Understanding Evolution - The Arthropod Story

1. List the five main groups of arthropods.


2. Sheer Numbers …
a) How many insects exist for every human? ________
b) If all the ants on the earth formed a chain, how many times could the earth be circled? ____
c) What are the most abundant animals in the ocean? _______________

3. Habitat and Distribution
a) What arthropod lives more than a mile below the ocean? ___________
b) b) Where does the largest centipede species live? _________________
c) What arthropod lives at high altitudes? _____________________
d) What arthropod can withstand heats of over 140 º? ________________

4. Ecological Niches
a) What type of arthropod is a farmer? ______________________________
b) Where does the parasitic arthropod Cymothoa exigua live? _____________
c) What type of arthropod cleans fish scales of parasites? ________________

5. Arthropods: A Success Story: Name one reason why arthropods are considered successful.


6. Inherited Characteristics: List the five inherited characteristic of arthropods.


7. a) Describe bilateral symmetry. ________________________________
b) Check those that are bilaterally symmetrical. ___ millipede ____jellyfish _____scorpion


8. a) Segments are grouped into larger sets, such as the abdomen and the ______________
b) Check those that are segmented. ___onychophoran ____ mouse ___jellyfish ____moth


9. a) What substance is the exoskeleton made from? _________________________
b) Check those with an exoskeleton ____ mouse _____moth _____ jellyfish _____millipede

10. a) Side Trip: Support Systems. Name the three types of support systems found in the animal kingdom. _________________________________________________________
b) Which one is possessed by humans? __________________________________
c) What kind of skeleton does an earthworm have? __________________________

11. Jointed Legs
a) What does the word "arthropod" mean? ____________________________________
b) Check those that have jointed appendages.
____millipede ___ moth ____ onychophoran ___ mouse ____ jellyfish

12. a) Name five ways in which limbs can be specialized.

b) Which have many pairs of limbs? ____ mouse ___ moth ____ millipede_____scorpion

13. Based on these data, check all of the following animals that are arthropods.

scorpion checkbox moth checkbox onychophorancheckbox mouse checkbox millipede checkbox jelly checkbox

14. A Closer Look at the Arthropod Branches
a) How many body parts do insects have? _______ How many pairs of legs _______
b) How many body parts do chelicerates have? ____ How many pairs of legs _____Do chelicerates have antenna? ____
c) Do crustaceans have antenna? _________ Give two examples of crustaceans. _________________
d) Give two examples of myriapods: ___________________________________________
e) Name the 3 lobes of the trilobite body: ________________________________________

15. Meet the Cambrian Critters a) How long ago was the Cambrian period?____________________
b) What is the "Cambrian Explosion" _____________________________________________

16. Sanctacaris
a) Nickname __________________________
b) Is it part of the arthropod lineage? ________________________
c) Sanctacaris added as a branch to what part of the tree ___________________________

17. Opabinia
a) How did it acquire food? _________________________
b) Is it part of the arthropod lineage? ________________________
c) Opabinia lacks what namesake trait of arthropods? _____________________________


18. Pikaia
a) Is it part of the arthropod lineage? ________________________
b) Pikaia was probably what type of animal? __________________________

19. Hallucigenia
a) Is it part of the arthropod lineage? ________________________
b) Hallucigenia added as a branch to what part of the tree ___________________________

20. Naraoia
a) Is it part of the arthropod lineage? ________________________
b Naraoia added as a branch to what part of the tree ___________________________

21.Tools for Success - Crustaceans: Living Toolboxes. For each tool, name the arthropod that has a similar appendage.
Crowbar _____________________________________Paddle _____________________________________
Broom _____________________________________Leaf blower _____________________________________
Clamp _____________________________________Sledgehammer _____________________________________

22. Arthropod Adaptability - Describe two ways the legs of arthropods are adapted for different purposes.


26. Sidetrip: Extreme adaptations: Eating with your feet. Sketch the head of an insect and label the mouthparts


27. a) What is an evolutionary constraint?_____________________________________________
b) What are three constraints on arthropods? ____________________________________________

28. Why does molting limit an arthropod's size? ____________________________________________

29. How does strength limit the arthropod's size? ____________________________________________

30. a) How do insects get oxygen? ______________________________________________________
b) How does this limit their size? _____________________________________________________