Editing Zoology (section)

==Scope==
Zoology is the branch of science dealing with [[animal]]s. A [[species]] can be defined as the largest group of organisms in which any two individuals of the appropriate sex can produce fertile offspring; about 1.5 million species of animal have been described and it has been estimated that as many as 8 million animal species may exist.<ref>{{Cite journal |last1=Mora |first1=Camilo |last2=Tittensor |first2=Derek P. |last3=Adl |first3=Sina |last4=Simpson |first4=Alastair G. B. |last5=Worm |first5=Boris |date=2011-08-23 |title=How Many Species Are There on Earth and in the Ocean? |journal=PLOS Biology |volume=9 |issue=8 |pages=e1001127 |doi=10.1371/journal.pbio.1001127 |issn=1545-7885 |pmc=3160336 |pmid=21886479 |doi-access=free }}</ref>
An early necessity was to identify the organisms and group them according to their characteristics, differences and relationships, and this is the field of the [[taxonomy|taxonomist]]. Originally it was thought that species were immutable, but with the arrival of Darwin's theory of evolution, the field of [[cladistics]] came into being, studying the relationships between the different groups or [[clade]]s. [[Systematics]] is the study of the diversification of living forms, the evolutionary history of a group is known as its [[Phylogenetic tree|phylogeny]], and the relationship between the clades can be shown diagrammatically in a [[cladogram]].<ref name="Ruppert">{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |page=2 }}</ref>

Although someone who made a scientific study of animals would historically have described themselves as a zoologist, the term has come to refer to those who deal with individual animals, with others describing themselves more specifically as physiologists, ethologists, evolutionary biologists, ecologists, pharmacologists, endocrinologists or parasitologists.<ref name=Campbell>{{cite book |author=Campbell, P.N. |title=Biology in Profile: A Guide to the Many Branches of Biology |url=https://books.google.com/books?id=tQTLBAAAQBAJ |year=2013 |publisher=Elsevier |isbn=978-1-4831-3797-1 |pages=3–5 |access-date=2021-06-18  |archive-date=2024-06-12  |archive-url=https://web.archive.org/web/20240612073719/https://books.google.com/books?id=tQTLBAAAQBAJ |url-status=live }}</ref>