Transcript No Slide Title

Arthropod phylogeny
&
Insect Evolution
Objectives:
Identify characteristics of the Arthropoda
Discuss Arthropod Phylogeny
Characteristics of major taxa
Discuss Insect Evolution
Arthropoda
Arthro- Refers to Joints
Poda- Refers to feet
Arthropoda
Characteristics
• Paired, jointed appendages
• Segmented body plan
• Land forms have tracheae
or book lungs,
• Aquatic forms have gills
Arthropoda
Characteristics
• Compound eyes
• Open circulatory system
• Digestive system is a tube
• Nervous system with brain,
paired ventral nerve cords
Arthropoda
• Exoskeleton is molted
Arthropoda
Arthropoda
• Evolved from Annelida
Ecdysozoans
Arthropoda Phylogeny
• Many hypotheses exist
• Molecular data suggest:
Arthropoda Classification
Chelicerata
Mandibulata
Hexapoda = antennae
Arthropoda Classification
• Chelicerae = feeding appendages
= fangs in spiders
Arthropoda Classification
1. Chelicerata
Classes:
Merostomata horseshoe crabs
Arachnida - spiders,
scorpions, ticks, mites
Arthropoda Classification
Chelicerata
• Mainly terrestrial
• Body Divisions - Cephalothorax, abdomen
• No antennae
• No chewing mandibles
Arthropoda Classification
Chelicerata
• First and second pair of appendages chelicerae, pedipalps used for manipulation
of food, locomotion,
defense, copulation
• Next four pair of
appendages - walking
Arthropoda Classification
Crustacea
• Aquatic
• Body divisions - cephalothorax and abdomen
• Gills
• 2 pairs antennae - touch and taste
• Biramous appendages - two jointed branches
arising from their base
- biramous appendages
Arthropoda Classification
Crustacea
• Mandibles and maxillae used for feeding
• Chelipeds on lobsters and crayfish - pinching
claws
• Larval stage
• Green glands
Arthropoda Classification
Hexapoda
Class:
Insecta - insects
Arthropoda Classification
Insecta characteristics
Terrestrial and some aquatic
Body plan - Head, thorax, abdomen
Uniramous
1 pair antennae
3 pairs legs on thorax
Malpighian tubules
Insect Evolution
• Four stages of insect evolution:
1. Development of insect body form
2. Development of wings
3. Development of wing flexion
4. Development of complete metamorphosis
Orders:
Ephemeroptera = ?
Odonata = ?
Plecoptera
Megaloptera
Coleoptera
Lepidoptera
Diptera