BIO 370 Lecture Notes - Lecture 29: Horizontal Gene Transfer, Complex Differential Form, Sexual Reproduction
Phylogeny and Evolutionary History
• Evolution - the process by which different kinds of living organisms are thought to have
developed and diversified from earlier forms during the history of the earth.
• the gradual development of something, especially from a simple to a more complex
form.
• Evolution is change in the heritable characteristics of biological populations over
successive generations.
Phylogenies Reflect Evolutionary History
Phylogeny is the branching pattern of relatedness among populations as they give rise to
multiple descendant populations over evolutionary time.
Just as diversification of copies of
alleles can be represented by a branching diagram, so can diversification of organisms,
populations, species, and other operational taxonomic units (OTUs).
A phlogeeti tree is a rooted or urooted rahig diagra represetig historial
relationships among Operational Taxonomic Units (OTUs).
Phylogeny is the branching pattern of relatedness among populations* as they give rise to
multiple descendant populations* over evolutionary time.
Looking at the next three slides, what can you tell me about the scale at which phylogenies can
be used?
*We are going to examine exactly what populations are later when we revisit the species
concept. Right now, a population consists of closely related individuals.
OTU’s might be major groups of life (e.g., Orders to Kingdomes)
OTU’s ight e failies, orders, genera.
OTU’s ight e idividuals, populatios or speies.
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These are isolates of Micobacterium tuberculosis from human patients.
Phylogenetic trees fail to accurately describe reticulating (not simple branches) events
• Sexual reproduction
• Hybridization
• Horizontal gene transfer
What kinds of traits are used for studying phylogeny?
Any heritable traits
What kinds of traits are used for studying phylogeny?
Any that are heritable can be studied with a phylogenetic tree.
-- Heritable traits can be used to create a phylogenetic tree,
-- or they can be mapped onto
a phylogenetic tree
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A simple, logical, multi-step process
Reading Phylogenetic Trees
Whether a phylogeny is represented as a tree or ladder, one can rotate at any node o any
combination of nodes without changing the evolutionary relationships depicted in the tree.
What do the interior nodes represent?
A way to count number of changes, not reconstruction of ancestral types.
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Document Summary
Phylogeny is the branching pattern of relatedness among populations as they give rise to multiple descendant populations over evolutionary time. Just as diversification of copies of alleles can be represented by a branching diagram, so can diversification of organisms, populations, species, and other operational taxonomic units (otus). A ph(cid:455)loge(cid:374)eti(cid:272) tree is a (cid:862)rooted(cid:863) or (cid:862)u(cid:374)rooted(cid:863) (cid:271)ra(cid:374)(cid:272)hi(cid:374)g diagra(cid:373) represe(cid:374)ti(cid:374)g histori(cid:272)al relationships among operational taxonomic units (otus). Phylogeny is the branching pattern of relatedness among populations* as they give rise to multiple descendant populations* over evolutionary time. *we are going to examine exactly what populations are later when we revisit the species concept. Right now, a population consists of closely related individuals. Otu"s might be major groups of life (e. g. , orders to kingdomes) These are isolates of micobacterium tuberculosis from human patients. Phylogenetic trees fail to accurately describe reticulating (not simple branches) events: sexual reproduction, hybridization, horizontal gene transfer. Any that are heritable can be studied with a phylogenetic tree.
