Taxonomy & Phylogeny
description
Transcript of Taxonomy & Phylogeny
![Page 1: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/1.jpg)
Taxonomy & Phylogeny
Classification of Organisms
![Page 2: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/2.jpg)
Classification• What characters are
suitable for classification
• Systematics– Combination of
taxonomy & phylogeny
– Systematic approach to understanding evolutionary relationships among organisms
![Page 3: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/3.jpg)
Hierarchical Classification System
• Taxa– Major groupings or categories– Nested set of increasing inclusiveness
Domain Kingdom
PhylumClass Order
Family Genus Species
![Page 4: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/4.jpg)
Cladistic Tree of Life
![Page 5: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/5.jpg)
![Page 6: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/6.jpg)
Wittiker’s 5 Kingdom Classification Scheme
![Page 7: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/7.jpg)
![Page 8: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/8.jpg)
![Page 9: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/9.jpg)
Taxonomic Rules
• Binomial nomeclature– Genus species– Genus name is noun– species name is adjective– Higher taxonomic levels (families, orders, etc..) are
also nouns
![Page 10: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/10.jpg)
Taxonomy Relates to Phylogeny
• Taxonomic characters allow phylogenetic grouping
• Useful taxonomic characters– Morphological – Molecular (biochemical)
• Chromosomal• Proteins• DNA
• Homologies– Character similarities attributed to common ancestry
![Page 11: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/11.jpg)
Using Taxonomic Characters to Construct Phylogenies
• Ancestral character state– The form of the trait present in the most recent
common ancestor of the groups being considered• Derived character state
– The variant forms of the trait present in the members of the groups being considered
• Polarity– Relationship of character trait state to ancestral state
![Page 12: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/12.jpg)
Example of Polarity Determination
• Study group– Amniotes – animals with amniotic membrane around
developing embryo– Birds, Reptiles, Mammals
• Character being studied– Dentition – teeth
• Character states– Present– Absent
• Question: Is dentition a derived or ancestral trait for amniotes?
• Outgroup comparison– Phylogenetically close group, but non-amniote
![Page 13: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/13.jpg)
Example of Polarity Determination
teethteeth
teeth
no teeth
MammalsBirdsReptiles
Amniote
Amphibians&Fish
Non-Amniote
• Outgroup has teeth– therefore teeth are considered ancestral & be presumed to occur in most recent
common ancestor of amniotes and non-amniotes• Teeth in amniotes is an ancestral character state• Loss of teeth in birds is a derived state
teethCommon Ancestor
![Page 14: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/14.jpg)
Cladograms
• Clade– Groups of organisms that share derived character
states• Synapomorphy
– Shared, derived character • Cladogram
– Nested, hierarchical assembly and representation of clades
![Page 15: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/15.jpg)
Phylogenetic Relationships Established by Comparison of Multiple Characters
![Page 16: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/16.jpg)
![Page 17: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/17.jpg)
Cladograms vs Phylogenetic Trees
• Cladogram– Lacks information
• duration of lineages• Amounts of evolutionary change
• Phylogenetic tree– Establishes extinct vs extant lineages– Indicates evolutionary timescale & degrees of
change• Length of lines or numerical indications
![Page 18: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/18.jpg)
Molecular PhylogenyHuman
• Comparison of cytochrome c mutations
![Page 19: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/19.jpg)
Phylogenetic Groupings
• Monophyletic– All descendents and most recent common ancestor
• Paraphyletic– Leaves out some descendents from a recent common ancestor
• Polyphyletic– Arbitrary groupings which do not include common ancestors
![Page 20: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/20.jpg)
![Page 21: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/21.jpg)
![Page 22: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/22.jpg)
![Page 23: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/23.jpg)
Cladistics & Cladograms vs Traditional Taxonomy
• Cladistics– Taxonomic groupings based solely on establishing
monophyletic relationships– Cladograms establish monophyletic taxonomic levels
• Traditional taxonomy– Common descent – phyletic relationship– Adaptive evolutionary change – ecological zones
![Page 24: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/24.jpg)
Fig. 32.7
![Page 25: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/25.jpg)
![Page 26: Taxonomy & Phylogeny](https://reader033.fdocuments.in/reader033/viewer/2022061409/56815d11550346895dcb12aa/html5/thumbnails/26.jpg)