Chapter 26 Phylogeny

Phylogeny

evolutionary history of an organisms; where things originated; ancestry

Biodiversity

All of the diversity/variety of life on Earth

Systematics

study of evolutionary relationships between organisms

Taxonomy

Science of naming organisms

Taxon

a named group of organisms

Classification

assigning organisms to meaningful, hierarchical groups

Homology

Phenotypic and genetic similarities due to shared ancestry

Analogy

Phenotypic and genetic similarities due to convergent evolution

Convergent evolution

When similar environmental pressures and natural selection produce similar adaptations in organisms found in different evolutionary lineages

Divergent evolution

Species sharing a common ancestor become more distinct due to a differential selection pressure which gradual leads to speciation

Homologous structures

similar physical features in organisms that share a common ancestor, but the features serve completely different functions

Cladistics

A systematic approach using common ancestry as the primary criteria for classifying organisms

Monophyletic

Ancestral species and all its descendants

Paraphyletic

Ancestral species and some of its descendants

Polyphyletic

Includes distinct related species but not the common ancestor

Apomorphy/Autapomorphy

A specialized trait/character that is unique to a group or species; changed from initial ancestor to something different overtime

Plesiomorphy

An ancestral or primitive character state; present in an ancestor

Synapomorphy

Share, derived characteristics

Symplesiomorphy

Shared and ancestral characteristics

Homoplasy

When 2 of the same characteristics show up randomly

Gene families

Groups of related genes within an organism's genome

Orthologous genes

Homology is the result of a speciation event and hence occurs between genes found in different species

Paralogous genes

Results from a gene duplication where multiple copies of genes have diverged from one another within species

Molecular clocks

Method of estimating the time required for a given amount of evolutionary change based on the observation that some regions of genomes evolve at constant rates

**phylogenetic tree**

used to depict the relationships of organisms

What do phylogenetic trees show

Organisms’ closest relatives, ancestors, and where some of their traits may have originated

**What are the components of a phylogenetic tree**

 branching lines that represent divergent evolution, it can be based on DNA, morphology, or biochemistry

What is binomial nomenclature

the scientific naming of organisms using a genus and species that is latin based

Why do we use binomial nomenclature

used to limit confusion when studying organisms due to many having multiple common names

Who introduced nomenclature

Carolus Linnaeus

What is the mnemonic used to remember taxonomic classifications

Dear- Domain

King- Kingdom

Phillip- Phylum

Came- Class

Over- Order

For- Family

Great- Genus

Sex- Species

Why do Linnaean classification and phylogenetics/systematics sometimes disagree

Organisms can look similar and be distantly related and vice versa, depending on what system you use is who the organism might be related to

What are the three domains of life

Archaea, Bacteria, and Eukarya

Who proposed the third domain

Carl Woese

Why was a third domain proposed

Due to Archaea and Bacteria having too much diversity between each other to be grouped together