phylogeography Flashcards
what is phylogeography
comparing the evolutionary relationships of genetic lineages to their geographical distribution to try to understand which factors have most influenced their current distributions
what is biogeography
investigating the current distribution patterns of a species
reasons for studying phlogeography / biogeography
- understand how current biodiversity has evolved
- help predict responses to future environmental change
- species ID for cryptic species
- help identify taxonomic units both within and between species
what is a haplotype or haploid genotype
a group of alleles that are inherited from one parent
a different version of that gene
what is a haplotype networks
widely used approach for analysing and visualising the relationships among DNA sequences within a population or species
what is the role of phylogenetics
infer evolutionary relationships between groups (species, individuals, genes)
is a cladogram an evolutionary tree
no
what do cladograms assume
a current relationship rather than an ancestral one
what is the focus of a phylogram
evolutionary relationships
what do the branch lenghts represent in a phylogram
evolutionary distance
what does the ‘multi species coalescent’ mean
there are always multiple lineages and dead ends to phylograms that aren’t always shown on the trees
what kind of species can be found either side of the Isthmus of Panama and why
species pairs
was not always impassable, now is a barrier to gene flow = allopatric speciation
what species would of experienced a reduction in gene flow first during the formation of the Isthmus of Panama
deep-floor sea species
explain the idea of ‘molecular clocks’
concept that mutations in a genetic sequence occur at regular intervals
what is the molecular clock of mitochondrial markers
2% divergence every million years
what effect do mutations in the third base of a codon have
often little effect as they usually code for the same amino acid
explain the Bengula Upwelling system, what was it, what problem did it cause and who was affected
cold upwelling system in place for 2 million years
barrier to dispersal for many species due to abiotic (temperature) and biotic barrier
mostly problematic for coastal species, not an issue for oceanic species that can swim around it
how is ancient DNA often preserved before it is discovered
in permafrost
