Test or Shell
Simple tests (or shells) are be made by either secretion (autogenous tests) or by the agglutination of foreign material (xenogenous tests), or sometimes a combination of both. Past environmental changes can be determined by analysing the composition of fossil tests, including the reconstruction of past climate change.
Read more about this topic: Arcellinida
Famous quotes containing the words test and/or shell:
“The test of an adventure is that when you’re in the middle of it, you say to yourself, “Oh, now I’ve got myself into an awful mess; I wish I were sitting quietly at home.” And the sign that something’s wrong with you is when you sit quietly at home wishing you were out having lots of adventure.”
—Thornton Wilder (1897–1975)
“I was even more surprised at the power of the waves, exhibited on this shattered fragment, than I had been at the sight of the smaller fragments before. The largest timbers and iron braces were broken superfluously, and I saw that no material could withstand the power of the waves; that iron must go to pieces in such a case, and an iron vessel would be cracked up like an egg- shell on the rocks.”
—Henry David Thoreau (1817–1862)