1 / 26

Understanding Phylogeny and Systematics in Biology

Explore the classification hierarchy, evolutionary relationships, and tools used to develop phylogenetic trees. Dive into the three domains of life, DNA evidence, and the concept of parsimony. Engage in constructing phylogenetic trees and understanding the Tree of Life.

dnegron
Download Presentation

Understanding Phylogeny and Systematics in Biology

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. Chapter 26 Phylogeny and the Tree of Life

  2. What you need to know: • The taxonomic categories and how they indicate relatedness. • How systematics is used to develop phylogenetic trees. • The three domains of life including their similarities and their differences.

  3. Systematics: classifying organisms and determining their evolutionary relationships Taxonomy (classification) Systematics Phylogenetics (evolutionary history)

  4. Tools used to determine evolutionary relationships: • Fossils • Morphology (homologous structures) • Molecular evidence (DNA, amino acids) Who is more closely related? Animals and fungi are more closely related than either is to plants.

  5. Taxonomy: science of classifying and naming organisms • Binomial nomenclature (Genus species) Naming system developed by Carolus Linnaeus.

  6. REMEMBER!! • Dear King Philip Came Over For Good Spaghetti • Dear King Philip Crossed Over Five Great Seas • Dear King Philip Came Over From Germany Stoned • Your own???

  7. Phylogenetic Tree • Branching diagram that shows evolutionary history of a group of organisms

  8. Molecular Systematics • Hypothesizing phylogenies using molecular data • apply principle of parsimony • simplest explanation • fewest evolutionary events that explain data hypothetical bird species 3 possible phylogenies (there are more)

  9. Parsimony • Choose the “tree” that explains the data invoking the fewest number of evolutionary events

  10. Parsimony & analogy vs. homology Phylogenetic trees are hypotheses Which is the most parsimonious tree?

  11. Activity: Constructing a Cookie Phylogenetic Tree

  12. Living (extant) species Common ancestor (fossil)

  13. Extant species Common ancestor

  14. Example of a Cookie Tree

  15. Leopard Turtle Hair Salamander • Clade= group of species that includes an ancestral species + all descendents • Shared derived characteristics areused to construct cladograms Amniotic egg Tuna Four walking legs Lamprey Hinged jaws Lancelet (outgroup) Vertebral column Cladogram

  16. Monophyletic, paraphyletic, and polyphyletic groups Consists of an ancestral species and some of its descendants, But not all of them Some of its members have Different ancestros Consists of an ancestral species And all of its descendants

  17. Constructing a phylogenetic tree A 0 indicates a character is absent; a 1 indicates that a character is present.

  18. Branch lengths can represent genetic change

  19. Branch lengths can indicate time

  20. Draw a phylogenetic tree based on the data below. Draw hatch marks on the tree to indicate the origin(s) of each of the 6 characters.

  21. Answer:

  22. Various tree layouts Circular (rooted) tree Unrooted tree Rooted tree

  23. Principle of maximum parsimony: use simplest explanation (fewest DNA changes) for tree – “keep it simple” • Molecular clocks: some regions of DNA appear to evolve at constant rates • Estimate date of past evolutionary events • Eg. Origin of HIV infection in humans= 1930’s

  24. Tree of Life • 3 Domains: Bacteria, Archaea, Eukarya

  25. SYSTEMATICS focuses on phylogeny Biological diversity taxonomy cladistics classification Identification of species D K P C O F G S Homologous similarities fossils binomial molecular Genus, species morphology

More Related