Paleontology - midterms (ppt)

• Paleoecology


  the study of the life and times of fossil organisms, the lifestyles of individual animals and plants together with their relationships to each other and their surrounding environment.
• a. Mutualism

  b. Commensalism

  c. Predation

  d. Parasitism

  e. Competition


  Forms of interaction / symbiosis:
• paleoautecology

  paleosynecology


  Subdivisions of paleoecology:
• paleoautecology


  the behavior of individual organisms and their relation to the environment
• paleosynecology


  the ecology of communities of organisms and their relationship to the environment
• Phyletic Gradualism


  Evolution taking place within species lineages
• Punctuated Equilibrium


  Evolution taking place at the time of speciation
• 1. Fidelity

  2. Taphonomy

  3. Time-averaging

  4. Habitat-mixing


  Complicating Factors
• Fidelity


  similarity of a death assemblage to its living counterpart
• Taphonomy


  The suite of processes that affect organismal remains can be compared between organisms of different species or between individuals of the same species
• preservation bias


  What is considered in taphonomy? Process that affect organismal remains.
• Time-averaging


  individuals in an assemblage did not live together at the same time. Instead, years, decades, centuries, or even longer periods of time may have passed between the times when the individuals were alive
• Habitat mixing


  the extent to which individuals from different habitats have been mixed together in a fossil assemblage
• uniformitarianism

  paleocommunity


  two common assumptions -- assumptions made in any given study are often specific to that study and the data that are available
• Uniformitarianism


  a commonly used assumption in the geological sciences based on the premise that processes and organisms in the past functioned similarly to processes and organisms we observe today
• Paleocommunity


  Another common assumption in paleoecology is that the organisms found in a fossil assemblage can be considered as a community.

  
  

  can be considered a recurring collection of associated species or a recurrent group of organisms related to some specific set of environmental conditions or limiting factors.
• Paleoenvironmental Reconstruction


  Attempts to describe past environments
• temperature,

  water depth,

  precipitation,

  water salinity


  abiotic factors of paleoenvironmental reconstruction
• proportions of herbivores and predators

  number of species in a fossil assemblage.


  biotic factors of paleoenvironmental reconstruction
• 1. Types of sediments and features preserved in them

  2. Taphonomic factors

  3. Degree to which fossils are disarticulated

  4. Climate data from tree rings, ice core and other sources

  5. Organisms in the assemblage


  Information needed to reconstruct a paleoenvironment
• Proxy


  gives information about a factor, even if it does not directly measure something about that factor
• dendrochronology


  Most studies of tree rings
• Ice cores


  Another way of providing a high-resolution record of the past climate but have a somewhat limited duration of applicability
• Sediments


  physical matter found in the natural world and subject to processes like weathering and erosion
• Disarticulation


  describes the extent to which the skeletal components of an organism have remained intact as a fossil relative to how the components were oriented in the living organism
• Marine: Wave action

  Land: Scavengers

  Both: Erosion


  Processes that could lead to disarticulation
• trade-off


  When an organism is well suited for a particular condition (like mounded corals being able to cope with wave impacts), it usually comes at the cost of something else
• Chemical composition


  The high-resolution record in coral skeletons also makes them ideal candidates for biogeochemical analysis.
• Biogeochemistry


  the study of the integrated biological, geological, and chemical processes and reactions that dictate the dynamics of natural environments
• Isotopes


  Atoms containing a greater or lesser number of neutrons than typically found in an atom of the element
• 18O

  16O


  Oxygen isotopes
• 18O


  An oxygen isotope that has greater mass, when incorporated into a water molecule, it is less likely to evaporate (if all else is equal)
• 16O


  An oxygen isotope that is more likely to evaporate and return to Earth as freshwater precipitation. Thus, ocean water can be said to be "heavy" compared to freshwater
• Paleoclimates


  can be described on the basis of climatically-sensitive biotas and sediments together with stable isotopes
• Charles Darwin


  The scientist who gave us phylogenic trees and biodiversity
• sexual selection


  A male organism finding a willing female; mating
• natural selection


  An organism trying to avoid a predator
• adaptation


  an aspect of form that performs a physical or behavioral function
• 1. Form is the only evidence we have in fossils for identifying species and wider relationships to reconstruct the tree of life

  2. Form can tell us about behavior and ecology

  3. Variations in form are common place within a species, and the study of changes in form through time informs us about evolution


  Importance of form fossils
• biological species concept


  What concept should be applied for modern plants and animal?