Through glassy, half-frozen eyes I looked up and saw the silhouettes of hundreds of amused gawkers standing on the pier. Through water-clogged ears I heard their taunts and laughter.

I felt the muddy bog beneath me and stumbled to shore, my numb fingers still struggling to release the metal catch of my cursed backpack.

True pulled the waterlogged sack off me. "Are ye okay?"

I nodded, then collapsed to my knees, my body shivering from the cold. "Bastards. I'll kill 'em."

"Now ye sound like yer faither. Let them go. Before all's said an' done, we'll get oor revenge."

I nodded, anger once more fueling my resolve.

Evolution usually proceeds by "speciation"—the splitting of one lineage from a parental stock—not by the slow and steady transformation of these large parental stocks. In the allopatric theory, popularized by Ernst Mayr, new species arise in very small populations that become isolated from their parental group at the periphery of the ancestral range. Speciation in these small isolates is very rapid by evolutionary standards—hundreds or thousands of years (a geological microsecond). Major evolutionary change may occur in these small isolated populations. Favorable genetic variation can quickly spread through them. Moreover, natural selection tends to be intense in geographically marginal areas where the species barely maintains a foothold. Small changes occur to meet the requirements of slowly altering climates, but major genetic reorganizations almost always take place in the small, peripherally isolated populations that form new species.

—STEPHEN JAY GOULD, "BUSHES AND LADDERS," EVER SINCE DARWIN: REFLECTIONS IN NATURAL HISTORY, 1977

Chapter 18

Fort Augustus, Loch Ness

Dripping wet, I slung my water-laden backpack over my shoulder and trudged up the banks of Loch Ness, True following me to the public rest rooms. Tourists gawked, and the locals laughed, and it was all I could do to avert my eyes.

Entering the men's room, I stripped down to my boxers, washed the peat from my skin, then squeezed the excess water from my clothes into the sink. With the exception of the specimen containers and vacuum-packed food supplies, everything else in my backpack was ruined, including my sleeping bag and change of clothing.

True opened his own pack and pulled out a few dry shirts and two pairs of wool socks, tossing one of each to me. "Put these on. We'll hitch a ride back tae Drumnadrochit wi' Brandy, then fill our bellies at the Clansman before startin' oot fresh in the mornin'."

"I'm not going back."

"Zack, ye cannae go on wi' nae supplies."

"Then lend me yours and you go back. I need to go on before I lose my nerve, and there's still the entire east bank to cover."

"It's too dangerous alone."

"I'll be fine."

"Yeah, I'm sure that woman who got hersel' killed said the same thing."

"I'll camp out in the Glendoe Forest for the night, keeping a distance from the Loch. We'll rendezvous in Foyers tomorrow around noon."