0:07 today many of you will have heard of
0:10 evolution and natural selection but it
0:12 hasn't always been this way in the early
0:14 19th century scientists were still very
0:16 much in the dark as to how living things
0:19 evolved while the idea of evolution had
0:21 been around for a while the phenomenon
0:24 went unnamed and was without a proposed
0:26 mechanism until jean-baptiste Lamarck
0:29 had an idea Lamarque a zoologist noted
0:31 that animals seemed very well suited to
0:33 their environments and suspected that
0:35 throughout their lifetimes animals
0:38 improved themselves for example a
0:40 giraffes long neck was thought to be the
0:41 result of the animals continual
0:43 stretching in order to reach food that
0:50 Lamarque also thought that these changes
0:51 caused by the animals struggle to
0:53 survive were passed on to the next
0:55 generation which then continued the
0:59 evolutionary process in other words a
1:00 new baby giraffe would have a longer
1:02 neck as a result of its parent
1:06 stretching for their food for looking
1:07 into another theory of evolution a
1:09 little test for you according to
1:12 Lamarck's idea what would happen if two
1:14 animals that had spent their lives using
1:16 their right limbs far more than their
1:19 left limbs had offspring if you said
1:21 something similar to their offspring
1:23 would have had over developed set of
1:27 right limbs your right around two years
1:30 after Lamarck's death a young Charles
1:32 Darwin set off on a voyage that would
1:34 change his life and science forever
1:37 prior to setting sail on the HMS Beagle
1:39 Darwin had spent some time studying
1:42 under some of Lamarck's contemporaries
1:43 and thus had an understanding of
1:46 Lamarck's theories on inheritance what
1:48 he found on his voyage however did not
1:51 seem to fit with Lamarck's ideas instead
1:53 Darwin developed his own idea of descent
1:55 with modification the key difference
1:58 here is that in Darwin's idea the traits
1:59 of the parents were passed on without
2:02 being modified by the life of the parent
2:05 what Darwin realized was the importance
2:06 of the fact in any population of living
2:09 organisms there already exists variation
2:12 in any given characteristic as a result
2:13 he argued
2:16 nature would favor or select the fittest
2:19 variants this is natural selection by
2:21 Fitness Darwin meant the ability of an
2:23 individual to survive and to pass on its
2:26 characteristics to the next generation
2:29 over time changes in the characteristics
2:31 of a species could occur he also
2:32 proposed that the changes within a
2:34 species occurred very slowly through a
2:37 gradual process in the case of the
2:39 giraffe neck natural selection would
2:41 continually favor
2:43 giraffes with longer necks so that over
2:44 time the average neck length in the
2:47 population would gradually increase
2:50 following over 20 years of work
2:52 Darwin eventually published his idea of
2:54 evolution by natural selection after
2:56 another man named Alfred Russel Wallace
2:58 wrote him a letter saying that he had
3:00 thought of the exact same thing but
3:03 that's a story for another video if you
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