Rank the three most diverse phyla of protostome animals.

a. Arthropoda > Mollusca > Nematoda

b. Mollusca > Arthropoda > Nematoda

c. Arthropoda > Nematoda > Mollusca

One trait that is shared by humans and protostomes is __________.

Which protostome phyla successfully made the transition from water to land? Select True or False for each phylum.

T/F Mollusca

T/F Arthropoda

T/F Annelida

T/F Nematoda

Propose an explanation for why annelids and arthropods were thought to be closely related, before phylogenetic analyses in the late 1990s.

Use your understanding of insect evolution to predict two adaptations for terrestrial living that occurred in spiders.

Pose a hypothesis to explain why the evolution of the wing was such an important event in the evolution of insects.

Which of these choices is an example of homology (similarity due to common ancestry)?

a. Suspension feeding in sponges and clams

b. Ectoparasite lifestyle in aphids and ticks

c. Cnidocytes (stinging cells) in jellyfish and sea anemones

d. Radial symmetry in cnidarians and echinoderms

Evaluate this statement: Evolution is said to occur when new traits accumulate over time, increasing complexity.

The pygmy zebra octopus is a potential new model organism for understanding brain function in humans despite the independent evolution of high intelligence in both groups. Describe (or draw a phylogenetic tree to show) the relationships among humans (H. sapiens), the pygmy zebra octopus (O. chierchiae) and two other protostome model organisms in medicine: the fruitfly (D. melanogaster) and roundworm (C. elegans).

A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. Which of the following nested groups best describes the taxonomic context for the San Lorenzo project?

a. Animalia > Bilateria > Arthropoda > Ecdysozoa

b. Protostomia > Lophotrochozoa > Ecdysozoa > Arthropoda

c. Arthropoda > Protostomia > Ecdysozoa > Bilateria

d. Bilateria > Protostomia > Ecdysozoa > Arthropoda

A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. Rather than measuring the entire 6000-hectare (ha) forest, the researchers sampled arthropod diversity by intensively collecting as many arthropods as they could in 12 plots that measured 20 m × 20 m square. If 1 ha=10,000 m², how many hectares of forest did they sample in all?

a. 20 m×20 m×12=4800 ha

b. 4800 m²×10,000 m²/1 ha=48,000,000 ha

c. 20 m×20 m=400 ha

d. 4800 m² x ha/10,000 m² = 0.48 ha

A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. The graph below shows some of the data for the major arthropod groups collected. Notice that the scale on the y-axis is logarithmic to make both small and large numbers legible on the same graph. For example, there are about 400 species of spiders but only 40 species of bees.

About how many arthropods were found in total?

About what percentage of these were beetles?

A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. Use the data in the graph to analyze the following statements.

Select True or False for each statement, then correct any false statements to make them true.

T/F All taxa shown in the graph are insects.

T/F All taxa shown in the graph have segmented bodies and limbs.

T/F All taxa shown in the graph are terrestrial.

T/F If the researchers had sampled for mollusks, they probably would have found almost as many species as they did for arthropods.

A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. By comparing the number of arthropod species that were common among the 12 plots sampled, the researchers estimated that the total number of arthropods in the whole San Lorenzo forest is 25,000 species.

To come up with this estimate, what's one assumption the researchers had to make about the forest?

A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. The researchers observed a strong correlation between the number of arthropod species and the number of plant species in the San Lorenzo forest.

Pose an evolutionary hypothesis to explain this correlation.