Lesson 3 - Tree of Life Flashcards
how many genes in the genome of yeast have recognizable similarity to human genes
1/3
“probably all the organic beings which have ever lived on this earth have descended from some one primordial form”
idea of common descent
evolutionary history of a species or group of related species
phylogeny
classifies organisms and determines their evolutionary relationships
systematics
what do systematists use to infer evolutionary relationships
- fossil data
- molecular data
- genetic data
ordered division and naming of organisms
taxonomy
in 18th century, he published a system of taxonomy based on resemblances
Carolus Linnaeus
two-part scientific name
Genus species
the second element in the Latin binomial name of a species, which follows the generic name and distinguishes the species from others in the same genus
specific epithet
Linnaeus introduced a system for grouping species in __ __ __
increasingly broad categories
taxonomic groups from broad to narrow
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
taxonomic unit at any level of hierarchy
taxon
how do systematist depict evolutionary relationships
in branching phylogenetic trees
recognizes only groups that include a common ancestor and all its descendants
PhyloCode
represents a hypothesis about evolutionary relationships
phylogenetic tree
represents the divergence of two species
branch point/ node
groups that share an immediate common ancestor
sister taxa
includes a branch to represent the last common ancestor of all taxa in the tree
rooted tree
is a branch from which more than two gruops emerge
polytomy
what do phylogenetic trees show
patterns of descent
what do phylogenetic tree not indicate
- when species evolved
- how much genetic change occured in a lineage
provide important information about similar characteristics in closely related species
phylogeny
where are phylogenies inferred from
morphological and molecular data
organisms with similar morphologies or DNA sequences are likely to be __ __ __ than organisms with different structures or sequences
more closely related
similarity due to shared ancestry
homology
similarity due to convergent evolution
analogy
homology is due to
shared ancestry
analogy is due to
convergent evolution
occurs when similar environmental pressures and natural selection produce similar/ analogous adaptations in organisms from different evolutionary lineages
convergent evolution
development of organs or other bodily structures within different species, which resemble each other and have the same functions, but did not have a common ancestral origi
homoplasies
how can homology be distinguished from analogy
comparing
- fossil evidence
- degree of complexity
the more complex two similar structures are, the more likely it is that they are __
homologous
uses DNA an other molecular data to determine evolutionary relationships
molecular systematics
evolutionary change of features within a sinle lineage (species)
anagenesis
branching of lineage into two or more descendant lineages
cladogenesis
descendants become more different from each other
divergence/ divergent evolution
segement in tree which may split at an internal branch point or node
lineage/ branch
group of species that includes an ancestral species and all its descendants
clade/ monophyletic group
two clades that originate from a common ancestor
sister groups
root of the tree
most recent common ancestor (MRCA)
grouping consists of an ancestral species and SOME of its descendants
paraphyletic group
grouping consists of various species that LACK a common ancestor
polyphyletic group
character that originated in an ancestor of the taxon
shared ancestral character
- plesiomorphy
an evolutionary novelty unique to a particular clade
shared derived character
- apomorphy
two types of apomorphy
- autapomorphy
- synapomorphy
trait found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to the focal taxon
autapomorphy
derived trait shared by two or more groups
synapomorphy
assumes that the tree that requires the fewest evolutionary events is the most likely
maximum parsimony
states that, given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events
principle of maximum likelihood
predicts features of an ancestor from features of its descendants
phylogenetic bracketing
lineages become modified from different ways of life
adaptive radiation
- two or more species affect each other’s evolution
- caused by symbiotic relatinships and predator-prey dynamics
coevolution
valuable tool for tracing organisms’ evolutionary history
comparing nucleic acids or other molecules
changes relatively slowly and is useful for investigating branching points hundreds of millions of years ago
DNA that codes for rRNA
evolves rapidly and can be used to explore recent evolutionary events
mtDNA (mitochondrial DNA)
inceases the number of genes in the genome, providing more opportunities for evolutionary changes
gene duplication
- found in a single copy in the genome and are homologous between species
- Genes separated by speciation
orthologous genes
- found in more than one copy in the genome
- resulted from gene duplication
- can divege within the clade that carries them and often evolve new functions
paralogous genes
paralogous genes can diverge within the clade that carries them and often evolve __ __
new functions
loci in different species that descended from the same locus
orthologous
loci in the same species or different species that descended from ancestral species
paralogous
branching tree that portrays the history of DNA sequences of a gene
gene tree/ gene genealogy
group of genes within an organism that was inherited together from a single parent
haplotype
