What Does Evolution Mean? Stephen Meyer Explains Three Different Claims — Transcript

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1. 0:00All right. Tell me what evolution means
2. 0:03because I people mean different things
3. 0:05by it it seems to me. So may maybe we
4. 0:07could just begin with a general
5. 0:10definition. Maybe the definition would
6. 0:11be good.
7. 0:11>> that is the right question to ask
8. 0:13because that's where the confusion
9. 0:14always starts is by not defining terms.
10. 0:17Okay. Um it's good classical philosophy,
11. 0:20you know, define your terms. Um
12. 0:23there are multiple meanings of the term
13. 0:25and that's where a lot of confusion
14. 0:26comes in. The most basic meaning of the
15. 0:28term evolution is simply the idea of
16. 0:29change over time.
17. 0:30>> Okay.
18. 0:31>> Do biological organisms change over
19. 0:32time? Yeah, sure they do. So that's not
20. 0:35controversial. No one is is disputing
21. 0:37that. There are different senses of
22. 0:39change over time within a biological
23. 0:41context. Uh you might be talking if you
24. 0:44when you're using this term in this this
25. 0:45kind of
26. 0:46rudimentary way, you might be referring
27. 0:48to the simple fact that the life forms
28. 0:52that exist on planet Earth today are
29. 0:54different than the ones that it existed
30. 0:56as best we can tell from the fossil
31. 0:57record on planet Earth a long time ago.
32. 1:00We do not have trilobites or
33. 1:01triceratopses today,
34. 1:03um but we we had triceratopses in
35. 1:07uh the
36. 1:09Jurassic, check me.
37. 1:11Cretaceous, one of those. And we had the
38. 1:13trilobites certainly in the in the
39. 1:15in the Cambrian period, okay? So so we
40. 1:17have life is different now than it is
41. 1:19today. It's changed over time. We've had
42. 1:21evolution. Okay. Fair enough. Not
43. 1:24controversial.
44. 1:25Um uh the other sense of evolution in
45. 1:29this um non-controversial sense is the
46. 1:32idea that there are small-scale
47. 1:34variations or adaptations of organisms
48. 1:37to their environment within various
49. 1:38usually within limits. You can think of
50. 1:41>> Yeah, give us some examples though.
51. 1:42>> Well, the famous examples are the ones
52. 1:44that are in the textbooks. The the
53. 1:45peppered moths,
54. 1:47the coloration of which shifted in
55. 1:49response to varying levels of
56. 1:51uh of atmospheric pollution in in in
57. 1:56industrial England. And dark to light
58. 1:58and like light and dark again. Um or the
59. 2:02the the the shape of the finch beaks
60. 2:05Darwin's famous
61. 2:06finches that whose beaks have changed
62. 2:10size and shape in response to varying
63. 2:13weather patterns and the availability
64. 2:15apparently the availability of of of
65. 2:17food supply. So different beak shapes
66. 2:19seem to favor survival of of certain um
67. 2:23of of when
68. 2:26harder or softer nuts were available. So
69. 2:28>> And then those that survived reproduce
70. 2:30and adapt.
71. 2:31>> and and right.
72. 2:32>> Okay.
73. 2:32>> And so you have a
74. 2:33>> Is this called microevolution?
75. 2:35>> It's called microevolution, it's called
76. 2:36adaptation, it's just called small-scale
77. 2:38variation within the limits of a
78. 2:40pre-existing gene pool.
79. 2:42It's well established. Nobody doubts it.
80. 2:45And so that's evolution number one.
81. 2:47>> Okay.
82. 2:47>> Evolution number two second meaning is
83. 2:50the idea that not only has there been
84. 2:52change over time but that change has
85. 2:54been continuous and effectively
86. 2:55unlimited. So that such that the best
87. 2:58way to depict the history of life is as
88. 3:00a great branching tree where the base of
89. 3:03the tree can be represented or
90. 3:05represents one or very few simple
91. 3:08organisms, maybe even one-celled
92. 3:09organisms that have morphed and changed
93. 3:12gradually to produce all the forms of
94. 3:14life we see today and the branches at
95. 3:16the top of the tree represent the forms
96. 3:18of life on planet Earth whether the
97. 3:20elephants or eggplants or or kangaroos
98. 3:23or all the wonderful things in all in
99. 3:25Aussie land, right? Down under. So So
100. 3:28and this is the idea of continuous
101. 3:30biological change over time and a single
102. 3:33tree of life is the is the the the the
103. 3:37image that best depicts the history of
104. 3:39life where the this axis is the time
105. 3:41axis, this axis represents morphological
106. 3:44form changes in form.
107. 3:46>> Now is this necessarily Darwinian
108. 3:47evolution or
109. 3:48>> It's part of Darwin's theory but not the
110. 3:50whole of it, okay? He had several
111. 3:52chapters in the origin just on the
112. 3:54argument for universal common descent.
113. 3:56Um the third meaning of evolution is
114. 3:58that there is an unguided undirected
115. 4:00process known as natural selection
116. 4:02>> Uh-huh.
117. 4:03>> acting on random variations if you're a
118. 4:05Darwinist, a classical Darwinist, or
119. 4:07acting on random mutations if you're a
120. 4:09more modern neo-Darwinist that has the
121. 4:13ability to produce all that continuous
122. 4:15change and that it does so without any
123. 4:18guidance or direction
124. 4:20>> What explains the mutations for that
125. 4:22kind of Darwinist?
126. 4:23>> Well, let's hold off on that for just a
127. 4:25second just to get the definition
128. 4:27straight. The the key thing is that is
129. 4:30that the the Darwinian argument is an
130. 4:33argument about the appearance of design.
131. 4:36And there are lots of Darwinian the
132. 4:37great Darwinian examples. He has one
133. 4:39with wolves and and and prey deer. I
134. 4:42think it's wolves and deer. The one I
135. 4:44like to use which is sort of an
136. 4:45adaptation of of a Darwinian argument I
137. 4:48just I like to use the example of of
138. 4:51sheep. Imagine you have some wool very
139. 4:53woolly sheep in the far north of
140. 4:55Scotland.
141. 4:56>> Mhm.
142. 4:56>> Okay, and you're a
143. 4:59and you want to breed a woollier breed
144. 5:00of sheep. What do you do?
145. 5:02>> Mhm.
146. 5:02>> You take the the woolliest males and the
147. 5:04woolliest ewes and you allow only them
148. 5:06to breed and then you repeat that
149. 5:08through multiple multiple generations
150. 5:10and cycles and eventually you'll get the
151. 5:12really woolly sheep that are kind of
152. 5:14like the ones that were in the
153. 5:14VeggieTales movies. You know, so woolly
154. 5:16they fall over. Um
155. 5:18but what's going on there? Well, that's
156. 5:20that's that's
157. 5:23what's called artificial selection.
158. 5:25There's an There's a the the the sheep
159. 5:28has been
160. 5:29certain attributes of the sheep have
161. 5:31been maximized because of the
162. 5:33intentional selection of the breeding
163. 5:36pairs by the by the rancher sheep
164. 5:38herder.
165. 5:39Now, what Darwin did was in effect say
166. 5:42Now, and if you're in a if you're in the
167. 5:43far north of Scotland, you got a very
168. 5:45woolly breed of sheep, you might have
169. 5:47bred something that has an
170. 5:49that's advantageous. It has as a an
171. 5:52attribute that helps it survive.
172. 5:54What Darwin said was
173. 5:56this was not his example, but it's mine,
174. 5:58but it's in same kind of reasoning.
175. 6:00Imagine
176. 6:02instead of selecting
177. 6:04the woolliest males and females each
178. 6:07generation, what if instead there was a
179. 6:09series of very cold winters
180. 6:12such that only the woolliest survived.
181. 6:15Now after 20 generations or whatever it
182. 6:18is, you're going to get the same
183. 6:19outcome, but there was no mind there was
184. 6:22no mind behind it. Instead of artificial
185. 6:24selection, now you have nature doing the
186. 6:28selection. Now you have natural
187. 6:29selection.
188. 6:30Now, how does that get rid of design?
189. 6:33Well, in the Darwinian way of thinking,
190. 6:35it gets rid of design because in the 19
191. 6:38well, in the 19th century, the one of
192. 6:41the most striking evidences of design
193. 6:42that was often cited by biologists was
194. 6:45the adaptation of organisms to their
195. 6:46environment. Fish live in the water and
196. 6:49they have they have fins and gills.
197. 6:52Birds live in the air and they have
198. 6:53wings.
199. 6:54Organisms seem to have the attributes
200. 6:56they need to survive in the environments
201. 6:58in which they lived and that to 19th
202. 7:01century and prior biologists seemed to
203. 7:03be an evidence that there had been
204. 7:05design in the placement of the organisms
205. 7:07in their environment. Well, now Darwin
206. 7:08comes along and he can explain
207. 7:09adaptation
208. 7:11without recourse to a designer, okay?
209. 7:15It's now nature doing the selecting. Now
210. 7:17you have a woolly breed of sheep in the
211. 7:19far north of Scotland
212. 7:21and you haven't had a a Scottish sheep
213. 7:24herder doing the doing the selecting.
214. 7:25It's been the winters, okay? And so now
215. 7:28we've explained design the at least the
216. 7:31the feature of design that attracted the
217. 7:32attention of a lot of 19th century
218. 7:33biologists without a designer. And so
219. 7:36this is often very puzzling to the
220. 7:37public when they hear Francisco Ayala or
221. 7:40Richard Dawkins talking about
222. 7:42biology as the study of complicated
223. 7:43things that give the appearance of
224. 7:44having been designed for a purpose, but
225. 7:46it's only the appearance. Why only the
226. 7:47appearance? Well, because there is this
227. 7:49unguided undirected mechanism of natural
228. 7:52selection acting on the on the random
229. 7:54variations to favor only those
230. 7:57variations which will confer survival in
231. 7:59a given environment.
232. 8:01So so far so good, okay? Now, what the
233. 8:03Darwinists do
234. 8:05is they say that that mechanism apply
235. 8:08can explain everything, okay? And what I
236. 8:10like to ask is, well, is that kind of is
237. 8:13that adaptation the only evidence of
238. 8:16design?
239. 8:17And if not, does the Darwinian mechanism
240. 8:20explain all the others?
241. 8:22Okay? It does a very nice job of
242. 8:24explaining small-scale variation and the
243. 8:27adaptations that ensue within a given
244. 8:29environment. Type one evolution, Yeah,
245. 8:31yeah, essentially it's exactly.
246. 8:34Um,
247. 8:35and what evolutionary even leading
248. 8:37evolutionary biologists are now
249. 8:39acknowledging is that the mutation and
250. 8:42we the selection and we can even bring
251. 8:44in mutations even if we just add in them
252. 8:46which is the
253. 8:47variations in the sequences of the A's,
254. 8:49C's, G's, and T's in the in the DNA,
255. 8:51random changes.
256. 8:52Uh, because that's now been posited as a
257. 8:54source of variation upon which natural
258. 8:56selection can act.
259. 8:58Um,
260. 8:59and what many even even leading
261. 9:01evolutionary biologists are are asking
262. 9:03is
263. 9:04can that mechanism produce
264. 9:07not just small-scale variation and the
265. 9:10adaptations that ensue from it, but can
266. 9:12they can that mechanism produce
267. 9:15large-scale morphological innovation,
268. 9:18fundamental
269. 9:19fundamentally new changes in form? And
270. 9:22there is a huge skepticism about that
271. 9:24certainly among those of us who are
272. 9:25proponents of intelligent design, but
273. 9:28even among leading evolutionary
274. 9:30biologists. There was a conference in
275. 9:312016 convened by the Royal Society
276. 9:36uh, in London, arguably the oldest and
277. 9:38most august scientific body in the
278. 9:40world, a group of evolutionary
279. 9:41biologists convened a conference to
280. 9:43explore
281. 9:44the need for a new theory of evolution
282. 9:47and the need for new mechanisms that
283. 9:49would have the creative power that
284. 9:51mutation and selection lack, something
285. 9:53that would complement that. One of the
286. 9:55conveners at the end of the conference
287. 9:57said that the conference was
288. 9:58characterized by a lack of
289. 9:59momentousness. In essence, the the talks
290. 10:03did a good job of characterizing the
291. 10:05problems
292. 10:06but did not come up with any solutions,
293. 10:09any new mechanisms that would have the
294. 10:11creative power that mutation and
295. 10:12selection lacks. And I haven't really
296. 10:14talked about some of the the evidence
297. 10:17that the that the mechanism lacks the
298. 10:18power, so we can do that. But but the
299. 10:20point is that it's widely recognized now
300. 10:23that the the mutation-selection
301. 10:25mechanism does lack creative power and
302. 10:28therefore there's something else is
303. 10:29needed to account for the origin of
304. 10:31genuine innovation in the history of
305. 10:33life.