3.3 Species
a group of living organisms of similar individuals capable of reproducing viable offspring, that are reproductively isolated.
"On the Origin of Species" 1859
introduced natural selection as a gradual and continuous mechanism of change
"organisms in one or more populations that together form a cohesive, reproductive unit—a separate lineage on its own evolutionary trajectory"
Population Genetics aka The Modern Synthesis
Mathematical pop gen models identified the genetic mechanisms of evolutionary change
1930s - Fisher, Haldane, Wright, Dobzhansky & more
Biological species concept
Mayr 1942
New species formation involves reproductive barriers (pre or post zygotic)
speciation occurs when mating is no longer viable
almost entirely required geographic isolation
1990s Reclassification
Reclassification of modes of speciation to focus on the processes driving genetic divergence over geographical divergence
Genetics/genomics
studies of a whole genome
genomic islands of divergence where a region of genes (single nucleotide to whole chromosome) that exhibits more genetic differentiation than observed randomly
What is a species?
a group of living organisms of similar individuals capable of reproducing viable offspring
Darwin
"On the Origin of Species" 1859
introduced natural selection as a gradual and continuous mechanism of change
"organisms in one or more populations that together form a cohesive, reproductive unit—a separate lineage on its own evolutionary trajectory"
Population Genetics aka The Modern Synthesis
Mathematical pop gen models identified the genetic mechanisms of evolutionary change
1930s - Fisher, Haldane, Wright, Dobzhansky & more
Biological species concept
Mayr 1942
New species formation involves reproductive barriers (pre or post zygotic)
speciation occurs when mating is no longer viable
almost entirely required geographic isolation
1990s Reclassification
Reclassification of modes of speciation to focus on the processes driving genetic divergence over geographical divergence
Genetics/genomics
studies of a whole genome
genomic islands of divergence where a region of genes (single nucleotide to whole chromosome) that exhibits more genetic differentiation than observed randomly
Species ID
in practical modern situations, we rely almost entirely on morphology, geography, and behavior to identify species.
behavior - birds
Nature article on history of evolution & species
The scientific practice of identifying and naming species
Species ID
in practical modern situations, we rely almost entirely on morphology, geography, and behavior to identify species.
behavior - birds
Nature article on history of evolution & species
The scientific practice of identifying and naming species
How would you determine the total number of species on earth?
estimates = 8.7 billion Paper 1
often overlook microbes, bacteria, etc
Estimate with microbes = 1 trillion Paper 2
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