Insect1 Flashcards
How many named species of insects are there?
925,000
4 key characteristics that distinguish insects from other arthropods
Six legs, three body segments, wings, exoskeleton made from chitin
What are the three body segments of all insects?
Head, thorax, abdomen
5 reasons why there are so many insects
Design of exoskeleton with repetitive segments, wings power flight, association with plants, sociality, holometabolous metamorphosis
3 types of biodiversity of insects
Genetic, taxonomic, habitat
Biodiversity metric that is the total number of tax
Richness
4 assumptions made when dealing with richness
Taxon identity does not matter, number of individuals per taxon does not matter, all individuals within a species are equal, when comparing locations, similar numbers of individuals collected
Type of richness that is number of taxa within a local area (local richness)
Alpha
Type of richness that is variation in alpha richness among sites (species turnover)
Beta
Type of richness that is number of taxa across all sites in region (regional richness)
Gamma
What does Hurlbert’s PIE measure?
Probability that 2 randomly sampled individuals represent different species
When was the Paleozoic period?
414-247 mya
When was the Devonian epoch?
414-358 mya
3 characteristics of Devonian epoch
Arborescence evolved in plants, plants changed atmosphere, first “insect” fossils appear
When was the Carboniferous epoch?
359-290 mya
3 characteristics of Carboniferous epoch
Plant and insect diversity explosion, insects take flight, atmospheric oxygen very high
During the Carboniferous epoch, what did the high (35%) oxygen content of the atmosphere do to insects?
Allowed them to grow much larger
When was the Permian epoch?
290-248 mya
3 characteristics of Permian epoch
Largest insects ever, ends with mass extinction, decrease in oxygen concentration
When was the Mesozoic period?
247-65 mya
When was the Triassic epoch?
247-208 mya
3 characteristics of Triassic epoch
First “modern” families appear, ends with meteor impact, meteor did not affect insects
When was the Jurassic epoch?
207-146 mya
3 characteristics of Jurassic epoch
Dinosaurs dominate, insects don’t change very much, continent splits and fragments more
When was the Cretaceous epoch?
145-65 mya
4 characteristics of Cretaceous epoch
Fragmentation and drifting of continents, co-radiation of insects and angiosperms, most “modern” insect families appear, ends with extinction of dinosaurs
When was the Cenozoic period?
65 mya - present
Hypothesis for relatedness of taxa based on shared ancestry. Based on morphology, behavior, DNA
Phylogeny
Category of like individuals
Taxon
Phylogenetic group that includes all descendants of a common ancestor
Monophyletic
Phylogenetic group that includes some, but not all, descendants of a common ancestor
Paraphyletic
Phylogenetic group that includes some descendants, but not the ancestor
Polyphyletic
Term that describes “advanced” traits. Shared trait that is recently evolved and appears only in a group of related species.
Apomorphy
Term that describes “primitive” traits. Trait that arose in a distant ancestor and is shared by members outside the group.
Pleisiomorphy
3 examples of pleisiomorphies of mammals
Vertebrae, eyes, 4 limbs
2 examples of apomorphies of mammals
Fur, mammary gland
2 characteristics that constitutes a useful taxonomic group
Monophyletic, shared derived characters
2 challenges of monophyly in taxonomy
Convergent evolution, secondary loss of derived characters
Independent evolution of similar characters
Convergent evolution
E.g. loss of hind wings in flies/photosynthesis in parasitic plants
Secondary loss of derived characters