Question

1 complete summary table a - 1 in the appendix, filling in the characteristics of both malacostracans (crayfish) and insects (grasshopper) in the appropriate rows.
2 what phylum is considered to be the arthropods closest relative? what major characteristic do arthropods share with this sister - group?
3 list at least two advantages of an exoskeleton.
1.
2.
4 what disadvantages associated with having exoskeletons did arthropods have to overcome to allow natural selection to favor this trait? how did they circumvent these problems?
5 which of the following respiratory structures is not found in arthropods?
a. gills
b. trachea
c. lungs
d. book gills
e. spiracles
6 match each organism to its correct class.
____ grasshopper a. class merostomata
____ centipede b. class arachnida
____ horseshoe crab c. class chilopoda
____ millipede d. class diplopoda
____ scorpion e. class malacostraca
____ crayfish f. class insecta
____ tick
____ crab
chapter 14 arthropods 291

Explanation:

1. This requires knowledge from the biology sub - field to fill in the table with characteristics of malacostracans and insects.
2. The closest relative phylum of arthropods and shared characteristics are biological concepts.
3. Advantages of exoskeletons are biological traits.
4. Disadvantages and how arthropods overcame them are biological adaptations.
5. Respiratory structures in arthropods are biological features.
6. Matching organisms to their classes is a taxonomic task in biology.

Answer:

1. (Requires referring to Appendix Table A - 1 and knowledge of malacostracan and insect characteristics)
2. The closest relative phylum of arthropods is Onychophora. They share the characteristic of having segmented bodies.
3. 1. Protection against predators and physical damage. 2. Prevention of water loss.
4. Disadvantage: Restricts growth. Solution: Periodic molting (ecdysis) to shed the old exoskeleton and grow a new one.
5. c. lungs (while some terrestrial arthropods have tracheae, spiracles, and some aquatic ones have gills or book gills, lungs are not typical respiratory structures in arthropods)
6. grasshopper - f. Class Insecta

centipede - c. Class Chilopoda
horseshoe crab - a. Class Merostomata
millipede - d. Class Diplopoda
scorpion - b. Class Arachnida
crayfish - e. Class Malacostraca
tick - b. Class Arachnida
crab - e. Class Malacostraca