Is there a single species definition that can define all species?
No but its a real thing, difficult to define because speciation is a process not an event
If not, does this mean that the concept of a species is a human idea and not a biological reality?
complex process rather than a single event
How can we reconcile this discrepancy
recognizing its a process
evolutionary species concept
lineage of populations which maintains identity from other such lineages and which has its own evolutionary tendencies and historical fate.
3 ways to define species
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Morphological species concept
organisms look different from other species. dichotomous key
strengths: time efficient and no equipment needed
weakness: education on terms (technical expertise), not enough morphological diversity to -
Biological species concept
used by defining rates of gene flow. can they exchange genetic material and at what level? only related to sexually reproducing species. groups of potentially interbreeding populations which are reproductively isolated from other such groups.
strengths: more scientific and objective method
weaknesses what point do we draw the line? Takes time and effort, asexually reproducing species
Phylogenetic species concept
smallest clade in a monophyletic group and call it a species. objective methodology. smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestry and descent.
strenghts
weaknesses: difficulties in asexual species, takes time and effort
Others
Ecological species concept - based on the way a species makes a living, what is their niche?
Review Wheeler paper and his arguments for the Phylogenetic Species concept PSC being the single, unifying species concepts
There really is no single one.
What biological process does the PSC have a particular problem with?
HGT. creates networks and there's no clear way to define connections. asexual reproducers.
Geographic separation
force that causes speciation (allopatric speciation)
competition for resources is driving source
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