Paleontology and Dinosauria Lecture Notes

These flashcards cover key principles, dates, and figures related to paleontology, dinosaurs, and significant extinction events.

Superposition

Oldest rocks are found at the bottom of layers.

Original horizontality

Layers of sediment are originally deposited flat.

Lateral continuity

Layers of rock extend sideways in all directions.

Cross-cutting

Geological features that cut through others are younger.

Faunal succession

The predictable order of fossilized organisms in the rock record.

Uniformitarianism

The principle that the present is the key to understanding the past.

Unconformity

A gap or missing time in the geological record.

Fossilization

The process by which organic material is preserved in the rock record.

Dinosauria

Group of reptiles defined by specific skeletal features.

Steno

Pioneer in stratigraphy and anatomy.

Cuvier

Introduced the concept of extinction.

Owen

Coined the term Dinosauria, highlighting upright stance.

Lyell

Promoted the principle of uniformitarianism.

Darwin/Wallace

Developed the theory of natural selection.

Curie

Contributed to the understanding of radioactivity and Earth's age.

Ornithischians

Bird-hipped dinosaurs, primarily herbivores.

Saurischians

Lizard-hipped dinosaurs, includes both Theropods and Sauropods.

Archaeopteryx

A transitional fossil exhibiting traits of both reptiles and birds.

Feathers

Evolved in stages from bristles to down to flight feathers.

Chicxulub impact

Asteroid impact linked to the mass extinction event that ended the dinosaurs.

End-Permian

The greatest mass extinction event, where over 90% of species were lost.

Adaptive radiation

The rapid evolution of diverse species from a common ancestor following a mass extinction.

Superposition

Oldest rocks are found at the bottom of layers.

Original horizontality

Layers of sediment are originally deposited flat.

Lateral continuity

Layers of rock extend sideways in all directions.

Cross-cutting

Geological features that cut through others are younger.

Faunal succession

The predictable order of fossilized organisms in the rock record.

Uniformitarianism

The principle that the present is the key to understanding the past.

Unconformity

A gap or missing time in the geological record.

Fossilization

The process by which organic material is preserved in the rock record.

Dinosauria

Group of reptiles defined by specific skeletal features.

Steno

Pioneer in stratigraphy and anatomy.

Cuvier

Introduced the concept of extinction.

Owen

Coined the term Dinosauria, highlighting upright stance.

Lyell

Promoted the principle of uniformitarianism.

Darwin/Wallace

Developed the theory of natural selection.

Curie

Contributed to the understanding of radioactivity and Earth's age.

Ornithischians

Bird-hipped dinosaurs, primarily herbivores.

Saurischians

Lizard-hipped dinosaurs, includes both Theropods and Sauropods.

Archaeopteryx

A transitional fossil exhibiting traits of both reptiles and birds.

Feathers

Evolved in stages from bristles to down to flight feathers.

Chicxulub impact

The asteroid impact (forming the Chicxulub crater) in the Yucatan Peninsula, evidenced by high iridium levels and shocked quartz globally, is linked to the mass extinction event that ended the non-avian dinosaurs at the Cretaceous-Paleogene boundary.

End-Permian

The greatest mass extinction event, where over 90% of species were lost.

Adaptive radiation

The rapid evolution of diverse species from a common ancestor following a mass extinction.

Kelvin's error

The misconception about Earth's age due to lack of knowledge about radioactive heat, leading to an underestimation of its true age.

Homology

A similarity between organisms (e.g., structures, genes) due to shared ancestry.

Analogy

A similarity between organisms (e.g., structures, functions) due to convergent evolution, not shared ancestry.

Linnaeus

Developed the nested classification system for organisms, which is still in use today.

Pangaea

A supercontinent that began to break apart during the Mesozoic Era, splitting into northern (Laurasia) and southern (Gondwana) landmasses.

Index fossils

Fossils used to define and identify geologic periods, often characteristic of a particular time range (e.g., ammonites).

Bone Wars

A period of intense fossil discovery and rivalry between paleontologists Edward Drinker Cope and Othniel Charles Marsh in the late 19^{th} century.

Hadrosaurus

The genus of the first dinosaur for which a relatively complete skeleton was assembled and mounted (by Joseph Leidy).

Pelycosaurs

An extinct group of synapsids, which are more closely related to mammals than to dinosaurs.

Ichthyosaurs

Marine reptiles (not dinosaurs) known for being fully aquatic and giving live birth.

Pterosaurs

Flying reptiles (not dinosaurs) whose wings were supported by an elongated fourth finger.

Stegosaur plates

The large, bony plates along the back of Stegosaurus, with proposed functions including defense, display, or thermoregulation.

Marginocephalia

A group of ornithischian dinosaurs characterized by skull elaborations, likely used for display or combat.

Sauropod gigantism

The enormous size of Sauropods is attributed to adaptations such as pneumatized (air-filled) bones for lighter skeletons and graviportal (pillar-like) limbs to support their massive weight.

Theropod features

Characteristic features of Theropod dinosaurs include three-fingered hands, bipedal locomotion, and a direct ancestral link to birds.

Evidence for endothermy in dinosaurs

Indicators suggesting that some dinosaurs were warm-blooded (endothermic) include high predator-prey ratios, rapid growth rings in bones, and the presence of feathers.

Evidence for ectothermy in dinosaurs

Indicators suggesting that some dinosaurs were cold-blooded (ectothermic) include smaller nasal passage sizes and gigantothermy (maintaining high body temperature due to large size).

Dinosaur Renaissance

A period beginning in the 1960s that re-evaluated dinosaurs as active, agile, and bird-like animals, partly prompted by discoveries like Deinonychus.

Furcula (wishbone)

The fused clavicles (collarbones) found in birds and some dinosaurs, which is homologous to the clavicles of other vertebrates.

The Big Five mass extinctions

The five major mass extinction events in Earth's history: End-Ordovician, Late Devonian, End-Permian, End-Triassic, and Cretaceous-Paleogene.

End-Triassic mass extinction

A mass extinction event that led to the decline of many large crurotarsans (croc-relatives), allowing dinosaurs to become the dominant terrestrial vertebrates.