To estimate the relative abundance of the major phyla, calculate how many named species of arthropods, mollusks, and nematode worms exist per named species of chordate (the phylum containing vertebrates, including humans; see Table 30.1). Do you think these calculations are likely to be underestimates or overestimates? Why?

Verified step by step guidance

1. Identify the number of described species for each phylum: Arthropoda (1,200,000), Mollusca (85,000), Nematoda (25,000), and Chordata (65,000).
2. Calculate the ratio of species in each phylum to the number of species in Chordata: Arthropoda/Chordata = 1,200,000/65,000, Mollusca/Chordata = 85,000/65,000, Nematoda/Chordata = 25,000/65,000.
3. Perform the division for each ratio: Arthropoda/Chordata = 18.46, Mollusca/Chordata = 1.31, Nematoda/Chordata = 0.38.
4. Interpret the results: There are approximately 18.46 arthropod species, 1.31 mollusk species, and 0.38 nematode species for every chordate species.
5. Discuss potential underestimation or overestimation: These calculations might be underestimates because many species, especially in less-studied phyla, may not yet be described.