17.2 Classification Based on Evolutionary Relationships Organization of all that speciation!

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1 Organization of all that speciation! Patterns of evolution..

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3 Taxonomy gets an over haul! Using more than morphology! 3 domains, 6 kingdoms

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5 KEY CONCEPT Modern classification is based on evolutionary relationships. Called Systematics/Cladistics

6 Cladistics is classification based on common ancestry. Phylogeny is the evolutionary history for a group of species. evidence from living species, fossil record, and molecular data shown with branching tree diagrams

7 A cladogram is an evolutionary tree made using cladistics. A clade is a group of species that shares a common ancestor. Each species in a clade shares some traits with the ancestor. Each species in a clade has traits that have changed.

8 Plants? Bryophyte Tracheophyte Gymnosperm Angiosperm

9 Derived characters are traits shared in different degrees by clade members (synapomorphies). basis of arranging species in cladogram more closely related species share more derived characters represented on cladogram as hash marks on the x axis 1 Tetrapoda clade 2 Amniota clade 3 Reptilia clade 4 Diapsida clade FOUR LIMBS WITH DIGITS 5 Archosauria clade SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE EMBRYO PROTECTED BY AMNIOTIC FLUID FEATHERS & TOOTHLESS BEAKS. DERIVED CHARACTER

10 Nodes represent the most recent common ancestor of a clade. Clades can be identified by snipping a branch under a node. 1 Tetrapoda clade 2 Amniota clade 3 Reptilia clade CLADE 4 Diapsida clade 5 Archosauria clade SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE FEATHERS AND TOOTHLESS BEAKS. EMBRYO PROTECTED BY AMNIOTIC FLUID NODE FOUR LIMBS WITH DIGITS DERIVED CHARACTER

11 CLADE/MONOPHYLETIC TAXON: A group of organisms, that are derived from a common ancestor. EX: Birds and reptiles and the reptilian ancestor TAXON (TAXA): Group of organisms PARAPHYLETIC TAXON: A group of organisms that does not include all possibly related organisms. EX: Looking at just birds and then reptiles separately Out-group is the least related group on the far left!

12 Outcomes?

13 Steps to making a cladogram: 1. Determine the traits to assess in order of evolutionary complexity. 2. Create a table of who has the traits and who does not 3. Arrange the traits along the bottom of the diagram and the organisms coming off that line.(most advanced organism will be on the top right when done) 4. Determine common ancestry along the way to determine if new branch is needed or if one organism derives but does not have new ancestry.

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18 Anatomical tools Homologous structures (shared homology)-structure has same ancestry and anatomy, even though immediate function differs:

19 Vestigial- structure has huge function in one group, little or no function in another

20 Analogous structure (analogy)-structure has same immediate function but not ancestry or anatomy. Ex: bee wings and bird wings

21 Molecular clock- once divergence from a common ancestor occurs and each species lineage continues to evolve separately, DNA mutations can be compared to measure genetic differences between the group. Tend to use proteins that have plasticity without losing function. (Ex: not hemoglobin) Cytochrome C is better choice. EX: Species A has a 6% base pair difference in molecule from B, A and C have a 32% difference, who is more closely related? Why?