Editing Fossil (section)

=== Limitations <span class="anchor" id="Fossil record limitations"></span>===
<!-- use anchor because other articles link to this section, and a change to its name recently broke such a link -->
{{Further|Ghost lineage|Signor–Lipps effect|Biostratigraphy}}

Organisms are only rarely preserved as fossils in the best of circumstances, and only a fraction of such fossils have been discovered. This is illustrated by the fact that the number of species known through the fossil record is less than 5% of the number of known living species, suggesting that the number of species known through fossils must be far less than 1% of all the species that have ever lived.<ref name=Prothero2007pp5053>{{cite book |author-link=Donald Prothero |last=Prothero |first=Donald R. |date=2007 |title=Evolution: What the Fossils Say and Why It Matters |url=https://archive.org/details/evolutionwhatfos00prot_0/page/50 |url-access=registration |pages=[https://archive.org/details/evolutionwhatfos00prot_0/page/50 50–53] |publisher=[[Columbia University Press]] |isbn=978-0-231-51142-1 }}</ref> Because of the specialized and rare circumstances required for a biological structure to fossilize, only a small percentage of life-forms can be expected to be represented in discoveries, and each discovery represents only a snapshot of the process of evolution. The transition itself can only be illustrated and corroborated by transitional fossils, which are never guaranteed to demonstrate a convenient half-way point.<ref name="CC200">{{cite web|url = http://www.talkorigins.org/indexcc/CC/CC200.html|title = Claim CC200: There are no transitional fossils.|access-date = 30 April 2009|date = 5 November 2006|publisher = [[TalkOrigins Archive]]|last = Isaak|first = M|archive-url = https://web.archive.org/web/20090227065512/http://www.talkorigins.org/indexcc/CC/CC200.html|archive-date = 27 February 2009|url-status = live}}</ref>

The fossil record is strongly biased toward organisms with hard parts, leaving most groups of [[soft-bodied organism]]s with little to no presence.<ref name=Prothero2007pp5053 /> It is replete with [[Mollusca|mollusks]], [[vertebrate]]s, [[echinoderm]]s, [[brachiopod]]s, and some groups of [[arthropod]]s.<ref>{{cite book|editor=Donovan, S. K.|editor2=Paul, C. R. C. |date= 1998 |title= The Adequacy of the Fossil Record |publisher=Wiley |location= New York |page= 312 |isbn=978-0-471-96988-4}}{{page needed|date=August 2014}}</ref>