Lecture 2 - What is Paleobiology

These flashcards cover the major themes, terminology, examples, and evolutionary patterns discussed in the lecture notes on fossils, macroevolution, and deep-time biodiversity.

What provides the only direct record of the history of life on Earth?

Fossils

What type of fossil preserves the actual remains of an organism’s body?

Body fossils

What type of fossil records evidence of an organism’s activity (e.g., footprints, burrows)?

Trace fossils

Name a famous terrestrial vertebrate dinosaur often found as a fossil in Late Cretaceous rocks.

Triceratops prorsus

Which unusual Cambrian organism, once reconstructed upside-down, is considered "bizarre" in the fossil record?

Hallucigenia

Approximately what size scale do microfossils occupy?

From ~100 µm to 1 mm

What two broad categories of information can fossils reveal besides anatomy?

Chemical interactions (e.g., paleotemperatures) and biological interactions (e.g., predator-prey evidence)

Evenly spaced puncture holes in a Placenticeras shell converge to suggest the attack of what marine predator?

A mosasaur

How are sedimentary rocks related to fossils?

Sediments accumulate over time, lithify into rocks, and record fossils of organisms that lived during deposition.

List the three major eras of the Phanerozoic Eon in order from oldest to youngest.

Paleozoic, Mesozoic, Cenozoic

What living animals are scientifically recognized as modern dinosaurs?

Birds

Name the two major dinosaur clades distinguished by hip structure.

Ornithischia and Saurischia

What large-scale evolutionary discipline relies heavily on fossils to study patterns over deep time?

Macroevolution

Why are studies of population genetics alone insufficient to explain long-term evolutionary patterns?

Because many patterns (e.g., mass extinctions, taxonomic turnover) are only evident in the deep-time perspective of the fossil record.

On average, how long do species persist in the fossil record before going extinct?

Roughly 1–25 million years

What term describes the continual replacement of higher taxonomic groups (genera, families, orders) through geological time?

Taxonomic turnover

Fossil distributions of Lystrosaurus, Cynognathus, Mesosaurus, and Glossopteris across southern continents support which geologic theory?

Continental drift (the former supercontinent Gondwana/Pangaea)

Around how many million years before present did the Triassic paleocontinent configuration exist?

Approximately 250 million years ago

What graph pattern in the fossil record shows sudden increases in the rate at which new taxa appear?

"Explosive" diversification events (e.g., the Cambrian Explosion)

List five major mass-extinction events identified from global fossil data.

Late Ordovician, Late Devonian, Permian–Triassic, Late Triassic, Cretaceous–Paleogene (K–Pg)

Which Phanerozoic period is nicknamed the "Age of Reptiles"?

The Mesozoic Era

During what period did archosaurs diversify while mammal-like reptiles declined, as shown by fossil turnover charts?

Late Triassic to Jurassic

What kind of fossil evidence can geochemists use to estimate ancient seawater temperatures?

Chemical signatures (e.g., oxygen-isotope ratios) within fossil shells

Give one reason organisms appear well-adapted yet not perfectly adapted to their environments, as inferred from fossil study.

Adaptations are limited by historical constraints and trade-offs revealed through evolutionary history.

Which extinction event marks the boundary between the Mesozoic and Cenozoic eras?

The Cretaceous–Paleogene (K–Pg) extinction

What does a high proportion of mammalian orders appearing after 65 Ma illustrate about evolutionary patterns?

Post-extinction explosive diversification (radiation) of mammals

How does the fossil record help predict the impact of future climate change on biodiversity?

By providing historical analogs of past climate shifts and their biological consequences, informing better decision-making.

What fossil evidence shows predation strategies beyond tooth marks on bone?

Regular, converging puncture holes on cephalopod shells indicating attack patterns

Why are birds placed within the clade Theropoda on dinosaur family trees?

Phylogenetic analyses of skeletal features show birds share a more recent common ancestor with theropod dinosaurs than with any other group.

Which pair of developmental pathways separates the two great triploblastic animal superclades recognized in the fossil record?

Protostomes (mouth develops first) versus Deuterostomes (anus develops first)