Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is...
-
date post
21-Dec-2015 -
Category
Documents
-
view
214 -
download
0
Transcript of Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is...
![Page 1: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/1.jpg)
Taxonomy
• To sort organisms into species• To classify species into higher taxonomic
levels• A taxon is a taxonomic unit at any level;
for example “Mammalia” is a taxon at the Class level (taxa = plural)
![Page 2: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/2.jpg)
Taxonomy
• Species that appear to be closely related are grouped into the same genus (e.g., the leopard Panthera pardus; African lion Panthera leo; Tiger Panthera tigris)
• Similar genus are grouped into the same family, and so on…
![Page 3: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/3.jpg)
Domain
Kingdom
Phylum
Subphylum
Class
Order
Family
Genus
Species
Diversification
![Page 4: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/4.jpg)
Taxonomy
• Classification system• Domain Eukarya• Kingdom Animalia• Phylum Chordata• Class Mammalia• Order Primates• Family Hominidae• Genus Homo• species sapiens
![Page 5: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/5.jpg)
Taxonomy
• The taxonomic system was developed by Linnaeus in the 1750’s
• Binomial (two part) system; Genus species• The scientific name includes the species
name• Example: Homo sapiens or H. sapiens• No 2 organisms can have the same scientific
name and this name is the same everywhere in the world!
![Page 6: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/6.jpg)
Taxonomy• Scientific names are descriptive
• May describe unique characteristic, region where species is found, etc.
• Example: Humpback whale Megaptera novaeangliae – Magas = large– Pteron = wing– Novas = new– Angaliae = England
![Page 7: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/7.jpg)
Taxonomy
• Common names can be deceiving…
http://www.koala.net/media http://www.ticam.utexas.edu/images/grizzly.jpg
“bear”
“dolphin”
![Page 8: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/8.jpg)
Taxonomy
• Scientific names may change over time
• Many hierarchies are being re-examined based on results of molecular analysis
• Linnaean taxonomy does not take into account evolutionary relationships
• Enter phylogeny and systematics…
![Page 9: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/9.jpg)
Systematics
• The reconstruction and study of evolutionary relationships
• Phylogeny – an evolutionary tree; species grouped by how long they’ve shared a common ancestor
• Evidence for determining these relationships must come from shared homolagous characteristics
![Page 10: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/10.jpg)
Phylogeny
• The evolutionary history of a group is presented graphically in phylogenetic trees
• In a phylogenetic tree:– Time goes from the bottom up– Read from bottom up, not left to right– Branch length = number of changes– Depicts evolutionary relationships!
![Page 11: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/11.jpg)
Time
![Page 12: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/12.jpg)
Time
![Page 13: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/13.jpg)
Remember: Read from the bottom up; not left to right!
![Page 14: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/14.jpg)
These three versions convey the same information (phylogenies depict evolutionary
relationships)
Node 1: common ancestor of human and chimp
Node 2: c.a. of human, chimp, and gorilla
![Page 15: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/15.jpg)
![Page 16: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/16.jpg)
Phylogenetic trees reflect hierarchical classification of taxonomic groups
![Page 17: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/17.jpg)
Phylogeny• Systematists prefer
monophyletic taxa
• Monophyletic – a single ancestor gave rise to all species in that taxon (and to no species in any other taxa); “single tribe”
• A monophyletic group consists of a common ancestor and all its descendants
![Page 18: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/18.jpg)
Monophyletic group
Monophyletic group (indicated in pink) consists of most recent common ancestor and all of its
descendents
Common ancestor: “Archosaur”
![Page 19: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/19.jpg)
Paraphyletic group
Paraphyletic group (indicated by pink) consists of the most recent common ancestor and some
(not all) of the descendents
1 descendent, the hawk, is excluded
![Page 20: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/20.jpg)
Polyphyletic group
Polyphyletic group (indicated in pink) does NOT contain the most recent common ancestor
Birds and bats can be included because of morphological similarities (convergent evolution)
![Page 21: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/21.jpg)
Monophyletic versus Paraphyletic and Polyphyletic groups
![Page 22: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/22.jpg)
Old classification system for plants
New classification system for plants
![Page 23: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/23.jpg)
Phylogeny
• What evidence is used to reconstruct phylogeny?– Comparative anatomy– Morphology– Embryology– Protein comparisons– DNA comparisons
• Problems of homology versus analogy
![Page 24: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/24.jpg)
Phylogeny• Homology (homologous structures) –
likeness due to common ancestor• Analogy (analogous structures) – also
known as “homoplasy”; likeness due to convergent evolution; functional constraint
• Analogous structures are the result of separate evolution
![Page 25: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/25.jpg)
![Page 26: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/26.jpg)
![Page 27: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/27.jpg)
Comparative Biology
Elongated canine teeth (saber teeth) evolved separately in different groups of carnivores
![Page 28: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/28.jpg)
Cladistics• Cladistics – only shared derived
characters are used in determining evolutionary relationships
• Homoplasy (analogy) complicates cladistic analysis
• Species that share a common ancestor constitute a clade (a monophyletic group is a clade)
• Clades are hypotheses, just as phylogenetic trees are
![Page 29: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/29.jpg)
Time
clade
![Page 30: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/30.jpg)
Cladistics
• Principle of parsimony – favors the hypothesis that requires the fewest assumptions (the phylogeny that requires the fewest evolutionary events is the best hypothesis)
• Simplest is best (Occam’s Razor)
![Page 31: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/31.jpg)
Parsimony and Homoplasy
Placement of frogs as closely related to salamanders requires that tail loss (in adults) evolved twice (homoplasy); if frogs are
closely related to gorillas, then tail loss evolved once, but would also have to lose amniotic membrane and hair
![Page 32: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/32.jpg)
![Page 33: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/33.jpg)
Ancestral versus Derived characters
• Ancestral – dates back to common ancestor (found in common ancestor and all its descendents)
• Derived – feature of distinct taxon• Hair is a shared derived feature of mammals, but
so is a backbone; the presence of a backbone cannot help us distinguish mammals from other vertebrates
• The presence of backbone is a shared ancestral feature (also present in amphibians and reptiles)
![Page 34: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/34.jpg)
![Page 35: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/35.jpg)
![Page 36: Taxonomy To sort organisms into species To classify species into higher taxonomic levels A taxon is a taxonomic unit at any level; for example “Mammalia”](https://reader036.fdocuments.us/reader036/viewer/2022062516/56649d5d5503460f94a3cbef/html5/thumbnails/36.jpg)
Recommended Reading
• Dictionary of Word Roots and Combining Forms; Donald J. Borror
• Best $15 you can spend
• Compiled from Greek, Latin and other languages, with special reference to biological terms and scientific names