1 / 19

Understanding Phylogenetic Trees: A Study of Lineage and Evolution

This pre-test addresses fundamental concepts of phylogenetic trees, including their structure and interpretation. It explores relationships between mammals, such as the genetic closeness of pigs to cows or camels, and identifies primitive species. Key elements include common ancestors, nodes, terminal taxa, and branches, with emphasis on reading tree nodes correctly. The text also highlights rules for constructing trees, notably bifurcation and monophyly rules, and discusses both phylograms and cladograms, along with the significance of timing in evolutionary events.

nevina
Télécharger la présentation

Understanding Phylogenetic Trees: A Study of Lineage and Evolution

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Understanding Trees

  2. Pre-test Which mammal is the pig more closely related to, cow or camel? Which mammal here is the most primitive? Fig. 4.8b

  3. Common ancestor • Root of the tree • Nodes • Terminal taxa (tips) • Branches

  4. Phylograms and Cladograms

  5. Trees can be built for extinct organisms…

  6. Trees can include lineage “persistence”

  7. Some trees show timing of events

  8. Most trees today are built for extant organisms only…

  9. Tree Rules 1. Read the nodes, remember they swivel 2. Bifurcation rule 3. Monophyly snip rule 4. Sibling ≠ Ancestor 5. Sister lineage snip rule and ages

  10. 1. Read the nodes, remember they swivel! Don’t read left to right or top to bottom Read the nodes, and the nodes swivel

  11. Read the nodes A B C D f e g For cladograms, some information about timing (e and f after g)

  12. For phylograms, a little more information about timing

  13. This tree is ladderized right…Swivel the nodes to make it ladderized leftRedraw it with lungfish at the top

  14. Assignment

  15. 2. Bifurcation Rule • Can only have one divergence event at a time. • Can’t have two divergence events at the same time (snap two fingers at once)

  16. Breaking the Bifurcation Rule:Hard polytomies and Soft polytomies Cichlids

More Related