Insect Phylogeny and Evolution. Determining Phylogenetic Relationships No engine, two wheels No...
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Transcript of Insect Phylogeny and Evolution. Determining Phylogenetic Relationships No engine, two wheels No...
Insect Phylogeny and Evolution
Determining Phylogenetic Relationships
No engine, two wheels
No engine, one wheel
Gas engine, two wheels
Diesel engine, four wheels, solid box on back
Gas engine, four wheels, glassed box on back
Gas engine, four wheels, no box on back
Gas engine, four wheels, solid box on back
Determining Phylogenetic Relationships
No engine, two wheels
No engine, one wheel
Gas engine, two wheels
Diesel engine, four wheels, solid box on back
Gas engine, four wheels, glassed box on back
Gas engine, four wheels, no box on back
No engine Engine
Gas Diesel
4 wheels 2 wheels
Box No box
1 wheel2 wheels
Gas engine, four wheels, solid box on back
glass solid
bicy
cle
unic
ycle
SUV
van
sedan
mot
orcy
cletr
uck
Some ancestral vehicle (??)
Determining Phylogenetic Relationships
No engine Engine
Gas Diesel
4 wheels 2 wheels
Box No box
1 wheel2 wheels
glass solid
bicy
cle
unic
ycle
SUV
van
sedan
mot
orcy
cletr
uck
Some ancestral vehicle (??)
Species - 7
Genus - 6
Family - 5
Order - 4
Phylum - 2
A little bit about taxonomy, classification and phylogeny
Systematics - study of the diversity and relationships of organisms both now and in the past.
Phylogeny - The evolutionary development and history of a species or higher taxonomic grouping of organisms.
Taxonomy - classification, naming and description of taxa.
Methods of establishing phylogenies
Evolutionary systematics - use several fixed levels of a hierarchy, such as kingdom, phylum, class, order, and family.
Evolutionary systematicsPheneticsCladistics
Methods of establishing phylogenies
Phenetics (numerical taxonomy)
Evolutionary systematicsPheneticsCladistics
Robert R. Sokal
C.D. Michener
- based on taking lots of measurements on organisms & then using computer algorithms to assign relationships among them
Problems - ignored ancestral vs. derived characteristics
Methods of establishing phylogenies Evolutionary systematicsPheneticsCladistics
Cladistics - classifies species of organisms into hierarchical monophyletic groups (clades) - based on shared
derived characteristics (or characters)
Willi Hennige.g. Character #1 - present in species A, B, C
Character #2 - present in species A, B, but not C
Have 2 groups - A + B and C
Methods of establishing phylogenies Evolutionary systematicsPheneticsCladistics
Cladograms
Methods of establishing phylogenies Evolutionary systematicsPheneticsCladistics
EntognathaArchaeognatha
Zygentoma EphemeropteraOdonataPlecopteraEmbiodea ZorapteraDermapteraGrylloblattodea Mantophasmatodea
?
OrthopteraPhasmatodeaBlattariaIsoptera Mantodea Psocoptera PhthirapteraThysanopteraHemiptera
Coleoptera Rhaphidioptera MegalopteraNeuroptera HymenopteraMecoptera Siphonaptera Diptera StrepsipteraTrichoptera Lepidoptera
Methods of establishing phylogenies Evolutionary systematicsPheneticsCladistics
Some definitions
Apomorphy - derived state is a characteristic believed to arisen in a recent common ancestor or a recently evolved feature that appears only in a group of closely related species. The elytra of that all beetles have serve to separate them from all insects
Plesiomorphy -or ancestral character that is present at the base of the tree. For example, the presence of six legs (shared by all insects) can be hypothesized to have existed in some common insect ancestor.
Methods of establishing phylogenies Evolutionary systematicsPheneticsCladistics
Some more definitions
Monophyletic groups - contain ancestor and all descendant species
Paraphyletic groups - contain ancestor and some but not all descendant species
Polyphyletic groups - contain taxa from two or more different monophyletic groups
MONOPHYLETIC
PARTIAL CLASSIFICATION OF DIPTERA
PARAPHYLETIC
POLYPHYLETIC
Phylogeny of the Arthropoda
Onychophora
Tardigrada
Arachnidomorpha(≈Chelicerata)
Crustaceomorpha
Atelocerata
Marellomorpha †
These taxa are all subphyla of Arthropoda
Next slide
Annelid-like
ancestor
Arthropoda
Phylogeny of the Mandibulata
Crustacea
Chilopoda
Symphyla
Pauropoda
Diplopoda
Entognatha
Insecta
†
††
††
= terrestrial origin
Chelicerates (spiders, scorpions, mites etc.)
Mandibulata
Hexapoda
Atelocerata(possess trachea)
Non-Hexapod Mandibulates
Symphla Chilopoda - centipedes
Diplopoda- millipedes Pauropoda
Summary of features of non-hexapod mandibulates
Chilopoda 0.5 - 30 cm 15 - 177 15 - 177 3 pr
Pauropoda 0.05 - 0.2 cm 9-10 12 2 pr
Diplopoda < 5 cm < 200 <200 2 pr
Size # of pairs of legs # of segments # m.p.’s
Symphyla < 1.0 cm 14 14 3 pr
Hexapoda
Protura
Diplura
Collembola
Insecta
Archaeognatha
Thysanura
Pterygota
Entognatha
Relationships among Hexapoda
500 400 300 200 100 0
EntognathaArchaeognatha
Zygentoma EphemeropteraOdonataPlecopteraEmbiodea ZorapteraDermapteraGrylloblattodea Mantophasmatodea?
OrthopteraPhasmatodeaBlattariaIsoptera Mantodea Psocoptera PhthirapteraThysanopteraHemiptera
Coleoptera Rhaphidioptera MegalopteraNeuroptera HymenopteraMecoptera Siphonaptera Diptera StrepsipteraTrichoptera Lepidoptera
Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous
Holometabola
Neoptera
Insecta
Pterygota
Apterygotes
Paleoptera
Hemimetabolous
Holometabolous
Hexapoda
500 400 300 200 100 0
EntognathaArchaeognatha
Zygentoma EphemeropteraOdonataPlecopteraEmbiodea ZorapteraDermapteraGrylloblattodea Mantophasmatodea?
OrthopteraPhasmatodeaBlattariaIsoptera Mantodea Psocoptera PhthirapteraThysanopteraHemiptera
Coleoptera Rhaphidioptera MegalopteraNeuroptera HymenopteraMecoptera Siphonaptera Diptera StrepsipteraTrichoptera Lepidoptera
Silurian Devonian Carboniferous Permian Triassic Jurassic cretaceous
Vascular plants Seed plants
Holometabola
Neoptera
Insecta
Pterygota
Steps in arthropod evolution
1. Common ancestor - legless annelid- undifferentiated body
1
2. Paired bilateral appendages- development of somites, antennal
segments, and simple eyes (like Onychophora)
3. Early arthropod - better developed eyes and jointed legs
2
4
3
4. Reduction in appendages- cephalization-modification of first appendages
into mouthparts- development of three tagmata
What about the Onychophora (“velvet worms” )?
Annelid ArthropodCharacteristics Characteristics
Peripatus
-worm-like body -segmented legs(during embryogenesis)
-paired nephridia -open circulatory system
- hemocoel- trachea- oral appendages
Evolution of the Insects
1. Appearance of primitive wingless insects2. Development of wings
3. Development of wing flexion mechanisms
4. Development of metamorphosis
(Carpenter - 1953)Four stages in insect evolution