Lecture 4 Flashcards
Evolution and Natural Selection
change in gene frequency in population driven by natural selection.
Natural selection factors in environment that cause survival and reproduction differences, more favorable traits
Natural Selection Processes
Disease, harsh environment, competition (for anything), predation, parasitism
Artificial Selection Processes
Insecticides, Habitat Destruction, and global warming
Basically human made (ex. peppered moth turned darker due to industrial revolution)
Good ones= breeding, biocontrol
Insect Evolution
Strong fossil record. Compression fossils. Collembola: Springtails.
Evolution in Wings
Class Insecta
Subclass- Apterygota (no wings), Pterygota (wings)
Infraclass (pterygota)- Paleoptera (non-folding like dragonfly) and Neoptera (folding)
Superorder (folding)- Exopterygota (incomplete metamorphosis) and Endopterygota(complete metamorphosis)
Giant Insects
Dragonfly that was 27 inches. Ephemeroptera was 17 inches. They were so large back than because of oxygen. There was 30% more O2 and flying vertebrates caused the large insects.
History
- Carboniferous=3 main feed strats= External, Internal, and full developed predators. Plants were largely ferns.
- Permian=Gymnosperms developed and insect diversity exploded. More food for insect, thin cortex and phloem
- Triassic=Dinosaurs and mammals orgin. Diversification of insects and major orders represented.
Amber Insects
Cretaceous to Tertiary plant secretion led to high quality preservation.
Mouth-Parts
Beak like mouth parts and expanded clypeus were evidence of feeding on phloem and other plant parts
Morphological Evolution of Insects and Mammals
- Humans have fast rate of evolution compared to insects due to recent radiation and major extinctions.
What was the first insect?
The first insect was terrestrial. Tracheal system evolution show that gills form only after tracheal system. Proof of terrestrial first.
Insects vs Animals
Insects have way more species than animals
What events cause more species in insects?
Evolution of wings- no limbs were lost and they did not come from gills. Epicoxa means wings develop from base of legs. Paranota means it came from thoracic terga. There is genetic evidence that wings develop from both, fusion hypothesis.
Early Wings Function (non-flight)
Protect legs, covers spiracles, thermoregulation, sexual display, concealment, escape
Evolution of flight
Only paragliding, not floating, running and jumping, and surface sailing across water. Earliest wings used for paragliding.
Folding wings
Neoptery, dragonfly and mayfly are NOT examples since they can’t fold wings.
Insects with wings and that can fly have way more species than insects without wings. WHY?
Increased mobility=more resources/habitats. Evade predators.
Allopatric speciation and Sympatric speciation and Parapatric speciation
Allopatric=Species that arise from being geographically isolated.
Sympatric= Species arise in same area by temporal shifts/behavior
Parapatric=Species arise from spacial separation but share border.
Complete Metamorphosis
Eggs to larva to pupa to adult
Evolution of Metamorphosis
- Permits adult to feed on new resources
- Permits adult to exploit new habitats
- take advantage of new situation
Characteristics of Insect Success
1) Small size=more niches available to small animals
* 5 species of insect only marine. 97% terrestrial, 3% aquatic. Insects specialize in niche.\
2) Enormous reproductive rate. Fecundity, longevity, generation, an time are all factors.
3) Tough exoskeleton
4) Flight
Biogeography
Study of the distribution of species and ecosystems in geographic space through geologic time. Insects show patterns of restriction in one area so entomologists are prominent biogeographers.
* just think insect distribution
Becoming more difficult due to Anthropophilic insects, humans disturb habitats, parasites, dissemination, deliberate movement.
Bottom line: Applied entomologists must take worldwide perspective
