface and drawing them into the mouth.
Red Queen Hypothesis
species (or populations) must continually evolve new adaptations in response to evolutionary changes in other organisms to avoid extinction
Rhynchonellidae
a taxonomic order of articulate brachiopods, characterized by their strongly ribbed, wedge-shaped or nut-like shells, and a short hinge line, with a zigzagged commissure (the line between the two valves)
Rugosa
extinct order of corals that thrived from the Ordovician to the Permian period. They had a distinctive wrinkled or ridged exoskeleton and could be solitary (shaped like a horn) or colonial. Rugose corals had a calcite skeleton and are important index fossils for dating Paleozoic rock layers
rudists
a cone-shaped extinct bivalve mollusk that formed colonies resembling reefs in the Cretaceous period
Scleractinia
an order of corals that first appeared in the Middle Triassic and continue to the present. They have a calcium carbonate skeleton, which contributes to reef-building in modern oceans. Unlike the extinct Rugosa corals, Scleractinians have a different skeletal structure based on aragonite instead of calcite
similarities and differences of scleractinia and rugosa
similarities:
- both are a type of anthrozoan corals
- both can be colonial
differences:
- Rugose has bilateral symmetry, and scleractinia had radial
- Rugose lived in the Paleozoic era, and Scleractinia is from the Triassic era to current
- Rogose is made up of calcite and Scleractinia is aragonite
Stromaroporoidea
an extinct clade of sea sponges common in the fossil record from the Middle Ordovician to the Late Devonian. They can be characterized by their densely layered calcite skeletons lacking spicules
Strophomenidae
an extinct order of articulate brachiopods which lived from the lower Ordovician period to the mid Carboniferous period. Strophomenida is part of the extinct class Strophomenata, and was the largest known order of brachiopods, encompassing over 400 genera
stasis
a period in which a species shows little to no evolutionary change over a long time. This concept is a key part of punctuated equilibrium
Tabulata
an extinct order of colonial corals that lived from the Ordovician to the Permian period. They are named for their horizontal internal plates (tabulae) that divided their skeletal structures. Unlike Rugosa, they rarely had well-developed septa. Tabulate corals were important reef builders in Paleozoic marine environments and went extinct during the Permian-Triassic mass extinction.
