Lab 2: Origin of Species Flashcards
What does a branch represent in a phylogenetic tree?
it represents a speciation event
What are character states?
they are morphological properties of an animal
what is a clade?
a set of species with the same common ancestor
what is gene flow?
its a mechanism of evolution involving transfer of alleles or genes from one population to another (i.e. if a part of the population moves away or migrates)
what is genetic drift?
It is another mechanism of evolution involving decrease in genetic diversity in populations. It is common after a population bottle necks or founder effects.
what is a genotype?
its the genetic traits of an individual
what is the molecular clock hypothesis?
it is figuring out when a species diverged from its ancestors by looking at the rate of mutation occurring (i.e. looking at strata and seeing the time periods between a fossil of the same species and seeing what changed). By looking at the continuous accumulation of mutations, we can use them to estimate how long ago the ancestors of currently living species split into different lineages.
what is the most recent common ancestor of a species?
it is usually a species that looks similar to the new one but has some changes
what is natural selection?
it is the process of evolution by which the organisms that are better adapted to their environment tend to reproduce and be more fit and survive
what is a node?
it is a branch point in a phylogenetic tree that represents an area of speciation
what is an outgrip?
it is a group similar to the species being observed but different (it evolved from the same common ancestor)
what is a phenotype?
a phenotype is genetic expression through how an individual LOOKS
what is a phylogenetic tree?
a phylogenetic tree is mapping relatedness among species and it is a hypothesis
what is a single-base substitution?
when one nucleotide base replaces another aka frameshift substitutions when one base replaces another
what is speciation?
when a new species is formed as a result of branching out from its common ancestor
what is a phylogeny/phylogenetics?
it is using complex algorithms to reconstruct evolutionary relationships among groups of organisms using molecular (DNA) or morphological (looks) data
what are species?
organisms that are formed as a result of speciation
what is a taxa?
a taxa is a taxonomic group of any rank, such as species, class or family
how often does a single-base substitution mutation occur?
it occurs 1 time for every half billion bases copied
How do we know how fast a particular DNA sequence is changing?
the fossil record tells us divergence times, providing a calibration point.
- finding a fossil of ancestral species for your phylogenetic tree can be helpful to base the mutations from afterwards, and you can assign a rate of mutation and make a phylogenetic tree from it
Discuss how you could use the necklaces to construct a reasonable approximation of the group’s history, including divergence times. how many necklaces could you compare at once?
you could compare 2 necklaces at once and see where most of the mutation lies and then base the rest off of the mutations there
