Exam 12: Paleozoic Life History Invertebrates

All bottom-dwelling marine organisms that live on the seafloor or within seafloor sediment are ____.

Organisms that belong to the benthos are classified primarily by ____.

All of the organisms that live on or in the seafloor are part of the benthos.

The ____________________ are tooth-like calcium phosphatic fossils that are excellent index fossils for the Ordovician.

The most likely way volcanic activity could have directly contributed to the Permian mass extinction is by ____.

The Great Biodiversification Event occurred during the ____.

How can we classify phytoplankton within a food web?

If you were transported back in time to the Cambrian Period, the mobile marine organisms that would be most unique to that period would be ____.

The ammonoids are excellent guide fossils because of distinctive physical features, short species ranges, and a wide geographic distribution.

Organisms that comprised reef complexes remained virtually unchanged during the Paleozoic.

In Charles Darwin's day, the fossil record began abruptly with the appearance of shelled organisms. Today, we consider the same period-the Cambrian-as an "explosion" of life forms. Why has this perspective changed?

The mass extinction in the geologic record, which proved to be the most devastating to life on Earth, occurred at the end of the ____.

The Permian extinction killed approximately ____ of all marine invertebrate species.

Describe and discuss mass extinctions during the Paleozoic and Mesozoic. How do these mass extinctions differ?

Ammonoids, graptolites, and conodonts are excellent guide fossils because of their short stratigraphic ranges and wide geographic ranges.

Bacteria break down dead organisms into organic compounds. Therefore, they function as ____________________ in the food web.

Benthic organisms that move through or live in the sediment are called ____________________.

The extinction event at the end of the Permian affected only land-dwelling organisms.

Plankton and nekton are different because ____.

There is no evidence in the geologic record that multicellular organisms of any kind existed prior to the Cambrian.