Explore key concepts and research through these links to additional web resources.

16.1 Species Concepts

• What is a Species and What is Not?
  In this paper from the journal The Philosophy of Science, Mayr explains the biological species concept in the context of the larger question of whether or not species exist in nature. He also offers his critique of alternative species concepts, including the typological (morphological), evolutionary, and phylogenetic species concepts.
  Keywords: speciation, evolution, phylogenetic
• Species Concepts and Crossbills
  At this site, Jeff Groth of the Department of Ornithology at the American Museum of Natural History discusses species concepts in the context of a specific research question about the specific status of crossbills.
  Keywords: species, crossbills, research
• Biological Species Concept (BSC)- A critique
  From the Talk.Origins archive, this paper discusses different species concepts and processes of speciation, and provides an overview (with references) of instances in which speciation has been observed, either in the field or in laboratory populations.
  Keywords: BSC, speciation, research

16.2 Mechanisms of Genetic Isolation

• Ngorongorro crater Lions: the hazards of genetic isolation
  What are the hazards of genetic isolation for a given species? This article used the fate of lions of the Ngorongorro crater as an example.
  Keywords: genetic isolation, speciation, Ngorongorro
• Speciation Events
  From the Talk.Origins archive presents common questions and answers about mechanisms of speciation.
  Keywords: speciation, research, reference

16.3 Mechanisms of Divergence

• Volcanic Winter and Genetic Divergence
  From the Science Daily archive, this paper discusses a new hypothesis about recent human evolution following a volcanic winter. This bottleneck in population size is thought to have brought about genetic divergence.
  Keywords: volcanic winter, genetic divergence, hypothesis

16.4 Secondary Contact

• Hybridization
  This article from Science Daily discusses a 'fast changing gene' in the fruit fly that stops different species from mating.
  Keywords: fruit fly, research, hybridization

16.5 The Genetics of Speciation

• Species Conservation
  This is an organization of scientists engaged in a variety of political issues with a strong basis in science. One issue of major concern is the potential consequences of new uses of biotechnology, including the use of genetically engineered crop plants.
  Keywords: conservation, speciation, politics