AY Honors/Fossils/Answer Key

2. Have a brief definition of each of the following in your notebook:

a. Geology

Geology is the science and study of the solid matter that constitutes the Earth.

b. Fossils

Fossils are the mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, and other organisms.

c. Catastrophism

Catastrophism is the idea that Earth has been affected by sudden, short-lived, violent events that were sometimes worldwide in scope.

d. Paleontology

Paleontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils.

e. Graptolite

A Graptolite is a fossil colonial animal known chiefly from the Upper Cambrian through the Lower Carboniferous (Mississippian) periods.

f. Trilobite

Trilobites are extinct arthropods that form the class Trilobita. They appeared in the 2nd Epoch (Series 2) of the Cambrian period and flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Late Devonian extinction, all trilobite orders, with the sole exception of Proetida, died out.

g. Dinosaur

A dinosaur is any of various extinct reptiles.

h. Mammoth

A mammoth is any species of an extinct genus of proboscidean (elephants and their extinct relatives), often with long curved tusks and, in northern species, a covering of long hair.

i. Mastodon

Mastodons are members of the extinct genus Mammut of the order Proboscidea and form the family Mammutidae; they resembled, but were distinct from, the woolly mammoth which belongs to the family Elephantidae. Mastodons were browsers and mammoths were grazers.

j. Crinoid

Crinoids, also known as "sea lilies" or "feather-stars", are marine animals that make up the class Crinoidea of the echinoderms (phylum Echinodermata). There are only a few hundred known modern forms, but crinoids were much more numerous both in species and numbers in the past. Some thick limestone beds dating to the mid- to late-Paleozoic are entirely made up of disarticulated crinoid fragments.

k. Lingula

Lingula is a genus of brachiopods.

l. Calamite

A fossil made when sediment filled the hollow stem of a plant.

m. Foraminifera

The Foraminifera are a large group of unicellular organisms with reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net. They typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in structure. About 275,000 species are recognized, both living and fossil.

n. Radiolaria

Radiolaria are amoeboid protozoa that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm. They are found as zooplankton throughout the ocean, and because of their rapid turn-over of species, their tests are important diagnostic fossils found from the Cambrian onwards.

o. Paleozoic

The Paleozoic Era is the earliest of three geologic eras of the Phanerozoic eon. The Paleozoic era is defined by geologists as spanning from roughly 542 million years ago to roughly 251 million years ago.

Phanerozoic eon
Paleozoic era	Mesozoic era	Cenozoic era

p. Mesozoic

Lying between the Paleozoic and the Cenozoic, Mesozoic means 'middle animals'. It is often called the 'Age of the Dinosaurs',

q. Cenozoic

The Cenozoic Era is the latest of three geologic eras of the Phanerozoic eon. Geologists define this era as having started about 65 million years ago, when the age of the dinosaurs ended.

r. Pleistocene

The Pleistocene epoch on the geologic timescale is the period from 1,808,000 to 11,550 years before present. The Pleistocene epoch had been intended to cover the world's recent period of repeated glaciations, or the Ice Age.

s. Paleobotany

Paleobotany is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments. Paleobotany includes the study of terrestrial plant fossils, as well as the study of prehistoric marine photoautotrophs, such as photosynthetic algae, seaweeds or kelp.

t. Pelecypod

Pelecypod are molluscs belonging to the class Bivalvia. They typically have two-part shells, with both valves being symmetrical along the hinge line. The class has 30,000 species, including scallops, clams, oysters and mussels.

u. Brachiopod

Brachiopods are two-shelled marine animals with an external morphology superficially resembling pelecypods (for instance, clams) of phylum Mollusca to which they are not closely related. It is estimated by paleobiologists that 99 percent of all documented lamp-shell species are both fossils and extinct.