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clearest example, and perhaps electric shocks. For practical purposes why not assume that that is so? Most operations on insects are actually facilitated if the insect is narcotizedâ (pp. 8â9). Bekoff (2002) writes: âWhile researchers are not sure which animals feel pain there is much evidence that animals who many people thought could not feel pain in fact, do. Fish, for example, have neurons similar to those that are associated with the perception of pain in other animals. Fish show responses to painful stimuli that resemble those of other animals, including humans. Even some invertebrates possess nerve cells that are associated with the feeling of pain in vertebrates. Whether some insects actually feel pain is not known, but because they might some people believe that they should be given the benefit of the doubtâ (pp. 143â44).

CHAPTER 6

P. 69: PLANTS

Attenborough (1995) describes a Venus flytrap in action: âAn insect, attracted by the nectar or the red coloration can crawl around on the surface of a lobe with impunity, provided it doesnât touch one of these bristles, for they are triggers. Even touching one is not necessarily lethal, for nothing will happen immediately. But if it touches the same one or another on the leaf within twenty seconds, thenâwith a swiftness that may alarm a watching botanist, accustomed as he is to more sedate reactions from his subjectsâthe two lobes snap together. The reaction takes no more than a third of a second. The stimulus that triggers it is an electric one, like that of the sensitive mimosa, but exactly what mechanism drives the closure is, even now, not fully understoodâ (pp. 84â85).

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P. 70: DEFINITION OF âANIMALâ

The Concise Oxford Dictionary defines an animal as âa living organism which is typically distinguished from a plant by feeding on organic matter, having specialized sense organs and nervous system, and being able to move about and respond to stimuli.â

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P. 71: SPONGES

Leys and Mackie (1997) write: âSponges arose very early in metazoan evolution. They do not have a nervous system, but some respond to stimulation by producing local contractions and one group, the âglass sponges,â shows coordinated arrests of movements of the flagella, which produce the feeding current. We show here that these arrests are coordinated by propagated electrical impulses. This is, to our knowledge, the first report of electrical signaling in any spongeâ (p. 29). See also Leys et al. (1999).

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P. 71: HYDRALIKE CREATURES AT THE ORIGIN OF HEAD DEVELOPMENT

Bhattacharjee (2003) writes: âIn their quest for the origin of the head, scientists have identified genes in corals, sea anemones and hydra that are similar to genes responsible for head development in higher animals like flies and mice. Studying such homologous genes across species, which have closely matching protein sequences, is a standard technique used by researchers to trace the ancestry of physical and behavioral traits. In experiments on hydra, Dr. Brigitte Galliot and her colleagues at the University of Geneva studied genes that were similar to head-development genes in the fruit fly. They chopped off the top of a hydra and monitored the expression of specific proteins regulated by these genes as the organism regenerated its lost part. From the pattern of proteins expressed during the regeneration process, the researchers concluded that the genes were involved in forming the hydraâs upper region, including the organization of nerve cellsâ¦These findings suggest that the head in higher animals may have evolved from a mouth-like structure similar to the cnidarianâs upper body, consisting of a nerve net around an oral opening. A larger conclusion, according to Dr. Galliot, is that the headâs origin may have been driven by the need for active feedingâ (p. 2).

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P. 72: SNAILS

Muséum National dâHistoire Naturelle (1999): âA snail possesses several thousand neurons. But impulses circulate at a very slow rhythm in its nervous system. Several seconds may elapse between the exterior stimulus and the muscular response. As far as