Continental Drift
He proposed the theory of continental drift in 1915, though it wasn't accepted until the 1960s.
Who is Alfred Wegener?
This type of fossil consists of tracks, burrows, or feces rather than the organism's body.
What are trace fossils?
This bias occurs because the Earth's crust is recycled, making older rocks rarer and harder to recover.
What is temporal bias?
This term describes a change within a single evolutionary lineage over time.
What is anagenesis?
This specific fauna, dating from 565–544 MYA, represents soft-bodied organisms that largely don't fit into modern phyla.
What is the Ediacaran fauna?
The Rocky Mountains were created by which type of plate boundary, and how?
Convergent plates that moved towards each other to create mountain ranges.
Compare permineralized fossils to compression fossils in terms of their formation process and the type of biological information they preserve.
Permineralized = mineral deposits within cells; Compression = flattened specimens pressed into surfaces.
Explain how geographic and taxonomic biases work together to create an incomplete record for terrestrial soft-bodied organisms.
Lowlands/marine environments (geographic) and organisms with hard parts (taxonomic) are favored, leaving soft-bodied terrestrial life underrepresented.
Define the concept of a "chronospecies" and explain how it differs from the biological species concept typically used for extant organisms.
Chronospecies are temporally distinct parts of a single lineage with phenotypically different forms. It is a result of anagenesis (gradual, continuous change), while the biological species concept relies on a splitting event.
Describe the environmental conditions of the Proterozoic Eon and how they differ from the subsequent Cambrian Period in terms of life forms.
Proterozoic (2.5 BYA–543 MYA) was mostly prokaryotes/algae; Cambrian (541 MYA+) saw skeletonized animal radiation with more complex morphology.
Contrast the three primary types of plate boundaries based on their movement and provide one example of how these boundaries affect the Earth's crust.
Boundaries are divergent (apart), convergent (together), and transform (sliding).
Evaluate the conditions required to produce "unaltered remains" and explain why these are significantly rarer than other fossil types.
Requires unique preservation (amber, permafrost) to prevent decay or mineralization.
Why are the origins of higher taxa are rarely captured in the fossil record?
Consumption by others, irregular sedimentation, and the need for rocks to solidify/persist/be exposed
If species A and B are morphologically different chronospecies, which event must have occured? How about if A continues to exist, while B splits off from A and creates another species lineage?
Anagenesis/pseudoextinction; Cladogenesis
Analyze the significance of the Burgess Shale in our understanding of the "Cambrian Explosion" and the diversity of skeletonized marine life.
Canadian site preserving the best record of skeletonized marine animals and phyla/classes.
Explain the role of seafloor spreading as the mechanism that validated Wegener's initial observations of continental movement.
Seafloor spreading provided the evidence for drift via plate tectonics.
Describe the physical process of how casts and molds are formed and why they provide external morphology but not internal cellular detail.
External impressions (molds) filled with mineral material (casts). Common with organisms with hard exoskeletons.
Explain the difficulties paleontologists face when interpreting crushed or fragmented fossils, and how this impacts the accuracy of phylogenetic reconstruction.
Fragmented remains make precise anatomical measurements and relationship determinations difficult.
Differentiate between pseudoextinction and real extinction, explaining the evolutionary implications for the lineage in each scenario.
Pseudoextinction = name disappears but descendants remain; Real extinction = total failure to leave descendants.
Name some of the phyla and classes of marine animal fossils that appaered during the Cambrian explosion.
Trilobites, crustaceans, arthropods, worms, chordates, etc.
What evidence was used to support continental drift before the discovery of seafloor spreading?
The presence of similar organisms found in similar strata on different continents.
Discuss how the study of trace fossils provides insights into ancient organisms that body fossils cannot provide.
Behavioral evidence like movement, feeding, or social structures. Ex. burrows, footprints, feces, etc.
Explain why the rarity of older rocks (older than 2.5 BYA) limits our study of the earliest life.
Rocks older than 2.5 BYA are rare because the Earth's crust is recycled. Signs of life from then are unlikely to have survived.
Contrast anagenesis and cladogenesis in terms of their effect on biological diversity and how each process appears in a lineage's fossil record.
Anagenesis is linear change that creates chronospecies; cladogenesis is the splitting of a lineage that creates another distinct species.
What could have caused the Cambrian explosion?
Increasing oxygen levels to promote diversification of species, vacant ecological habitats that needed to be occupied, key innovations to support developing multicellularity, etc.