ENT201 - Exam 1 - Older Than Dinosaurs or Insect History

Trilobites - key characteristics

• Arthropods

• Extinct

• Marine

• Lived in ancient oceans 550-250 million years ago

Horseshoe crab - evolutionary relation

Closely related to spiders

Horseshoe crab - medical significance

Their bright blue blood is harvested to test medical supplies for bacterial contamination

Arthropods - key characteristics

• Jointed appendages

• segmented bodies

• bilateral symmetry

Amber

• Fossilized tree resin

• Preserves trapped organisms in great detail

• Only gemstone that burns

Typical age of amber insect fossils

30-60 million years old

Appearance of the first insects

Tiny, wingless, soft-bodied organisms that moved from water to land around 420 million years ago

Insect flight emergence timeline

Around 300 million years ago, with the ancestors of dragonflies and mayflies

Earliest recorded human-insect interaction artwork

Cave drawings around 6,000 BC showing humans collecting honey from bees

Aristotle’s contribution to zoology

Known as the father of Zoology; wrote Historia Animalium

Theophrastus

Ancient Greek scholar who was the first to catalog insect crop pests

Pliny the Elder

Roman author who dedicated Book 11 of his work Historia Naturalis to insects

John Sperling’s 1661 estimate of species

• Estimated at around 40 beetles

• 50 caterpillars

• 70 flies

• over 100 butterflies

• All in Zoolgia Physica

John Ray’s 1700 global insect estimate

Estimated that there were approximately 10,000 total insect species in the world in Historia Insectorum

Linnaeus

Established the formal binomial system of nomenclature in Systema Naturae (10th ed., 1758)

Biological definition of a species

One or more populations of interbreeding individuals that produce fertile, reproductively isolated offspring

Number of identified insect species

1,000,00 named and identified species

silk cultivation history

Cultivated for 6,000 years in Asia

True classification of ladybugs

• Beetles (order Coleoptera), not true bugs

Griffinflies

Extinct giant flying insects

• closely related to modern dragonflies

First animal group to achieve flight

Insects (one of only four animal groups to ever achieve true flight)

Evolutionary advantage of insect flight

Allows small organisms to exploit scattered resources and traverse large distances efficiently

Timeline for present-day insect species presence

Many modern insect species were present by the mid-Tertiary period (~25-30 million years ago)

Horseshoe crab structural trait shared with trilobites

A hard, protective chitinous exoskeleton

Timeline for modern insect relatives

Most modern insect relatives were present before the Jurassic period (~180 million years ago)