GEO 103 - Lesson 4

Modifications for living in a certain way and performing particular functions

Adaptations

Another division of the marine ecosystem (aside from pelagic), the "bottom"

Benthic realm

When burrowers churn and mix sediment, resulting in destruction of original grain orientations in clastic sediments

Bioturbation

A body of rock that is identified strictly on the basis of its contained fossils

Biozone

Occurs when soft tissues are preserved as thin films of carbon

Carbonization

In drilling for oil, geologists recover Devonian conodonts in a stratum known to be Permian in age. Explain how this may have occured

Conodonts are made of the durable mineral apatite. The conodont in question was eroded from a Devonian layer (along with quartz sand grains), was transported by wind and water, and was then deposited into a layer of sediment during the Permian. This is known as a reworked fossil

Mollusks, crustaceans, and fish are considered...

Consumer organisms (carnivores)

Species not restricted to any single geographic location within a terrestrial environment

Cosmopolitan species

A chronostratigraphic (time-rock) unit contains a different fossil assemblage at one locality than another located 200 km away. Suggest a possible cause for the dissimilarity.

Ecological differences

Species confined to a particular geographic location

Endemic species

Benthic animals that live on top of the sediment that carpets the sea floor

Epifaunal

The remains or traces of ancient life

Fossils

The interval between the first and last appearance of a species

Geological range

The places where an organism lives

Habitat

The study of trace fossils

Ichnology

Fossils that are abundant, widely dispersed, and derived from organisms that lived during a relatively short span of geological time

Index/guide fossils

Benthic animals that burrow in the soft sediment for food and protection

Infaunal

Area between high and low tide, creatures must be able to tolerate wet and dry conditions here

Littoral zone

True swimming animals; in the pelagic realm

Nekton

The particular role played by the animal or plant as it interacts with all the physical, chemical, and biologic elements of its immediate environment

Niche

Using fossils for age correlation is dependent on a priori knowledge of their age ranges. How has this knowledge been obtained?

Observing fossil occurrences in rock layers from the past 200 years

The study of the interaction of ancient organisms with their environments

Paleoecology

Biological components of marine ecosystems are classified according to their so-called trophic, or feeding, level. Which of the following is a producer organism as contrasted with a consumer organism?

green plant

The technical term for the intertidal zone is

littoral

Which of the following is a trace fossil?

mammoth footprint

A marine organism that lives in the water column, between a depth of 0 to 1000 meters, and is an active swimmer is best classified as a(n)

pelagic, nektonic organism

The addition of a chemically precipitated substance into pore spaces

permineralization

Imagine finding a large brachiopod comprised of fool's gold (pyrite). Since brachiopods make their shells out of calcite, it is obvious that this shell has undergone some kind of change during the fossilization process. The specific alteration process displayed by this brachiopod is

replacement

Fossil A occurs in rocks of Cambrian and Ordovician age. Fossil B occurs in rocks that range in age from early Ordovician through Permian. Fossil C is Found in Mississippian through Permian strata. What is the max possible range for a stratum containing both Fossils A and B?

Ordovician

The science that seeks to understand all aspects of the succession of plants and animals over that great expanse of geological time

Paleontology

Small animals and plants that float, drift, or feebly swim in a marine ecosystem

Plankton

Green plants are considered...

Producer organisms (herbivores)

The rock body representing the total geologic life span of a distinct group of organisms

Range zone

A measure of how much biological change has occurred over a given interval of geological time

Rate of evolution

A simultaneous exchange of the original substance of a dead plant or animal with mineral matter of a different composition; dissolved the original material and replaces it with an equal volume of the new substance

Replacement

What factors determine whether or not a particular fossil will be valuable as an indicator of the age and correlation of a stratum?

Short geological range and widespread geological distribution

Fossil A occurs in rocks of Cambrian and Ordovician age. Fossil B occurs in rocks that range in age from early Ordovician through Permian. Fossil C is Found in Mississippian through Permian strata. What is the max possible range for a stratum containing only Fossil B?

Silurian and Devonian

Benthic animals and plants are most abundant here, extends from low tide levels down to the edge of the continental shelf

Sublittoral zone

The zone above high tide, harsh area

Supralittoral zone

A group of organisms that constitute a particular taxonomic category, such as species, genus, and family

Taxon

left-over tracks, trails, burrows, and borings

Trace fossils

Biologic components of the ocean ecosystem

Trophic levels

The study of processes affecting a fossil organism from the time of its death until final burial is called

biostratinomy

On a continuum from minor disruption to severe damage, which of the following biostratinomic processes does the least violence to a potential fossil?

reorientation