ENT201 - Exam 1 - The Family Tree

A fraction of all living species that are arthropods

2/3 of all identified species

Fraction of all identified species that are insects

1/2 of all identified species

Number of Insects per Human on Earth

200,000,000

Phylum Arthropoda

• Segmented bodies

• Jointed appendages

• Chitinous exoskeleton

• Bilateral symmetry

Bilateral symmetry

Only one plane of symmetry divides the body into two identical halves

Class #1 crustacea

• A class of primarily aquatic arthropods

• 4 antennae and 10 limbs

• Lobsters, crabs, shrimps

Physical reason crustaceans can grow to large physical sizes

Because they live in water, buoyancy makes them weightless, relieving gravitational constraints

Class #2 Chilopoda

• Centipedes

• 100 legs

• Multi-segmented predatory arthropods

• 1 pair (2 legs) per segment

• Fangs and venom

Dietary habits and ecological role of centipedes

All are venomous predators that hunt arthropods, lizards, small rodents and birds

Class #3 Diplopoda

• Milipedes

• 1000 legs

• herbivorous/detrivorous

• Arthropods

• Rounded bodies

• 2 pairs (4 legs) per segment

Defensive mechanisms used by Class Diplopoda (Milipedes)

Rolling into a tight ball, utilizing barbed hairs, producing chemical defenses such as cyanide

Primary ecological function of milipedes in ecosystems

• Detritivores

• Feed on decaying plant material and fungi

Class #4 Arachnida

• Spiders, scorpions, ticks, mites

• 8 legs

• 2 body regions

• no antennae

• presence of pedipalps

Class #5 Insecta

• 6 legs

• 3 body regions

• 2 antennae

• external mouthparts

• 0,2, or 4 wings

Body regions in Class Insecta

3 body regions:

• head, thorax, abdomen

Linnaeus

• Established a modern system of binomial nomenclature in Systema Naturae

Mnemonic for taxonomic rank hierarchy

King Philip Cried ‘Oh For Goodness Sake’

KINGDOM

PHYLUM

CLASS

ORDER

FAMILY

GENUS

SPECIES

Benefit of binomial nomenclature over common names

Provides precise, globally standardized identification regardless of local language or common names

Language traditionally used for scientific naming of new species

Latin

Two components that make up a binomial scientific name

1. The genus (capitalized)

2. The specific species (lowercase)

all italicized