Class Arachnida (Spiders & their Relatives)

 Characteristics of All Arachnids (Spiders, Scorpions, Mites, and Ticks)





















Adaptations to live on land

Air -> _____________________ (openings) -> ____________________ -> oxygen from air is moistened -> dissolved into blood stream



Common functions of Silk include:







Courtship Rituals of Spiders














* Punch holes in skin; cause severe itching
* Carry viruses that damage food crops
* Cause feather loss in birds; mange in dogs
* Cause decreased wool production in sheep




Horseshoe Crabs 




Class Insecta (Insects, Millipedes, Centipedes)

 Insects (Grasshoppers, beetles, termites, fleas, ants)


_________________________ - The study of insects












Adaptations to live on land:




Development in Insects

 Direct Development (Spiders, scorpions, ticks) – A miniature copy of the adult form hatches from the egg.

Incomplete Metamorphosis (Grasshoppers, dragonflies, mayflies, cockroaches) –





Nymph – A smaller version of the adult, similar structure without wings or a mature reproductive system


Complete Metamorphosis (Flies, beetles, ants, wasps, bees, butterflies, moths) –









      Larva – Immature form of an insect  (ex: caterpillar)


      Pupa Stage  - Insect forms a cocoon; tissues & organs are replaced with new ones.


Insects can be Harmful:

* Eat plants
* Transmit diseases to plants and animals (sleeping sickness, malaria)
* Become resistant to pesticides

Insects can be Beneficial:

* Pollination of food crops
* Production of silk (caterpillars of silk moths), honey & beeswax (bees)
* Food source in some parts of the world (grasshopper tacos – yummy!)
* Stabilize ecosystems


 Millipedes “Thousand feet”




Cenitpede “Hundred feet”





Class Crustacea  (Crayfish, lobsters, pillbugs, beach hoppers, barnacles, copepods)

Characteristics of Crusteans  (successful Aquatic Arthropods)


Cannot live on Land because:


Decapods “10 feet”    (Lobsters, shrimp, crabs, crayfish)


Isopods  “Equal feet”    (Pill bugs & relatives)


Amphipods  “Two different kinds of feet”    (Beach hoppers)





Daphnia  (Water Flea)




General Biology College Prep Biology Feedback Page
Class Rules & Procedures Science Links & Resources Online Tools for Data Analysis
Search Engines Parent's Page Teacher Online Toolbox


Return to Home Page