1	SPECIES Many types of information are used to describe, delimit and separate species
2	What is a species? Species, taxa, kinds and types all have similar meanings. Biological individuals can be grouped into clusters of “kinds” that can be named. Individual cats are fairly similar, so we label the kind “cat”. Individual dogs are less similar, but even types that look very different can breed and produce offspring.
3	Species have limited geographic ranges
4	Okanagana balli is the scientific name of the prairie cicada
5	Species are typically composed of geographically distinct populations The ‘colored’ range of a species rarely is occupied everywhere that is colored. Populations of a species are often separate for long times. Considered aquatic organisms- lakes and ponds are typically isolated. Isolation leads to distinctness.
6	Subspecies and varieties Subspecies and varieties are finer levels of distinction than species. Subspecies is typically used for geographically structured morphological distinctions. Individuals in the same species can mate and produce offspring even when in different subspecies.
7	Continuity of Populations It makes sense to include individuals in all populations which share an evolutionary future as well as a past into a single species. The past can be studied, but the future is harder to predict. Human movements of species to new places disrupts natural patterns.
8	Limits of continuity in time Two genes traced backward thru time coalesce (=fuse) into a single line. It is not possible to distinguish at what point in time ancestors should be considered different species (anagenesis) if one uses mating criteria to distinguish species.
9	Biological Species Concept Individuals are members of a single biological species if they share a relatively recent evolutionary past and potentially share an evolutionary future. Individuals that mate and produce offspring should be in the same species even they don’t look alike. The future can be impacted by unexpected extreme events.
10	Biological Species concept Important assumptions Reproductive isolation is a possible relationship of populations. Gene flow between populations reduces their genetic differentiation. Lack of gene flow will eventually result in reproductive isolation.
11	Biological species: Operational evaluation Do matings between individuals produce fertile offspring? Among the difficulties is the fact that negative results are possible between individuals of same population. The biological species criteria applied to individuals with apomictic reproduction or obligate selfers creates too many ‘species’.
12	The Morphospecies Concept Morphological features can be seen and preserved in dead individuals. Preserved individuals in museums provide a reference collection to which future individuals can be compared. Humans are a visual species and applying visual criteria is a ‘natural’ way to distinguish types.
13	Morphospecies usefulness Using morphology to define species enables one to name species that are extinct. Morphology can be applied to individuals that do not have biparental reproduction. Morphological definitions have lumped together biological species that are physiologically distinct, as well as separated things that belong together.
14	Rosa carolina is the scientific name of the Pasture rose
15	Phylogenetic Species DNA sequence information is becoming available for an increasing number of individuals. Measuring similarity of sequences is fairly straightforward. Rules for generating a phylogeny from sequences are available. Polymorphisms within species are not always recent, so large differences can persist in individuals that can mate.
16	Phylogenetic Information trumps Morphological Information Dusky Seaside sparrow A SUBSPECIES not a species. Remaining birds were breed with Gulf coast birds, closest by looks, rather than Atlantic coast birds which were closest by DNA sequence. Biological species concept more in tune with phylogeny than morphology.
17	Spatial Relations of Populations Allopatric Populations living in different places. If there is no contact, they are obviously going their separate ways. Eventually, the separateness will lead to genetic distinctness. Sympatric Populations that live in the ‘same place’ at the ‘same time’. Sympatric Speciation Environmental change that selects for two different types. Mutation which generates instant isolation.
18	Histories of Populations -splitting Both Merging and Splitting occur. A population can be split into two (or more) populations by geological events. The splitting of a population is described as vicariance.
19	Histories of Populations -merging Populations that were spatially separated can become overlapping, when one or more of the populations expands. This is called secondary contact. Sometimes the populations unite into a single species. Sometimes the hybrids are less viable than either populations.
20	Ways Mating Between incipient Species is Reduced Differences in the time of mating. Differences in the place of mating. Behavioral differences in courtship. Mating is attempted, but not completed, because of incompatible genitalia.
21	Nature is Dynamic Populations expand and populations go extinct. There are appreciable rates of colonization and extinction. Recently all arable land has been put to agricultural use. The human spread of species around the globe has greatly changed the biological landscape in the last 150 years.
22	Species Biological populations are differentiated at all possible levels. This means that there is no single definition of “species” that will work in all circumstances. “Species” are partly real distinct swarms of individuals, but our recognition of species (taxa) also reflects the distinctions people feel are valuable.
23	Speciation The emphasis in your book is how to tell if populations existing at the same time are separate species. Our ideas of the continuity of life make it especially difficult, conceptually and practically, to generate rules to define species along a line of descent. We will be satisfied to note the difficulty.
24	Vocabulary Taxa, taxon Subspecies Biological species concept Morphospecies concept Reproductive isolation Phylogenetic species Allopatric Sympatric Vicariance Extinction