Historical Geology - Evolution Flashcards
What is evolution?
differential reproductive success of genes within a population.
- change through time
What was Jean Baptiste Lamarck basic theory?
Species adapted to their environment
What was Darwin’s basic theory?
natural selection
Who came up with the idea of natural selection?
Alfred Russell Wallace
What is natural selection?
- fitness = probability of successful reproduction
- inheritable traits that increase fitness are more likely to be passed on to subsequent generations
What are genetics?
offspring inherit genetic material from their parents
What was Jean Baptiste Lamarck basic theory? What was his mistake?
Species adapted to their environment. the Mistake he made is that organisms do not pass down acquired traits.
What is mutation?
permanent changes in the DNA sequence
Kinds of mutations?
Deletions - DNA base pair is removed from strand
Inversions - DNA bases are reversed in order
Duplications - DNA sequence is erroneously repeated
Do mutations drive evolution?
No
What do mutations do?
Help provide genetic variation within a population which can be acted upon by natural selection to cause evolution.
Why is population size important in evolution?
- Larger populations have more genetic inertia (material) and more variability so they evolve more slowly and selectively
- smaller populations evolve rapidly and have less variability making them more vulnerable to extinction
What is speciation?
The process through which a new species is formed.
Kinds of mutations? Explain each.
Deletions - DNA base pair is removed from strand
Inversions - DNA bases are reversed in order
Duplications - DNA sequence is erroneously repeated
What are the modes of speciation? explain each.
Phyletic grandualism - evolution occurs at a constant rate, speciation gradual process
Punctuated equilibrium - taxa exist for long periods of time with little net genetic and/or morphological change with speciation taking place rapidly.
Does evolution ever stop? Explain.
No. The environment applies constant selective pressure to populations. Even when no morphological changes happen genetics are still changes via genetic recombination (sexual reproduction, mutation, natural selection)
What is convergent evolution?
Taxa from separate evolutionary lineages converge upon similar body plans or adaptations. fish - reptile - mammal
What is Dollo”s Law?
In general, evolution is not a reversible process.
How do we track biodiversity in the fossil record?
Rates of origination and extinction.
Explain Origination Rate.
rate at which new taxa evolve/are found in the fossil record.
What is extinction?
The end of a genetic lineage.
What is background extinction rate?
The rate at which taxa go extinct through geologic time.
When does mass extinction occur?
When the extinction rate increases and overwhelms the origination rate.
Name the 5 mass extinctions in the history of the planet.
- End Ordovician
- End Devonian
- Permo-Triassic
- End Triassic
- End Cretaceous
what is the 6th mass extinction likely to be caused by?
Humans
What is the Biological Species concept?
Members of a population that can breed and produce viable offspring.
What is the Morphological Species concept?
Species differentiated on the basis of morphological (physical) differences.
What is a fossil?
Remains or traces of past life preserved in the rock record.
What is Taphonomy?
The science that
- seeks to understand natural processes so that data from fossil record can be evaluated correctly
- seeks to understand the processes involved in creation preservation
- seeks to understand the physical, biological, chemical, geological, and anthropological processes involved in the creation, preservation, and collection of fossils
What are the Preservational Controls?
- Rate, quantity, and composition of remains
- Environmental conditions (pre-burial)
- Time to burial
- Post-depositional sedimentary conditions
- Fate of sediments once lithified
What are the Taphonomic processes/biases?
- Biochemical fidelity
- Anatomical fidelity
- Spatial fidelity
- Temporal fidelity
- Compositional fidelity
What is Biochemical fidelity?
Alteration of chemical composition.
• Permineralization
• Replacement
• Original material
What is Anatomical fidelity?
modification of physical structure.
• Disarticulation / Dismemberment
• Decomposition
What is Spacial fidelity?
How far it has been transported since death. How many transport events have to be taken into account.
What is Temporal fidelity?
Time-averaging within units and assemblages.
What is Compositional fidelity?
Fossil assemblage accurate representation of source ecosystem.
How do we control for taphonomic
biases?
Recognition of possible biases
Name the 6 ways fossils are formed and describe each.
- Original remains - little to no alteration of remains
- Permineralization - Spaces in microstructure are filled with minerals (forming internal casts)
- Replacement - growth of a secondary material at the expense of the original material
- Recrystallization - change in mineral structure from aragonite to more stable calcite. Results in loss of anatomical detail.
- Dissolution - original material completely removed while not being replaced.
- Trace - Non-body fossils caused by organisms
• Feeding traces
• Footprints
• Root casts
• Burrows
• Coprolites
