what other works has he done?
He published "Systematics and the Origin of Species"
Ernst Mayr
 In his book "Systematics and the Origin of Species" (1942) 
define species as a group of organisms that can reproduce to produce fertile offspring UNANSWERABLE what species means? A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring,  In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. is there any famous concept followed regarding this? Yes, Most modern textbooks make use of Ernst Mayr's 1942 definition, known as the Biological Species Concept as a basis for further discussion on the definition of species. It is also called a reproductive or isolation concept. who was he? He was a renowned taxonomist, tropical explorer, ornithologist, philosopher of biology, and historian of science. when was he born? 5 July 1904
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Ernst Mayr [SEP] Introduction
Mayr is sometimes credited with inventing modern philosophy of biology, particularly the part related to evolutionary biology, which he distinguished from physics due to its introduction of (natural) history into science.