Q: Which equation describes the open circulatory system in arthropods, and what is the main fluid involved?

$$Q = SV \times HR$$; hemolymph is pumped by the heart into the hemocoel.

Question 1

Which phylum is considered basal among animals and lacks true tissues, as shown in the evolutionary diagrams provided?

Accepted Answer

Porifera

Question 2

In the evolutionary diagrams, which clade is highlighted as the oldest phylum of Eumetazoans, possessing true tissues?

Accepted Answer

Cnidaria

Question 3

Referencing the image of millipede and centipede, which statement best distinguishes these two groups?

Accepted Answer

Millipedes have two pairs of legs per segment, while centipedes have one pair per segment.

Question 4

Based on the tapeworm anatomy image, which structure is responsible for attaching the tapeworm to its host's intestine?

Accepted Answer

Hooks and sucker on the scolex

Question 5

The pill bug shown in the image is an example of which group of crustaceans, and what is a key adaptation for terrestrial life?

Accepted Answer

Isopod; ability to exchange gases through the cuticle

Question 6

Oysters, as shown in the image, belong to which molluscan class, and what is their primary feeding mechanism?

Accepted Answer

Bivalvia; suspension feeding using gills

Question 7

The lophophore, as seen in the ectoproct image, is primarily used for which function?

Accepted Answer

Feeding by filtering particles from water

Question 8

Which phylum includes animals with a water vascular system used for locomotion and feeding, and what is the main symmetry of their adult form?

Accepted Answer

Echinodermata; radial symmetry

Question 9

Which group of animals is characterized by ecdysis, the process of molting a cuticle, and includes both nematodes and arthropods?

Accepted Answer

Ecdysozoa

Question 10

Which of the following statements about flatworms is correct regarding their body plan and gas exchange?

Accepted Answer

Flatworms are acoelomates and rely on diffusion across their body surface.

Question 11

Which equation best describes the relationship between surface area and volume as an organism grows, and why is this important for flatworms?

Accepted Answer

As volume increases, surface area increases at a slower rate: $$	ext{Surface Area} \propto 	ext{Volume}^{2/3}$$; this allows flatworms to maximize exchange by being flat.

Question 12

Which structure in annelids is used for locomotion and gas exchange, and what is it composed of?

Accepted Answer

Parapodia; bristles made of chitin

Question 13

Which phylum includes animals with a closed circulatory system, a complex brain, and tentacles modified from the foot?

Accepted Answer

Cephalopoda (Mollusca)

Question 14

Which group of insects undergoes complete metamorphosis, and what is a key feature of their larval stage?

Accepted Answer

Coleoptera; larval stage specialized for eating and growing

Question 15

Which equation represents the hydrostatic skeleton function in cnidarians, and what is its biological significance?

Accepted Answer

$$P = F/A$$; contractile cells exert force against the gastrovascular cavity to produce movement.

Question 16

Which phylum is most threatened by habitat loss, pollution, and overharvesting, especially among freshwater and terrestrial species?

Accepted Answer

Mollusca

Question 17

Which group of animals is characterized by a segmented body, jointed appendages, and a chitinous exoskeleton?

Accepted Answer

Arthropoda

Question 18

Which equation describes the open circulatory system in arthropods, and what is the main fluid involved?

Accepted Answer

$$Q = SV 	imes HR$$; hemolymph is pumped by the heart into the hemocoel.

Question 19

Which phylum includes animals with a coelom, an endoskeleton of calcareous plates, and tube feet for movement?

Accepted Answer

Echinodermata

Chapter 33: An Introduction to Invertebrates – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards