The document summarizes the evolution of insects over 400 million years based on the fossil record, from the Ordovician period to the Triassic period. Early insect fossils from the Ordovician period were small in size. By the Carboniferous period, insects had already diversified greatly but their fossils remain incomplete. Some insect groups from this time, such as Meganisoptera, were very large while others were similar in size to modern insects. The Permian period saw the emergence of the first holometabolous insects. Many modern insect orders appeared by the Triassic period, though the fossil record remains imperfect.

3. 400 million (400.000.000) years

5. BUG SCHOOL
Episode 2

6. Bug School Ep. 2

7. Before we begin!
• This presentation uses copyrighted
photos and illustrations; which I am
allowed to do under the “fair use law” –
which allows me to use these images in a
transformative and educational way. This
video is demonetised and I gain nothing
from this; and for non-commercial
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8. Ordovician period (480 millionyears ago)

9. Rhyniognathahirsti

10. Rhyniella praecursor

11. Strudielladevonica

12. • Problem:The “hexapodgap”
: weare missingfossilsfrom
thetimeinwhich insects
diversified!
• Fossil recordvery
incomplete

13. Delitzschala(Spilapteridae)

14. Palaeodictyoptera

17. By the time we start finding
fossils.. They already diversified!

18. Carboniferous

19. Blattodea(Roachoids)

20. Meganisoptera(“griffinflies”)

21. WHY WERE THEY SO BIG?

22. However..
NOT ALL OFTHEM
WERETHISLARGE!
SOMEOF THEMHAD
SIZESSIMILARTO
MODERNINSECTS.

23. Meganisopteranymph

24. Gerardus sp. (Archaeorthoptera) Monura sp. (Diplura)

25. Archaeognatha (jumping bristletails)

26. Order Syntonopterodea
(mayflies ancestor)
Archimylacris eggintoni
a Carboniferous stem-group
dictyopteran (‘roachoid’)

27. The Permian

28. SupercontinentPangea

29. Mecoptera (pic. Mesopsychidae) Coleopterans (pic: Tshecardocoleidae)
Psocoptera (pic.Booklice) Neuroptera (pic: Permithonidae)

30. The first holometabola

31. • Hemimetabolism
• Holometabolism

32. Hemimetabolous
H
Holometabolous

33. Mecoptera (pic.Mesopsychidae) Coleopterans (pic: Tshecardocoleidae)
Psocoptera (pic.Booklice) Neuroptera (pic: Permithonidae)

40. Triassic

44. Hymenoptera (Xyelidae) Diptera(Anisopodidae)
Hemiptera (Cixiidae) Orthoptera (Locustavidae)
Thysanoptera (thrips)

45. Italophlebiagervasutti (Odotonata)
Blattodea: Phyloblattidae

48. Carabidae Elateroidea
Hydrophilidae Staphylinidae Byrrhidae
Cupedidae

51. To be continued..

54. Congratulationsstudent!