Ornithology, Evolution, and Philosophy 123

More documents

Recommendations

Info

A Modern Unified Theory of Evolution 217 established by the naturalists (systematists), but it was Mayr’s clear and synthesizing discussion which convinced the geneticists and zoologists generally of the biological species concept and of the common occurrence of allopatric speciation: Either a previously continuous species range is split into two or more parts (through sea-level changes or climatic-vegetational changes) or a small isolated founder population is established by dispersal of a few individuals of a parental species across a barrier. Each isolated population then evolves independently, gradually diverging from one another. When sufficient genetic differences have accumulated, the parental and daughter populations may come in contact without hybridizing–a new (daughter) species has originated. Despite the striking gaps between the species of a local flora and fauna, the gradual evolution of new species was no longer a puzzle. There is no case in birds or mammals that would require sympatric speciation (without geographical separation of populations) and this may also be true for many, perhaps the majority of insect families (butterflies, Carabidae, Tenebrionidae, etc.). To appreciate the effectiveness of allopatric speciation one only needs to compare the high number of endemic species in island archipelagoes with the low number of such species in a continental region of comparable size. Mayr summarized the various stages of the differentiation process during allopatric speciation in his “dumbbell” model (1940c: 274–275, 1942e: 160) as follows [with some additions]; see Fig. 5.5: Stage 1: A uniform species with a large range; followed by Process 1: Differentiation into subspecies; resulting in Stage 2: A geographically variable species with a more or less continuous array of similarsubspecies(2aallsubspeciesareslight,2bsomearepronounced); followed by Process 2: (a) Isolating action of geographic barriers between some of the populations; also (b) development of isolating mechanisms in the isolated and differentiating subspecies; resulting in Stage 3: A geographically variable species with many subspecies completely isolated and some of them morphologically as different as good species [note that Stage 3 does not require Process 2b, only 2a]; followed by Process 3 (often in connection with 2): Development of intrinsic isolating mechanisms for genetical isolation, as well as the development of reproductive isolation and ecological differentiation, resulting in Stage 4: Expansion of range of such isolated populations into the territory of the representative forms; resulting in either Stage 5a: Noncrossing, that is, new species with restricted range or Stage 5b: Interbreeding, that is, the establishment of a hybrid zone (zone of secondary intergradation). During the course of time, isolated populations differentiate as members of the following microtaxonomic categories: local population-subspecies-speciessuperspecies-species group with numerous cases of intermediate differentiation
218 5 Biological Species and Speciation—Mayr’s First Synthesis Fig.5.5. Stages of geographical (allopatric) speciation (from Mayr 1942e, Fig. 16) found which were difficult to classify (see Table 4.2 on p. 177). However, such “intermediate” forms illustrated for Mayr the process of speciation graphically. Strictly speaking it is not the subspecies but the geographically isolated population which may reach species status. However, little was known about the genetic basis of the speciation process itself which both Dobzhansky (1937) and Mayr (1942e) felt certain occurred as a continuation of microevolution. In a superspecies the member species are not ecologically compatible, for which reason the respective species populations, if their ranges abut, compete along the contact zones and exclude each other geographically without (or only rarely) hybridizing. The closely related members of a species group may be sympatric in parts of their ranges. In ring species the overlapping populations are so strongly differentiated that they no longer hybridize and would be considered species if their direct intergradation through the “ring” of subspecies were to be interrupted (an example are the Asian greenish warblers Phylloscopus trochiloides, Irwin et al. 2005). According to the “Wallace-Dobzhansky model” isolating mechanisms of neospecies originate due to selection forces in sympatry, whereas according to the “Darwin-Muller-Mayr model” isolating mechanisms arise as incidental, pleiotropic by-products of divergence in allopatry (but see also under sympatric speciation, p. 223). David Lack (1944, 1949, 1971) added important data on ecological aspects of the speciation process, as acknowledged by Mayr (1982d: 274). Besides the “dumbbell” model of geographic speciation, Mayr (1942e) developed an alternative speciation model: a new species originates from jump dispersal of a few individuals forming a small strongly isolated peripheral founder population (founder principle, 1942e: 237; 1954c; 1963b: 539, 554; peripatric speciation, 1982l). This principle relates the reduced variability of small founder populations not to accidental gene loss, but to the fact that the entire population was started by a single pair, a few individuals or even by one fertilized female which contained only a fraction of the gene pool of the parent population. These “founders” carried
Page 1 and 2:
Jürgen Haffer Ornithology, Evoluti
Page 3 and 4:
Preface Ernst Mayr (1904-2005), emi
Page 5 and 6:
Contents Introduction 1 Part I The
Page 7 and 8:
Contents IX 2 Bibliography of Ernst
Page 9 and 10:
2 Introduction and speciation, the
Page 11 and 12:
4 Introduction (1928-1929) to repla
Page 13 and 14:
Ernst Mayr has been an observer all
Page 15 and 16:
The Family 9 court system. He had a
Page 17 and 18:
The Family 11 Fig.1.1. Family genea
Page 19 and 20:
The Family 13 where they learned La
Page 21 and 22:
Birdwatching 15 even finishing befo
Page 23 and 24:
Birdwatching 17 Fig.1.5. ErnstMayr
Page 25 and 26:
Birdwatching 19 Fig.1.6. Ernst Mayr
Page 27 and 28:
Birdwatching 21 he simply smoked ci
Page 29 and 30:
University Student in Greifswald an
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Friendships at School and Universit
Page 41 and 42:
2 The Budding Scientist PhD Thesis
Page 43 and 44:
TheInfluenceofTeachers 37 excellent
Page 45 and 46:
Erwin Stresemann—Teacher and Frie
Page 47 and 48:
Erwin Stresemann—Teacher and Frie
Page 49 and 50:
Assistant Curator at the Museum of
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Expeditions to New Guinea and the S
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Part II Ornithologist and Evolution
Page 101 and 102:
96 3 The New York Years (1931-1953)
Page 103 and 104:
98 3 The New York Years (1931-1953)
Page 105 and 106:
100 3 The New York Years (1931-1953
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
4 Ornithologist and Zoogeographer B
Page 147 and 148:
142 4 Ornithologist and Zoogeograph
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172: 166 4 Ornithologist and Zoogeograph
Page 189 and 190: 184 5 Biological Species and Specia
Page 221: 216 5 Biological Species and Specia
Page 247 and 248: 6 Life in North America during Worl
Page 249 and 250: 244 6 Life in North America during
Page 259 and 260: Part III Professor of Zoology at Ha
Page 261 and 262: 256 7 The Harvard Years (1953-2005)
Page 271 and 272: 8 Evolutionary Biology— Mayr’s
Page 273 and 274:
268 8 Evolutionary Biology—Mayr
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
284 9 Ernst Mayr—the Man his coll
Page 291 and 292:
286 9 Ernst Mayr—the Man addresse
Page 293 and 294:
288 9 Ernst Mayr—the Man undertak
Page 295 and 296:
290 9 Ernst Mayr—the Man unaware
Page 297 and 298:
292 9 Ernst Mayr—the Man His hand
Page 299 and 300:
294 9 Ernst Mayr—the Man Prize (1
Page 301 and 302:
296 9 Ernst Mayr—the Man the inte
Page 303 and 304:
298 9 Ernst Mayr—the Man I have s
Page 305 and 306:
300 9 Ernst Mayr—the Man Fig.9.4.
Page 307 and 308:
302 9 Ernst Mayr—the Man not mali
Page 309 and 310:
304 9 Ernst Mayr—the Man papers d
Page 311 and 312:
306 9 Ernst Mayr—the Man 2005. Me
Page 313 and 314:
308 9 Ernst Mayr—the Man Fig.9.5b
Page 315 and 316:
310 9 Ernst Mayr—the Man health i
Page 317 and 318:
312 9 Ernst Mayr—the Man person a
Page 319 and 320:
314 9 Ernst Mayr—the Man with a r
Page 321 and 322:
316 9 Ernst Mayr—the Man conceptu
Page 323 and 324:
318 9 Ernst Mayr—the Man the two
Page 325 and 326:
10 Systematics and Classification T
Page 327 and 328:
322 10 Systematics and Classificati
Page 329 and 330:
Page 331 and 332:
Page 333 and 334:
Page 335 and 336:
Page 337 and 338:
Page 339 and 340:
Page 341 and 342:
Page 343 and 344:
11 History and Philosophy of Biolog
Page 345 and 346:
340 11 History and Philosophy of Bi
Page 347 and 348:
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
Page 363 and 364:
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
376 12 Summary: Appreciation of Ern
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Acknowledgments Iamdeeplygratefulto
Page 389 and 390:
List of Abbreviations AAAS American
Page 391 and 392:
386 References Beehler BM, Pratt TK
Page 393 and 394:
388 References Cracraft J (2002) Go
Page 395 and 396:
390 References Haffer J (1997a) Ess
Page 397 and 398:
392 References Keast JA (1996) Avia
Page 399 and 400:
394 References Olson SL (1975) The
Page 401 and 402:
396 References Smith JJ (1936) Eric
Page 403 and 404:
398 References Wiglesworth LW (1898
Page 405 and 406:
Appendix 1 Curriculum Vitae (includ
Page 407 and 408:
Appendix 1 403 1978 Prêmio Jabuti,
Page 409 and 410:
Appendix 1 405 Society Offices Linn
Page 411 and 412:
Appendix 2 407 1926c Das Freibrüte
Page 413 and 414:
Appendix 2 409 1932 1932a Birds col
Page 415 and 416:
Appendix 2 411 1936g Melidectes bel
Page 417 and 418:
Appendix 2 413 1941e Birds collecte
Page 419 and 420:
Appendix 2 415 1944f Chromosomes an
Page 421 and 422:
Appendix 2 417 1947g On the correct
Page 423 and 424:
Appendix 2 419 1952e Six new subspe
Page 425 and 426:
Appendix 2 421 1954g The tail molt
Page 427 and 428:
Appendix 2 423 1958c Concluding rem
Page 429 and 430:
Appendix 2 425 in E. Mayr, Evolutio
Page 431 and 432:
Appendix 2 427 1964l Introduction [
Page 433 and 434:
Appendix 2 429 1967d Subfamily Pach
Page 435 and 436:
Appendix 2 431 in Acta Soc. Zool. B
Page 437 and 438:
Appendix 2 433 1974b The diversity
Page 439 and 440:
Appendix 2 435 1976m Evolution and
Page 441 and 442:
Appendix 2 437 Mankind 13:430; P.W.
Page 443 and 444:
Appendix 2 439 (1984) in Queen’s
Page 445 and 446:
Appendix 2 441 1984c Evolution and
Page 447 and 448:
Appendix 2 443 1987b The status of
Page 449 and 450:
Appendix 2 445 1990 1990a The Myth
Page 451 and 452:
Appendix 2 447 1992f Haldane’s Ca
Page 453 and 454:
Appendix 2 449 1995g The search for
Page 455 and 456:
Appendix 2 451 1999 1999a Thoughts
Page 457 and 458:
List of Books by Ernst Mayr 453 200
Page 459 and 460:
Coauthorship 455 Coauthorship In th
Page 461 and 462:
Appendix 3 457 (4) Systematics 1942
Page 463 and 464:
Index Achievements 379 Adaptation 2
Page 465 and 466:
Index 461 Faunas 164-165 Family 8-1
Page 467 and 468:
Index 463 Realism and education 372
show all

Ornithology, Evolution, and Philosophy 123

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?