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Ecology and Speciation
Terms in this set (28)
Low levels of __________ is something that characterises species diversity in the real world
What is involved with the initial spread of divergence at individual loci through the rest of the genome?
What is the first step to the genie model of speciation?
An ecoloigcal barrier forming between 2 genomes/chromosomes of 2 different individuals
some isolation at the edge of a large habitats e.g. an isolated pol
- migration is mostly prevented between the two habitats
suggests no peripheral isolation but a cline of ecologies and a divergence along the cline
e.g. different species at each end, hybrids in the middle
What type of reproductive isolation are there?
Prezygotic reproductive isolation
Postzygotic reproductive isolation
What kinds of prezygotic isolation are there?
Mating decisions i.e. sexual selection/mate choice
Intrinsic traits of species and environment (e.g. habitat discontinuities)
e.g. non conductive for broadcast spawners
Prevent gene flow between populations
What kinds of postzygotic isolation are there?
How might a postzygotic isolation occur very quickly?
polyploid hybrid produced by two diploid mating together (plant) to produce a hybrid that reproduced on its own without the parental form
- i.e. chromosomal incompatibilities evolving
Based on studies on the 'tempo of hybrid inviability' which kind of reproductive isolation is morel likely ?
If prezygotic isolation is usually the mechanism then what it is likely to drive speciation?
i.e. those that usually involve an ecological factor in the divergence
What is the key point of ecological speciation?
that a trait associated with ecology becomes linked with mate preference
what is the starting point of ecological speciation?
what does this convey?
a polymorphism develops within a population (could be variation along a cline or a true polymorphism)
different ecological preference
When would it be easiest for mate preference and an ecological trait to become genetically linked?
if they are both associated with a pleiotropic gene
or if their genes are very close together on the genome
What would be a good way to test for reproductive isolation?
Perform a mating preference trial in the lab
Who performed a mating preference trial in the lab to confirm reproductive isolation?
Nosil et al., 2002
Rhagoletis pomonella - what is it?
what does the native form (North USA) live on?
the apple maggot fly
what was the problem with Linn et al., 2003 study?
30% of the individuals (Rhagoletis pomonella) made it to the wrong plants.
this would be enough to breakdown reproductive isolation
Who tested apple maggot flies on different different blends of apple or hawthorn juice?
Linn et al., 2003
why might there be linkage between the ecological preference of host fruit and timing of reproduction in Rhagoletis pomonella?
because the host fruit are available at different times of year
this can provide reproductive isolation
What is a magic gene or trait
a gene that is responsible for ecological divergence and reproductive divergence at the same time
What is a collection of genes or one gene that are responsible for both ecological divergence (e.g. ecological preference) and reproductive isolation (different e.g. phenology) called?
magic genes or magic traits
How are the Lord Howe palms reproductively isolated?
How was this found?
They flower ca. 6 weeks apart
- through prezygotic isolation
Through fieldwork on flowering time
How do the Lord Howe palms have different ecological preference?
Different habitat use
one mainly living on alkaline cancerous soil
other mainly on acidic soils
How is are the Lord Howe Palms said to have magic traits
The same gene(s) that determine their soil type preferences also determine their flowering time.
How long ago did the Lorde Howe Palms diverge?
about 2 million years ago
The 2 endemic Lorde Howe Palms are each others' ________ ________
When does the Van Doorn et al., 2009 model of ecological speciation fail to produce new species?
when individuals of intermediate phenotype are reasonably fit
THIS SET IS OFTEN IN FOLDERS WITH...
Adaptation in the wild: ecological traits
Adaptation in the wild: sensory ecology
Functional genes and adaptive evolution
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