species concepts Flashcards
how can sex be diffucult for defining species
organisms of the same species may differ in how they appear but are the same organisms
hard to classify
whats the issue with develolment in terms of species definitions
some organisms have morphs and casts
they vary but are the same species despite genetic variation
how can oncology/development affect species definitions
different life stages can be misstaken for different species
happens in fossil records commonly
issues arising when defining species
sexes casts/morphs intraspecicif variation convergent evolution developmental stages
what is horizontal species concepts
how species differ in their current phenotpic ecological or biological characteristics
what is vertical species cnceptrs
how the DNA code has been moduclated by evolutionary processes over time
describe the phenetic species concepts
character based
descriptive
statistical
extension of taxonomic characteristics for definition
key limitations of the phenetic species concept
intraspecific variation
convergent evolution
only looks so easy to classify wrong
what is the ecological species concept
shared ecological niches
phentic clusters formed we recognise these as species becase the ecological and evloutionary processes control how resources are divided up tend t make these clusters
limitations of the ecological species concept
discrete envrionments
ontongeny
hard to define a niche
what is the biological species concept
species are a group of interbreeding, natural populations that are reproductively isolated form other such groups
cant reporoduce with others not in their species, made infertile offspring
issues with the biological species concept
cant test always
application to microbes, fungi, plants?
asexual reproduction
what are prozygotic barriers?
bechanioural and morhological barriers to prevent breeding
what are postzygotic barriers
hybrid inviability, sterility, breakdown of the zygotie
when sperm meets egg it breaksdown
what is the phylogentic species concept
increasing use of DNA sequence data to make phylogenies
members of one spcies should mkae distinct clusters or monophyletic clades
what is the cryptic species complex
DNA barcoding used to reveal genetic species
what is a crypic species
one morpho spcies proves to ave distict genetic units
how are ecological clines related to species
often respresent adaptations to locan conditions such as: abiotic climate biotic species interactions
how can genetic clines be made?
through a lack of gene flow
how can distinct polulations have the same gene frequences despite little or no gene flow
populations have no diverged significantly at severl loci
selection actively maintinas genetic diversity
what is a ring species
no common
but an example of speciation on a continuum
subspecies blend into each other and can intebreed but progressively divide from each other
only adjacent species can breed
why are microbes hard to classify into species
HGT
asexual
