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INDISTINCT BACTERIAL STRAINS. "In many laboratory notebooks, there are results of tests of a few strains of different species that gave promise of great usefulness in characterizing species, but, after application of these tests to more strains of each species, the great promise dwindled to nothing because we are dealing with spectra of strains or sections of a spectrum, not with compact packages of strains." https://lnkd.in/exx_wqw View in LinkedIn

SPECTRAL SPECIES. "The different kinds of bacteria are not separated by sharp divisions but by slight and subtle differences in characters so that they seem to blend into each other and resemble a spectrum.” https://lnkd.in/exx_wqw View in LinkedIn

SMALL PRINT PROBLEMS. "A species is often defined as a group of individuals that actually or potentially interbreed in nature. In this sense, a species is the biggest gene pool possible under natural conditions. The definition of a species as a group of interbreeding individuals cannot be easily applied to organisms that reproduce only or mainly asexually. Also, many plants, and some animals, form hybrids in nature. Should they be considered the same species or separate species?" https://lnkd.in/e3Bgi6R View in LinkedIn

SPECIATION MYSTERY. "Called the "mystery of mysteries" of Darwin, speciation is still a little understood area of evolution. One of the greatest problems of biology is how a continuous process of evolution can produce the morphologically discontinuous groups known as species...how many genes must change to make a new species?" https://lnkd.in/e5DqiMq View in LinkedIn

THE GNARLY CRUX. "Charles Darwin himself declined to define the concept in his landmark book “On the Origin of Species.” “Darwin, when he proved that species evolved, also proved there was no such thing as species,” said James Mallet, an evolutionary biologist at Harvard University. If organisms are constantly evolving, then drawing a precise dividing line between two different species will necessarily be difficult." https://lnkd.in/eKBjZs5 View in LinkedIn

SPECIES AS FUNDAMENTAL UNITS. "Readers of Systematic Biology hardly need to be reminded of the importance of species in biology. According to various authors, species are one of the fundamental units of biology, making them comparable in importance to genes, cells, and organisms, some of the fundamental units at lower levels of biological organization." https://lnkd.in/edvh3zR View in LinkedIn

"SPECIATION is how a new kind of plant or animal species is created. Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics. The demands of a different environment or the characteristics of the members of the new group will differentiate the new species from their ancestors." https://lnkd.in/eDjpa_F View in LinkedIn

"A BIOLOGICAL SPECIES is a group of interbreeding or potentially interbreeding organisms that can produce viable offspring." (Ernst Meyer, 1942). View in LinkedIn

TAXONOMY. "Cowan defined taxonomy as composed of three ingredients: (i) classification, (ii) nomenclature, and (iii) identification of the unknown. At present, in taxonomy, the tail certainly wags the dog! Nomenclature, the least important ingredient and the least time-consuming, has its Code and Rules; classification, the most important ingredient of taxonomy, has nothing." https://lnkd.in/exx_wqw View in LinkedIn

GENE AMPLIFICATION. "A surprising result of phylogenetic analyses is the relatively small proportion (10–20%) of the mitochondrial proteome displaying a clear α-proteobacterial ancestry. A large fraction of mitochondrial proteins typically has detectable homologs only in other eukaryotes and is presumed to represent proteins that emerged specifically within eukaryotes." https://lnkd.in/e8CjRNK View in LinkedIn