Transcript Biodiversity and Paleontology One: PowerPoint Presentation

Who studies paleontology?
•morphologists: interested in structures and function
•evolutionary biologists: support for evolutionary theory
•systematists: interested in phylogenetic relationships of
extant and extinct animals
•paleontologists: interested in structures for identification of
extinct animals
HOMOLOGY vs. ANALOGY
Homology: share a recent common ancestor
Homologies are established by:
•fossil record, historical biogeography
•embryology, comparative anatomy (e.g., topographic location)
•genetics (DNA, molecular sequence data)
Homologous structures do not have to look alike (e.g., bird beaks,
feet, or feathers) but they do share a recent common ancestor.
Analogy: shared function, but no recent common ancestor
Analogous structures often appear similar (superficially) because of
their function
e.g., penguin wing / dolphin fin
shark fin / ichthyosaur fin
The Rock Cycle
Slide of the rock cycle and importance of
sedimentary rocks to the rock record and
fossilization.
Fossils are found in Sedimentary Rocks. The rocks can be:
•detrital: physical break down of pre-existing rocks
•chemical: produced by chemical precipitating dissolved
minerals out of solution.
The minerals are in solution from chemical weathering of
preexisting rocks.
Transportation and deposition processes: ice (glaciers),
water (rivers, streams, oceans), and air (loess).
Transportation is related to the amount of energy in the
system.
Depositional Environments
•Continental environments: e.g., fluvial, desert, glacial
•Transitional environments: e.g., beach, delta, barrier
islands.
•Marine environments: e.g., continental shelf, carbonate
platform, continental slope and rise, deep-ocean basin,
evaporite environments.
Paleoenvironmental interpretations are based upon the
evidence found in the rocks, e.g., organisms, niche,
habitat, water depth, etc.
Different environmental settings form little or no deposits,
while other deposits become soils.
Lithification is the process of compaction and/or cementation.
Sandstone
Sand is a particle size and sandstone is a composite.
Most sandstone is made up of quartz and a few other
minerals.
For minerals to become sedimentary rock they must be
available, mechanically durable, and chemically stable.
Typical sedimentary rock facies include: sand facies, mud
facies, and carbonate (limestone) facies.
Marine transgressions and regressions are major worldwide
events that are recorded in the rock record. They are used
to hypothesize correlations of eustatic sea levels (rise and
fall).
Examples of sedimentary structures are: strata or
beds, graded beds, paleo-currents, and mud cracks.
Fossils are found in an altered condition, e.g.,
permineralized and an unaltered condition, e.g.,
mummification.
Types of fossils can be body or trace fossils or coprolites.
Fossilization as a process includes: petrified,
permineralization, and carbonized.
Requirements for permineralization include: rapid burial,
mineral rich water percolating through the sediments,
and time.
Erosion exposes fossils to a trained observer.
Geologic Time
Relative versus Absolute time
Fundamental principles of relative time are the principle of
uniformitarianism, superposition, lateral continuity,
cross-cutting relationships, inclusion, and fossil
succession.
Principles of relative dating and the geologic maps explain
ideas like correlation and include key beds and guide
fossils.
Geologic maps also include information, e.g., unconformity
(disconformity, angular unconformity, and nonconformity)
and what is a hiatus (missing data).
Relative versus Absolute Time
Fossil Succession
Lateral Continuity
Singular History of
Life on Earth
Origin of Life
3800 Million Years Before Present
Submarine Hydrothermal Vent
Age of Stromatolites
2500 Million Years Before Present
Prokaryotic and Eukaryotic Cells
Major Episodes in
the History of Life