Phylogeny Flashcards
Phylogeny
Evolutionary history of a species or group of related species
Systematics
Classifying organisms and determining their evolutionary relationships (using fossil, molecular, and genetic data)
Carolus Linnaeus
Published a system of taxonomy based on resemblances; two features we use today are two part names and hiearchical classification
Two-Part name
Panthera pardus
Phylogenetic trees
Depict evolutionary relationships via branching
Branch point
Represents the divergence of two species
Sister taxa
Groups that share an immediate common ancestor
Basal taxon
A lineage that has no branches that diverted from it
How does DNA play a role in phylogeny?
Organisms with similar morphologies or DNA sequences are likely to be more closely related than organisms with different structures or sequences
Homology
Similarity due to shared ancestry (sister taxa or same branch)
Analogy
Similar to convergent evolution (cactus in America vs similar plant in Africa)
Convergent evolution
Similar environment produces similar (analogous) adaptations in organisms from different evolutionary lineages
Cladistics
Groups organisms by common descent
Clade
A group of species that includes an ancestral species and all its descendants
Monophyleyic clade
Consists of the ancestor species and all its descendants (valid)
Paraphyletic clade
Consists of an ancestral species and some, but not all, of its descendants (less)
Polyphyletic clade
Includes distantly related species but does not include their most recent common ancestor (more than necessary)
Shared ancestral character
A character that originated in an ancestor of the taxon (comparing to a singular group)
Shared derived character
An evolutionary novelty unique to a particular clade (a group comparison)
What is an example of a shared ancestral character?
Hinged jaws are a shared ancestral character for leopards
What is an example of a shared derived character?
Hinged jaws are a shared derived character for salamander, turtle, and leopard
A character can be both ancestral and derived, depending on context? T or F?
T
Outgroup
A species or group of species closely related to ingroup, the various species being studied; ingroup is compared w/ outgroup to differentiate between shared derived and shared ancestral characteristics
Ingroup
Various species being studied
Horizontal gene transfer
Movement of genes from one genome to another (between organisms in different domains
Example of horizontal gene transfer
Eukaryotic cell absorbs prokaryotic cyanobacterium and that prokaryotic cell has its own DNA and can act on its own. They are then passed down to other eukaryotic cells are reproduction. Mitochondria and chloroplasts are examples of this.
This West Indian manatee (Trichechus manatus) is an aquatic animal. Like amphibians and reptiles, mammals are tetrapods (vertebrates with four limbs). Predict why manatees are considered tetrapods even though they lack hind limbs, and suggest traits with manatees likely share with leopards and other mammals.
They are considered tetrapods despite lacking hind limbs because their common ancestor were belonging to the family of tetrapod; they likely share jaws and skeletal structure (homologous traits)
What is the hierarchy of taxonomic groups?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
