The Arthropods: Blueprint for Success

1. The Arthropods: Blueprint for Success

3. Taxonomy we will cover in this Phylum: • Subphylum Crustacea • Class Malacostraca • Exp. Lobster • Class Cirripedia • Exp. Barnacles • Subphylum Chelicerata • Class Merostomata • Exp. Horseshoe crab • Class Arachnida • Exp. Spiders

4. General Facts • Over a million species • Between 70-85% of all named species on Earth are Arthropods. • The majority being insects! • Live on land, oceans, & freshwater. • Range in size from 12 ft. armspan (King Crab) to microscopic insects & crustaceans & range in taste 

5. King Crab!

6. Horseshoe Crab Find mates in water Go to beach & mate (leave sea briefly) and lay eggs Eggs develop on land

7. Spotted Cleaner Shrimp

8. Pumpkin Spider

9. Giant Weta

10. Peruvian Giant Centipede

11. Millipede

12. 6 Key Features to Arthropod Success: • Metamerism • Exoskeleton • Jointed Appendages • Efficient Respiratory System • Sensory Structures • Complex Behaviors

13. Arthropod Success-A group of animals with a proper toolkit to dominate. Metamerism– segments are grouped into body regions; allows for specialization. • Tagmata - specialized for feeding and sensory perception, locomotion, and visceral functions. (segments fused together) Exoskeleton– skeleton outside body.Protection (body armor), support, H2O retention, muscle attachment • Ecdysis (molting) – emerges with entire new covering (soft at first..then hardens over 2 days) Jointed appendages – adapted for a variety of functions - imagine yourself w/out joints.

14. Success continued… Efficient Respiratory System– tracheal system of tubes throughout the body with tiny openings (spiracles) that open into the trachea – tubes • Allows for direct access of oxygen to muscles More Developed Sensory Structures– allow organisms to be more aware • Compound eyes, antennae, etc. Complex Behaviors– no big development in nervous system; but migrates every year, social behavior, can learn • Allows better survival and more generations

15. Each leg has tremendous flexibility • Saltatorial, cursorial, etc. • Muscles can attach to exoskeleton • Legs and body segments = potential to adapt & evolve

16. Metamorphosis Physical change over time; one body form to another • Complete (holometabolous) (indirect) • Egg  Larva  Pupa  Adult • Larva & Pupa do not look like adult • Incomplete (hemimetabolous) (direct) • Egg  Nymph (instars)  Adult • Instars look like mini adults

17. Incomplete (hemimetabolism) (Direct)

18. Complete (holometabolism) (indirect)

19. EXTINCTARTHTROPOD • Trilobites! • Dominant form of life in the oceans during the Cambrian period. • Body oval, flattened & dividedinto 3 sections, had eyes, could walk & swim, roll in a ball for protection.

20. Subphylum Crustacea • Crayfish, shrimp, lobster, crabs, copepods, isopods. • 2 pairs of antennae, bi-ramous appendages.

21. Class MalacostracaOrder Decapoda • Shrimp, crayfish, lobster, crabs. • Have a cephalothorax and abdomen. • They eat anything! • Gills are in the carapace between body wall. • Sensory structures: antennae, compound eyes, simple eyes, statocysts, chemoreceptors, proprioceptors, tactile setae.

22. Exoskeleton (molted) • Draw & label a crayfish – antennae, antennules, cephalothorax, abdomen, uropod, telson, swimmerets, walking legs, cheliped, rostrum, carapace, eye

23. Order Decapoda • Isopods (pill bugs) are common under rocks and in leaf litter. • Copepods are the most abundant.

24. Subphylum CrustaceaClass Cirripedia • Barnacles • Unique because they are sessile (attached to a substrate).

25. Barnacle Life Cycle Direct or Indirect?

26. Subphylum Chelicerata Includes the horseshoe crabs, sea spiders, spiders, mites, & ticks.

27. Chelicerata Characteristics 2 tagmata- cephalothorax & abdomen Mandible – jaw for chewing Chelicerea - (used for feeding) • Located on cephalothorax Pedipalps - (sensory or feeding) • Located on cephalothorax.

28. Subphylum ChelicerataClass Merostomata • Includes horseshoe crabsand the giant water scorpion (extinct). • Horseshoe crabs have remained virtually unchanged for 200 million years. • They have a long tail-like extension (telson) that helps it flip over. • Dioecious– lay eggs in intertidal areas.

29. Subphylum ChelicerataClass Arachnida • Spiders, ticks, mites, scorpions. • Most are carnivorous – they use chelicerae to hold food while injecting it with digestive enzymes & suck out the tissue.

30. Subphylum ChelicerataClass Arachnida continued… • Either have book lungs(folds in the body wall that allow gas exchange) or • tracheae(tubule system- opens to the outside through spiracles & allow oxygendirectly into body tissue

31. Arachnid Development • Direct life cycle– young hatch as mini adults. (Hemimetabolism)

32. Arachnids Impact Humans • Humans have been impacted the most by Acarines (ticks & mites). • Can transmit disease and cause irritation.

33. Subphylum MyriapodaClass Chilopoda vs. Class Diplopoda • centipedes vs. millipedes • Fast moving vs. slow moving

34. Subphylum HexapodaClass Insecta Entomology – study of insects 3 tagmata – head, thorax, & abdomen • Head region – specialized for feeding and sensory input • Thorax – specialized for movement • Abdomen – specialized for respiration, digestion, reproduction, etc.

35. Class Insecta continued.. • Many types of mouths – chewing, piercing, sucking, etc. • Silk glands – movement, create nests/webs • Pheromones – chemical substance released outside of the body and influences other organisms • Exp. sex pheromones (beetles, attack pheromones (honeybees)

36. Draw and label an insect: • Include: 3 segments, compound eye, ocelli (simple eyes), mandible, labrum, antennae, thorax (pro, meso, meta) abdomen, tympanum, ovipositor (female only), leg (5 parts), jumping leg, protective wing, flight wing, spiracles