I–28 INDEXSexual reproduction
introduction, 247–248, 249
reasons for, 263–268
selective interference and, 265–268
selfing and outcrossing, 269–270
Sexual selection
Darwin’s concept of, 251–253
defined, 60
by female choice, 257–259
flowering plants, 260
by male-male competition, 254–256
males and, 252–254
speciation by, 230
studying adaptations with the
comparative method, 422–423
Sexually antagonistic selection, 250, 304
Sexually transmitted diseases, 264
Seychelles warbler (Acrocephalus sechellensis),
260
Shavenbaby gene, 523 , 524
Sheep, 462, 561
Shelled protists. See Foraminiferans
Shoulder blade, 521, 522
Shrews, 408 , 461 , 527
Shubin, Neil, 448–449, 529
SI locus, 269
Siberian Inuit people, 556
Siblicide, 307, 308
“Sibling species,” 216
Sickle-cell anemia
balancing selection and overdominance of
the S allele, 120–122
genetic basis of, 81 , 85, 89
quantitative trait loci, 156
Siderophores, 302–303
Sierra Leone, 3, 421, 422
Signal transduction cascades, 377
Silene latifolia (white campion), 270
Silkworm (Bombyx mori), 346 , 561, 585
Silurian period, 434 , 444, 445 , 446, 447
Silverfishes (Zygentoma), 404, 450
Simian immunodeficiency viruses (SIVs), 3–4,
5 , 592
Simpson, George Gaylord, 16, 17 , 516, 541
Single nucleotide polymorphisms (SNPs)
defined, 82
quantitative trait loci and, 156, 157
Sinoconodon, 517 , 519
Sinodelphys, 458
Siphonaptera (fleas), 404, 450
Sirenia, 461
Sister groups, 33
Sister species
allopatric speciation and, 235–238
chromosome rearrangements, 224–225
defined, 216
sympatric speciation, 238–241
Sitta pusilla (brown-headed nuthatch), 216
Sitta pygmaea (pygmy nuthatch), 216
SIVs. See Simian immunodeficiency viruses
Skeletons, humans and chimpanzees
compared, 550
Skimmers, 387
Skin cancer, 115, 116
Skin colorconvergent evolution and, 557
evolutionary trade-offs and, 116
linkage disequilibrium with baldness, 196
parallel adaptation, 114–115
Skulls
chimpanzees and hominins compared,
553
diversification of amniote vertebrates,
454–455
in the evolution of mammals, 517–519
examples of decreasing complexity during
evolution, 540
humans and Neanderthals compared, 554
humans and other apes compared, 550
Skunk cabbages, 472
SLC22A4 gene, 563
Slime molds, 303–304
Slipper shell (Crepidula fornicata), 247, 287
Slobodkin, Lawrence, 219
Sloths, 408 , 461
“Slugs,” 296
Small populations, 168, 178
Smilisca clade, 486
Smilodon, 462
Smith, John Maynard, 17, 19 , 298, 539
Smut fungi, 346
Snails, 97 , 202
Snakeneck turtles, 510
Snakes
delayed reproduction, 283
evolutionary origins, 455
inbreeding load, 179, 180
jawbones, 55, 56
phylogenetic classification, 424 , 425
Snapping shrimps, 475
Snow geese, 160
SNPs. See Single nucleotide polymorphisms
Soapberry bug (Jadera haematoloma), 57
Soapberry family, 57
Soay sheep, 116–117
Social brain hypothesis, 558
Social Darwinism, 21, 593
Social evolution, 539
Social interactions
complexity in human society, 598
cooperation and, 296–297
in primates, 596
Sodium channels, 349, 352
Sodium–potassium pump, 49–50
Solanaceae (potato family), 380, 381 , 537–538
Solanum, 538
Solanum melogena (eggplant), 538
Solar system, 435
Solidago canadensis, 338–339
Soma, 94
Somatic mutations, 94, 591–592
Somniosus microcephalus (Greenland shark),
275
Songbirds, 98, 425
Sooty mangabey (Cercopithecus atys), 4 , 5
Sorex, 408
Sorex araneus (common shrew), 225
Sorghum, 560 , 561
South America, dispersal across the land
corridor with North America, 478South American marsupials, 460, 462
Southern beeches (Nothofagus), 477
Southern corn leaf blight (Helminthosporium
maydis), 333, 586
Soybean, 560
Sp gene, 388
Spadefoot toads (Spea), 155, 394
Spalacotheroids, 458
Spanish moss (Tillandisa usneoides), 472
Spatial patterns
clines, 192–193
evolution of dispersal, 204–206
evolution of species’ ranges, 207–208
gene flow, 193–196 (see also Gene flow)
genetic divergence between populations,
196–198
introduction, 191
Spea (spadefoot toads), 155, 394
Spea bombifrons, 155
Special creation, 578
Specialists, 288–291
Speciation
allopatric, 227, 235–238
in biological evolution, 18
causes of, 227–235
competition for resources and, 337
defined, 214
dispersal and, 477–478
distorter systems and, 311
ecological, 227–229
by genetic conflict, 228–230
genomics of, 242
geography of, 235–242
hybrid, 233–234
introduction, 213–214
parapatric, 241–242
phenotypic evolution and, 534–536
by polyploidy, 232–233
by random genetic drift, 234–235
reproductive isolation and, 220–227, 230–
232 (see also Reproductive isolation)
by sexual selection, 230
sympatric, 238–241
Speciation genes, 242
Speciation rate
lineage-through-time plots, 506–507
in models of change in diversity, 493
species diversity and, 504, 505
Speciation traits, 239–240
Speciation with gene flow
absence in allopatric speciation, 235
parapatric speciation, 241–242
sympatic speciation, 238–241
Species
in biological evolution, 18
definitions and concepts of, 215–219 (see
also Biological species concept)
diagnosing new species, 219
diversity in cichlids, 213–214
evolution of differences among, 181–183
evolution of ranges, 207–208
genetic drift and genetic variation within,
174–177
impact of global climate change on
ranges, 207–20827_EVOL4E_INDEX.indd 28 3/22/17 2:01 PM