Intro To Arthropods

1
Intro To Arthropods

• HW Complete page 1 in RB 2 (Resource book 2
  the pink one)

2
Overview

• Arthropods have been around for 500 million
  years.
• There are about a million known species of
  arthropods.
• This are more species in this one phylum than you
  would get by grouping all members of all other
  phyla together.
• There are 160 million insects for each person on
  this Earth.
• There are so many copepods tiny crustaceans
  that together they outweigh all the whales on
  Earth.

3
Habitat

• Given that there are a million of different
  species, they are found in almost all habitats on
  Earth.
• Many crustaceans live in the sea at depths
  exceeding 4,000 metres. (Thats 2.5 miles deep)
• Insect collembolans and jumping spiders have been
  found on Mount Everest at heights exceeding 6,700
  metres. (Thats 4 MILES high.)
• Collembolans and the orbatid mites live in
  Antarctica. 
• Brine shrimp are found in some saltwater lakes.
• Beetles, mites, and various crustaceans can live
  in hot springs. 
• Tiny crustaceans inhabit underground waters.
• Deserts support a large arthropod population,
  especially insects and arachnids.

4
Niches

• All are free-living, and the aspects of their
  niche that affect humans include
• Many species of insects and mites attack food
  crops and timber. 
• Two-thirds of all flowering plants are pollinated
  by insects.
• Soil and leaf-mold arthropods, which include
  insects, mites, myriapods, and some crustaceans
  (pill bugs),
• play an important role in the formation of
  humus from decomposed leaf litter and wood.
• To protect themselves many arthropods (insects)
  will sting their attacker.

5
Medical Importance

• Medically, arthropods are significant as carriers
  of diseases, including
• Malaria
• Yellow fever
• Dengue fever
• African sleeping sickness (via tsetse flies)
• typhus fever (via lice)
• bubonic plague (via fleas)
• Rocky Mountain spotted fever (via ticks)
• Lyme disease (via ticks)

6
Arthropod Characteristics

• What makes an organism an arthropod?
• Exoskeleton
• Segmented Body with paired appendages
• Bilateral symmetry
• One way digestive system (mouth and anus)
• Open circulatory system
• Separate sexes

7
Arthropod Subphyla Classes

• There are many different classes of Arthropods,
  including
• Class Merostomata (horseshoe crabs,
  eurypteridssea scorpions)
• Class Arachnida (spiders, ticks, mites)
• Class Crustacea
• Class Chilopoda (centipedes)
• Class Diplopoda (millipedes)
• Class Insecta