Insect Phylogeny and Evolution

1
Insect Phylogeny and Evolution
2
Determining Phylogenetic Relationships
No engine, two wheels
Gas engine, two wheels
Gas engine, four wheels, no box on back
Diesel engine, four wheels, solid box on back
Gas engine, four wheels, glassed box on back
No engine, one wheel
Gas engine, four wheels, solid box on back
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Determining Phylogenetic Relationships
unicycle
motorcycle
bicycle
sedan
truck
SUV
van
No engine, two wheels
Gas engine, two wheels
solid
glass
Gas engine, four wheels, no box on back
Box
No box
Diesel engine, four wheels, solid box on back
4 wheels
2 wheels
1 wheel
2 wheels
Gas engine, four wheels, glassed box on back
Diesel
Gas
No engine, one wheel
No engine
Engine
Gas engine, four wheels, solid box on back
Some ancestral vehicle (??)
4
Determining Phylogenetic Relationships
motorcycle
unicycle
bicycle
sedan
truck
SUV
van
Species - 7
solid
glass
Genus - 6
Family - 5
Box
No box
Order - 4

Phylum - 2
4 wheels
2 wheels
Diesel
Gas
1 wheel
2 wheels
No engine
Engine
Some ancestral vehicle (??)
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Phylogeny of the Arthropoda
Onychophora
Tardigrada
Annelid-like ancestor
Marellomorpha
Arachnidomorpha(Chelicerata)
Crustaceomorpha
Next slide
Arthropoda
Atelocerata
These taxa are all subphyla of Arthropoda
6
Phylogeny of the Mandibulata
Chelicerates (spiders, scorpions, mites etc.)

terrestrial origin


Crustacea
Chilopoda
Symphyla
Pauropoda
Mandibulata
Diplopoda

Atelocerata

Entognatha
Hexapoda
Insecta
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Non-Hexapod Mandibulates
Chilopoda - centipedes
Symphla
Pauropoda
Diplopoda- millipedes
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Summary of features of non-hexapod mandibulates
Size of pairs of legs of segments m.p.s
Chilopoda 0.5 - 30 cm 15 - 177 15 - 177 3 pr
Symphyla lt 1.0 cm 14 14 3 pr
Pauropoda 0.05 - 0.2 cm 9-10 12 2 pr
Diplopoda lt 5 cm lt 200 lt200 2 pr
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Relationships among Hexapoda
Collembola
Entognatha
Protura
Diplura
Hexapoda
Archaeognatha
Insecta
Thysanura
Pterygota
10
500 400
300 200 100
0
Silurian
Devonian
Carboniferous
Permian
Triassic
Jurassic
Cretaceous
Entognatha
Archaeognatha
Zygentoma
Hexapoda
Ephemeroptera
Odonata
Insecta
Plecoptera
Embiodea
Pterygota
Zoraptera
Dermaptera
Grylloblattodea
?
Mantophasmatodea
Orthoptera
Phasmatodea
Blattaria
Isoptera
Mantodea
Neoptera
Psocoptera
Phthiraptera
Thysanoptera
Hemiptera
Coleoptera
Rhaphidioptera
Megaloptera
Neuroptera
Hymenoptera
Mecoptera
Holometabola
Siphonaptera
Diptera
Apterygotes
Strepsiptera
Trichoptera
Paleoptera
Lepidoptera
Hemimetabolous
Holometabolous
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500 400
300 200 100
0
Silurian
Devonian
Carboniferous
Permian
Triassic
Jurassic
cretaceous
Entognatha
Archaeognatha
Zygentoma
Ephemeroptera
Odonata
Insecta
Plecoptera
Embiodea
Pterygota
Zoraptera
Dermaptera
Grylloblattodea
?
Mantophasmatodea
Orthoptera
Phasmatodea
Blattaria
Isoptera
Mantodea
Neoptera
Psocoptera
Phthiraptera
Thysanoptera
Hemiptera
Coleoptera
Rhaphidioptera
Megaloptera
Neuroptera
Hymenoptera
Mecoptera
Holometabola
Siphonaptera
Diptera
Strepsiptera
Trichoptera
Lepidoptera
Vascular plants Seed plants
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Steps in arthropod evolution
1

• Common ancestor - legless annelid
• - undifferentiated body

2

• Paired bilateral appendages
• - development of somites, antennal segments, and
  simple eyes (like Onychophora

3
4
3. Early arthropod - better developed eyes and
jointed legs

• Reduction in appendages
• - cephalization
• -modification of first appendages into
  mouthparts
• - development of three tagmata

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What about the Onychophora ( velvet worms )?
Annelid Arthropod Characteristics Characterist
ics
-worm-like body -segmented legs (during
embryogenesis)
Peripatus
-paired nephridia -open circulatory system
- hemocoel
- trachea
- oral appendages
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Evolution of the Insects
(Carpenter - 1953) Four stages in insect evolution
4. Development of metamorphosis
3. Development of wing flexion mechanisms
2. Development of wings
1. Appearance of primitive wingless insects