Unit 1 Diversity of Living Things – pg. 145
22. Sponges are asymmetrical, meaning there is no regularity to their body form. Sea stars are
radially symmetrical, meaning that a single individual could be divided in half in numerous ways to produce a pair of symmetrical half-bodies. Human beings are bilaterally symmetrical, meaning that a single individual could be divided in half in only one way to produce a pair of symmetrical half-bodies
25. Bacteria perform important ecosystem services including decomposition and nutrient cycling. If all of the bacteria in an ecosystem were wiped out, plants may not get enough nutrients, which would decrease their growth and production, which would, in turn, affect herbivores and other consumers higher up in the food chain. Populations of these organisms would likely decrease as a result.
42. a. Sample answer: I agree with the change. It makes sense to have a common name that accurately describes an organism rather than promotes a misconception.
b. any reasonable answers regarding silverfish common names will be accepted
47. The first logical distinction would be prokaryotic and eukaryotic cell choices. Within the prokaryotes, the next (final distinction would be whether cell walls have peptidoglycan). Within the eukaryotes will be harder, but no cell walls would lead to animals and cell walls would leave the other three, then chitinous cell walls would distinguish fungi, leaving plants and protists which could be distinguished by treating plants as multicellular.
50. Some fungi are sources of antibiotics and some are sources of food (mushrooms, Roquefort cheese, soy sauce). Some fungi cause disease in humans or disease in plants that are important sources of food for humans.
54. a. Probably not since they look and sing differently
b. Do their off spring survive and are they fertile? (They do survive and they are fertile.)
c. You would need information about DNA sequences.
59. a. morphological species concept
b. genetic species concept
Unit 1 Self-Assessment Questions
(Student textbook pages 150–1)
20. A saprobe is an organism that feeds on dead organisms or organic wastes. Saprobial fungi are decomposers whose mycelia absorb nutrients from dead or decaying organic matter. They play an important role in the recycling of nutrients in ecosystems. Removing this group would disrupt the nutrient cycles resulting in fewer nutrients being made available to plants (autotrophs).
25. Chondrichthyes has a skeleton made of cartilage. Osteichthyes has a skeleton made of bone.