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Phylogenies and adapative radiation
Terms in this set (28)
Molecular phylogenies are useful when inferring relationships at ? levels
but we must be carful when using ?
deep taxonomic levels
using a small number of genes
other than revealing evolutionary relationships and time divergence what can phylogenies tell us about?
differential success, imbalance of tree etc
Phylogenetic distances often correlates with ?
mtDNA is very good because?
it is very abundant in the cell (high copy number)
why cam mtDNA analysis often lead to misleading relationships?
there is a mitochondrial-nuclear discordance
mtDNA essentially acts as a single acts
What is incomplete lineage sorting?
multiple lineages present in an ancestor become 'randomly' fixed in the descendants
- any one locus within a dat set could show a different phylogeny to the next
- thus not all single gene sequences reflect the true species are phylogeny
- should always back up mtDNA data
Incomplete lineage sorting simply means that multiple ___________ copies of genes can persist in descendant populations, and thus lead to the wrong ___________ interpretation
As always, some clades make it, others do not, this leads to ?
imbalance in the tree of life
Real trees are more imbalanced that they are?
expected by chance
natural selection will be operating at the _______ level, __________ level, and __________ level
natural selection also operates at the ?
Species selection describes differences in rates of ?
speciation and or extinction among lineages often in relation to species traits
We may see evidence of species selection on traits irrespective of any evidence at the ?
species with large body size are less likely to go extinct than small bodies creatures.
lagre bodies species just as likely to go extinct as small bodies ones but, they are more likely to speciate
African Cichlid fishes, radiate in many lakes across Africa
some radiation very small, most are in the _______ species region
there are some lakes where?
what does this system, allow you to test?
radiations haven't taken place
what it is about the fish that have radiated when they have
In Wagner et al., 2012
- it was found that egg dummies (relate to sexual selection) and lake conditions were both good predictors of radiation occurrence
what did this study suggest might predict how much speciation might take place?
extrinsic and intrinsic factors
What is Historical contingency?
more closely related species share evolutionary history by default
more closely related specie stand to be similar in their phenotypes
Because of their (evolutionary), these lineages are constrained to particular traits for example?
set of niches, body size, body shape, reproductive strategies
species tips, tend to be more __________ similar or __________ similar
those at the tips of tree should be engaging in ?
the strongest competition
what are two main ways of structuring a community?
what is habitat filtering?
what does this restrict?
loss of species fundamentally maladapted to a habitat (ecological sorting)
large numbers of species in clades
what is competition-driven structuring?
ecological differences avoid competitive exclusion allowing coexistence of populations
e.e.g the most phylogenetically distinct tend to coexist most effectively
In Violle et al., 2011
what experiment was done?
what was tested?
what was found?
Pairwise experiments with bacteivorous protist species
how often competition exclusion took place
- then mapped onto a phylogeny
those distantly related tended not to exclude on another
those who were closely related needed to exclude each other more
Habitat filtering - should ensure that relatively closely related species are occupying the same habitat relative to the other habitat
In competition-driven structuring - the most phylogenetically close taxa should be the ones with that experience the greatest competition
this produces ?
phylogenetic over dispersion
Why might there be the pull to the present?
1. A real increase in speciation rate towards present
2. A real decrease in extinction rate towards present
3. A constant background extinction rate, though the rate is lower than the formation of new species
Lineages through time plots and other phylogenetic analyses that start to infer about ecological processes e..g extinction, speciation should?
be viewed with caution
Phylogenies ar very good at telling us evolutionary relationships of ?
extant species and their populations within
THIS SET IS OFTEN IN FOLDERS WITH...
Adaptation in the wild: ecological traits
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