more stuffs for final midterm Flashcards
what is speciation
process by which lineages split into independent evolutionary trajectories
if evolution consists of change in allele frequency, what is speciation
lack of gene flow
what are the two forms of reproductive barriers
prezygotic and posyzygotic
what is a prezygotic RI
dont meet, dont mate, or mate but it doesn’t fertilize
what is postzygotic RI
reduced hybrid fitness
what are the speciation concepts
morphospecies species concept
phylogenetic species concept
biological species concept
what is the morphospecies species concept and pros and cons
species defined by unique morphological characteristics
pros: simple, applies to extinct and asexual too
cons: no clear genetic/evolutionary justification (could be arbitrary)
what is the phylogenetic species concept and pros and cons
species= smallest (monophyletic) group thats defended from a common ancestor that possesses diagnosable traits (genetic or morphological)
pros: testable, quantifiable, even works for asexuals
Cons: phylogenies are just estimates. Also any trait unique to a population however trivial defines them as a distinct species
what is biological species concept and pros and cons
species are groups of (potentially) interbreeding natural populations
pros: simple
cons: only applies to extant sexual species, also populations can live in different places and still be able to interbreed (Liger)
what are the types of geography of speciation
allopatric, peripatric, parapatric, symoatric
what is allopatric mean
geolographical barrier
what does peripatric mean
peripheral population with founder effect
what does parapatric mean
continuous population
coexist in same habitat but have distinct niches
what does sympatric mean
no geographical separation
occupy same niche
what is a cryptic species
2 or more species who were classified as a single species based on morphological similarities
what is by-product selection
indirect natural selection leading to RI
explain the two types of indirect natural selection
prezygotic: by-product selection
postzygotic selection: results from selection and adaptations to different niches
what is direct natural selection also known as and explain it
reinforcement
which is when natural selection leading to prezygotic isolation as a result of reduced hybrid fitness
what evolves faster prezygotic RI or postzygotic RI
prezygotic
under what type of geographical speciation does prezygotoc isolation evolve faster
why
faster in sympatry than allopatry
since more possibility to make a mistake (making hybrid) there will be stronger selection to not (since populations mix under sympatry)
what are the two types of sexual selection and explain them
environment specific: different sexual selection arises due to changes in environment
environment independent: sexual selection arises from interactions between sexes, independent of environment
what s the Bateson - Dobzhansky - Muller model
- population split in two
- selection selects for different genotype in at least one of the populations
- populations reconnect resulting in hybrids
shows evolution of genetic incompatibilities
is speciation due to BDMs environment dependent or independent
can be either
what is mutation oder speciation
when speciation is driven by BDMs incompatibilities driven by natural selection
