Lecture 1 Flashcards
what is taxonomy? what is it based on?
-discipline of naming and categorizing organisms
-based on shared traits
what are examples of the traits that taxonomy revolves around?
-morphological traits
-developmental features/processes
-molecular
what are morphological traits?
-appearance
-internal structures
what is an example of how developmental features/processes can be used to compare organisms?
-life cycle of the organisms
what are molecular traits?
-gene/protein sequences
who were the levels of classification developed by?
-carolus linnaeus
what are the levels of classification from most broad > most specific?
-domain
-kingdom
-phylum
-class
-order
-family
-genus
-species
how does binomial scientific naming work?
-name formed from the genus + species
-latin names for consistency
-ex: homo sapiens
what is phylogeny?
-evolutionary history of a species or group of related species
what is systematics? what does it use?
-discipline that classifies organisms + determines their evolutionary relationships
-systematists use phylogenetic trees to relay information
what types of data are used within systematics to infer evolutionary relationships?
-morphological data (phenotypes)
-biochemical data (proteins (myoglobin proteins))
-genetic data (DNA sequences)
-fossils
what does a branch point on a phylogenetic tree represent? what is this event called?
-the divergence of 2 or more species from a common ancestor
-speciation event (produces 2 or more species)
what is an outgroup on a phylogenetic tree?
-a more distantly related group of organisms
-branches off the initial ancestor ONLY
-used as a reference
what is considered sister taxa on a phylogenetic tree?
-2 groups that share an immediate common ancestor
what is considered a polytomy on a phylogenetic tree?
-more than 2 groups that share an immediate common ancestor
what causes a polytomy?
-an unresolved level of divergence
what is a rooted phylogenetic tree?
-represents the last common ancestor to all taxon
what do phylogenies rely on? what are they due to?
-morphologies
-genes
-biochemistry of living organisms (chemical processes)
-due to homology, not analogy
when would a phylogeny need to be revised?
-when new info is gathered/discovered that could affect the current understanding
what are homologies?
-phenotypic and genetic similarities due to shared common ancestry
are evolutionary relationships present in homologies?
-YES
what are homologous structures?
-similar structure (not always obvious)
-same or different function
-derived from a common ancestor
what is analogy?
-similarities due to convergent evolution
what are analogous structures?
-different structure (not always obvious)
-similar function
-due to convergent evolution (no common ancestry)
what is a clade?
-a group of related species that includes an ancestral species + all of its descendants
-3 groupings
what are the 3 groupings?
-monophyletic
-paraphyletic
-polyphyletic
what is a monophyletic clade?
-contains the ancestral species and all of its descendants
what is a paraphyletic group?
-contains the ancestral species, but not all of its descendants
what is a polyphyletic group?
-contains distantly related species, but no common ancestor to all
what is a shared ancestral character?
-a character that originates in an ancestor
what is a shared derived character?
-a character that is novel to a specific clade
-not found in the ancestor
if a shared derived character is present, what can the ancestor be defined as?
-an outgroup
can a character be both ancestral and derived?
-yes, depending on context
what are genome sequencing projects?
-projects that determine the sequence of all DNA in an organism
what is needed for a genome sequencing project? how do they work?
-need computer programming and mathematical tools
-device called a nanopore sequencer
-algorithms score changes and then scores are compared
what are DNA barcoding projects?
-projects that take segments of DNA + DNA related molecules and use coding techniques to identify many species
what is the purpose of DNA barcoding projects?
-used against poachers (can detect from animal blood, hair, or meat)
-used to detect what animal attacked a human
what DNA + DNA related molecules are used in coding to trace evolutionary history?
-rRNA
-mtDNA
what is rRNA? how is it best used?
-ribosomal RNA
-changes + mutations are slower
-useful in investigating branch points far in the past
what is mtDNA? how is it best used?
-mitochondrial DNA
-changes + mutations are faster
-useful in exploring recent evolutionary events
what organisms are more likely to be closely related?
-organisms with similar morphologies or DNA sequences
how does cladistics group organisms?
-groups them by common descent
