All Review Cards Flashcards
(114 cards)
Darwin’s Mechanisms for Natural Selection
- ) Populations are variable
- ) variants that are successful leave more viable offspring
- ) Change will appear over time
Darwin’s Important Claims
- ) all living things share a common ancestor
2. ) species on Earth evolve from a natural process
Evidence for Evolution (4)
- ) Fossil Record
- ) Classification and biography
- ) Morphology and development
- ) DNA (Genetics)
Main questions debated by early scholars concerning fossils
- ) Are they organic material?
- ) How did they get there?
- ) Did they form in the rock or did the rock form around them?
6 Verifiable Predictions of Evolutionary Theory
- ) Because there are fossil remains of ancient life, we should be able for find some evidence for evolutionary change
- ) We should be able to find some cases of speciation in the fossil record with one line of descent diving in to two or more.
- ) We should be able to find examples of species that link together major groups suspected to have common ancestry.
- ) We should expect that species show genetic variation for many traits.
- ) We should find imperfect adaptations
- ) We should see natural selection occur in nature
Glossopetrae
“Tongue Stones” ; Steno dissected a shark and found that these stones were actually shark teeth (proving that fossils were once living and therefore organic in origin)
Principle of Original Horizontality
strata originally deposited horizontally or nearly so; departures indicate that strata have moved after their formation
Faunal Succession
based on the observation that sedimentary rock strata contains fossilized flora/fauna
- these fossils succeed each other vertically in a specific, reliable order that can be identified over wide horizontal distances
Leonardo da Vinci (objections to Diluvialism)
- ) some shells were too fragile to have traveled great distances
- ) some fossils in strata appeared to be in living positions and resembled living communities
- ) multiple layers of fossil-rich strata separated by unfossiliferous strata (multiple depositional events)
William “Strata” Smith
- coined the term ‘faunal succession’
- made the first geological map of England when he was commissioned to build the canals
Biostratigraphy
the use of fossils and how fossils resemble change between sedimentary layers to date rocks
Robert Hooke
- argued for the organic origin of fossils
- suggested that fossils were the remain of extinct organisms and that species have a ‘limited lifespan’
- said that fossils could be used to correlate strata (biostratigraphy!)
Principle of Original Lateral Continuity
strata originally deposited continuously; if interrupted by gaps in the same strata it indicates rocks have been removed after they’ve formed
3 Properties of an “Index Fossil”
- ) easily identifiable
- ) Geographically and Environmentally widespread
- ) Short stratigraphic range (only exist for a brief amount of time)
3 Types of Unconformities
- ) Angular
- ) Disconformity
- ) Nonconformity
Alcide d’Orbigny
- believed that new species were being created in the wake of each catastrophe (each extinction event)
Georges Cuvier’s Significance of Unconformities
catastrophes are what explains unconformities and extinctions
- life moves toward its perfect state with each catastrophe
Modern Doctrine of Actualism
modern geology is a combination of gradualism and catastrophism
- only assumption that is made today is that the principles of nature have been uniform through time
Charles Lyell
- wrote “Principles of Modern Geology”
- believed that the present is the key to the past and that there is unconformity in nature
- advocated for GRADUALISM not CATASTROPHISM
Disconformity
flatline sediments resting on other flatline rocks and visible erosion
Cross-Cutting Relations
- molten rock can intrude into older, pre-existing rocks
- molten rocks can enclose older pre-existing rock
- relative timing (age) can be determined by this relation
Uniformitarianism
using present processes to understand the past in recorded rocks
Unconformities
a surface erosion and/or non-deposition separating two rock bodies
- represents missing time
Rock Cycle
Earth’s change is a cyclical cycle
- the formation of new rocks balanced by the destruction of old