Evolution- Phylogeny Flashcards Preview

Evolution, Ecology, and Biodiversity > Evolution- Phylogeny > Flashcards

Flashcards in Evolution- Phylogeny Deck (21)
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What is systematics?

An analytical approach to understanding diversity and relationships of organisms both extant and extinct


What are the categories of classification?

Domain, kingdom, phylum, class, order, family, genus, and species


What is a taxon?

The taxonomic unit at any level


What is a phylogenetic tree?

A hypothesis about evolutionary relationships


What are sister taxa?

Groups that share an immediate ancestor


What is a polytomy?

A branch from which more than 2 groups emerge


What don't phylogenetic trees do?

They don't show patterns of descent and they don't indicate when species evolved or how much change has occurred


What is convergent evolution?

Similar environmental pressure and natural selection produce similar adaptation in organisms for different evolutionary lineages


What are non-homologous traits and what is another word for them?

Structures or molecular sequences that evolved independently. Another word is homoplasy


What is a cladogram?

A hypothesis depicting patterns of shared characters among taxa


What is a clade?

It is within a cladogram. It is a group of species that includes ancestral species and all its descendants


What does a paraphyletic group consist of?

An ancestral species and some, but not all, of the descendants


What does a polyphyletic group consist of?

Various species that lack a common ancestor


What is the difference between shared ancestral and shared derived characters?

Shared ancestral characters originate in an ancestor of a taxon. Shared derived characters is unique to a particular clade


What are the two things the length of a branch can represent in phylogenetic trees?

1. Reflect the number of genetic changes that have taken place in a particular DNA sequence in that lineage
2. Reflect chronological time


What are molecular clocks?

They uses constant rates of evolutions in some genes to estimate the absolute time of evolutionary genes


What are some difficulties with molecular clocks?

- Not as smooth as neutral theory predicts
- Some DNA changes are favoured over others
- Estimates of evolutionary divergences older than the fossil record have a high degree of uncertainty


What are the 3 domains?

Bacteria, Archaea, and Eukarya


What does the tree of life suggest and what is is based on?

Eukaryotes and Archaea are more closely related to each other. It is based largely on rRNA genes that have evolved slowly


Who is Doolittle?

First to show importance of horizontal gene transfer


What is horizontal gene transfer?

The movement of genes from one genome to another