Understanding Evolution - The Arthropod Story
1. List the five main groups of arthropods.
insects, spiders, scorpions, crustaceans and centipedes.
2. Sheer Numbers …
a) How many insects exist for every human? __ 160 million ___
b) If all the ants on the earth formed a chain, how many times could the
earth be circled? _ 125,000 times
c) What are the most abundant animals in the ocean? ___ copepods _____
3. Habitat and Distribution
a) What arthropod lives more than a mile below the ocean? ___crabs___
b) Where does the largest centipede species live? _Amazon, S. AMerica_________
c) What arthropod lives at high altitudes? ______jumping spider_____________
d) What arthropod can withstand heats of over 140 º? _____melophorus ants____________
4. Ecological Niches
a) What type of arthropod is a farmer? _____leafcutter ants________
b) Where does the parasitic arthropod Cymothoa exigua live? ____fish's mouth______
c) What type of arthropod cleans fish scales of parasites? _____cleaner shrimp_______
5. Arthropods: A Success Story: Name one reason why arthropods are considered successful.
around for more than 500 million years , many shapes and sizes, overwhelming numbers, fill a variety of niches
6. Inherited Characteristics: List the five inherited characteristic of arthropods. bilateral symmetry, segmented bodies, exoskeleton, jointed legs, many pairs of limbs
7. a) Describe bilateral symmetry.
_________has a left and right side________
b) Check those that are bilaterally
symmetrical. _X_ millipede ____jellyfish __X__scorpion
8. a) Segments are grouped
into larger sets, such as the abdomen and the ____cephalothorax_____
b) Check those that are segmented. ___onychophoran __X__ mouse ___jellyfish
__X__moth
9. a) What substance is the
exoskeleton made from? _______chitin________________
b) Check those with an exoskeleton ____ mouse __X__moth _____ jellyfish
___X__millipede
10. a) Side Trip: Support Systems.
Name the three types of support systems found in the animal kingdom. __________endoskeleton, exoskeleton, hydrostatic skeleton_________________
b) Which one is possessed by humans? ______endoskeleton____________________
c) What kind of skeleton does an earthworm have? _____hydrostatic_____________
11. Jointed Legs a) What does the word "arthropod"
mean? _______joint foot_____________________
b) Check those that have jointed appendages.
__X__millipede _X_ moth ____ onychophoran _X_ mouse ____ jellyfish
12. a) Name five ways in which limbs can be specialized. defense, feeding, walking, swimming, sensory
b) Which have many pairs of limbs? ____ mouse _X moth _X__ millipede__X_scorpion
13. Based on these data, check all of the following animals that are arthropods.
scorpion X
mothX
14. A Closer Look at the Arthropod Branches
a) How many body parts do insects have? ___3___ How many pairs of legs
___6____
b) How many body parts do chelicerates
have? ___2_____ How many pairs of legs ____4_____
Do chelicerates have antenna? ___no______
c) Do crustaceans have antenna? ___yes_____ Give two examples of crustaceans. __ crabs, pillbugs, and barnacles _____
d) Give two examples of myriapods:
_________millipede, centipede____________________
e) Name the 3 lobes of the trilobite body: __________ cephalon, thorax, and pygidium _________________
15. Meet the Cambrian Critters: a) How long ago was the
Cambrian period?____ 570 to 530 million years ago ______
b) What is the "Cambrian Explosion" ________ burst of life forms occurred___________________
16. Sanctacaris
a) Nickname __________ Santa Claws ___
b) Is it part of the arthropod lineage? ________yes________
c) Sanctacaris added as a branch to what part of the tree ___chelicerate____________
17. Opabinia
a) How did it acquire food? ____tube-like probosscis________
b) Is it part of the arthropod lineage? __________no_______
c) Opabinia lacks what namesake trait of arthropods? __jointed legs________________
18. Pikaia
a) Is it part of the arthropod lineage? ___no_____________
b) Pikaia was probably what type of animal? _____chordate________
19. Hallucigenia
a) Is it part of the arthropod lineage? _____no__________________
b) Hallucigenia added as a branch to what part of the tree ______ onychophoran _______________
20. Naraoia
a) Is it part of the arthropod lineage? ______yes______________
b Naraoia added as a branch to what part of the tree ___trilobite_______________
21. Tools for Success - Crustaceans: Living Toolboxes.
For each tool, name the arthropod that has a similar appendage.
Crowbar __________coconut crap______________________________
Paddle _____________remipedes_____________________________
Broom ____________barnacle________________________________
Leaf blower ____________krill, use legs as fans___________________________
Clamp ______________caprella___________________________
Sledgehammer ______praying mantis________________________
22. Arthropod Adaptability: Describe two ways the legs of arthropods are adapted for different
purposes.
grasshoppers for jumping, bees carry pollen, lice for grasping
26. Sidetrip: Extreme adaptations: Eating with your feet. Sketch the head of an insect and label the mouthparts
show first maxilla, second maxilla and mandibles - See http://evolution.berkeley.edu/evolibrary/article/side_0_0/extreme_adaptations_01
27. a) What is an evolutionary constraint?_______ helps explain why something didn't or doesn't evolve _________________b) What are three constraints on arthropods? ______molting, respiration, exoskeleton__________________
28. Why does molting limit an arthropod's size? _____takes time to grow new skeleton__________________
29. How does strength limit the arthropod's size? _______muscles cannot support heavy skeleton_______________________
30. a) How do insects get oxygen? __________ get oxygen through tubes ____________________________
b) How does this limit their size? ________large insects can't get enough oxygen_______________________