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| This is an image of Darwin created by Sanna Dullaway, an artist from Sweden.She used Photoshop to add color to this image so we can imagine how things would look like at that time. |
In this
class we had a better understanding of the people who contributed to the
development of the evolutionary theory. We also took a look on how the process
of natural selection works and at the end we watched a video from National Geographic
called: “Darwin’s secret notebooks”. A very interesting overview of Darwin’s
voyage and how he went from believing on the fixity of the species to creating
the most detailed book discussing the evolution of the species.
First
important not is that the book we are using for this class, makes several
references to “bio cultural evolution”.
It’s important to understand that idea because it will be mentioned many more
times. This is an idea that the biological part of evolution goes together with
the cultural. Both walking together and influencing each other.
Before
jumping to the precursors of the evolutionary theory, it is important to
understand that the discovery of evolutionary principles started in the Western
world around 16th and 17th centuries and had a big influence by the scientific
knowledge at the time.
The scientific
revolution contributed to expand the history of the Earth. Naturalists at the
time would spend a great amount of time comparing data, observing nature’s behavior,
coming up with different theories to contribute to change the mentality of a
time where people believed that everything around was created once and never
changed.
Some of the
people who were part of this process:
John Ray: concepts of species and genus and
believed that people shouldn’t just believe in what they read in books, they
should also go out there, observe nature and its behavior.
Carolus Linnaeus (Carl Linne): Created System Naturae which consists in an explanation of his system’s
organization: kingdom, class, order, family, genus and species. This is the
system we still use today.
George Louis Leclerc (Comte de
Buffon): Created a
44 vo. Encyclopedia describing the entire world, its origins and everything in
it. He believed that life was in constant change and therefore an idea of
evolution was already being planted.
Jean Baptist Lamarck: This man had great visions and was
very knowledgeable, but his theory at the time causes people to laugh at him
because it was really improbably. He believed that a certain species would
change their body parts during the life time, according to the needs of that
species to adapt the environment. Ex: Giraffes had long neck because they kept stretching
in order to reach for food. Moreover, Lamarck suggested that these new characteristics
would be passed on to the offspring of that species.
Erasmus Darwin: He was Charle Darwin’s grandfather. He
was researching at the same time as Lamarck, but expressed his theories and
beliefs through poetry.
George Cuvier:
Introduces the concepts of extinctions as a result of catastrophes.
Thomas Malthus: He argued for human populations and
its growth. He also thought about the fact that populations could only grow if
there was enough food supplies.
Charles
Lyell: Idea of uniformitarianism: Observed that geological processes that were happening
in the present had also happened in the past. He was a big influence of Darwin’s
work, as a matter of fact his book was on board beagle and was very helpful
source for Darwin.
James Hutton: Suggested that Earth had been
changing for long periods.
Charles Darwin: He was very interested in nature
since a little kid. He was one of six children, raised by his father and
expected to be a doctor like his father and grandfather, made he never made it.
He was sent to Christ’s College, Cambridge to study theology. During this
period, his interest for nature grew and at the age of 22 he went on an
expedition around the globe aboard the Beagle.
The trip took 5 years and it changed not only Darwin’s life, but also the
history of biological science.
When they
set sail, Darwin believed in the fixity of species, however, by the time they
got back, he was certain about the evolution of species. After that he took a
long time writing the book that was published in 1859, Origin of species.
One
important element that helped change Darwin’s mind, was the data he collected
in Galapagos islands. He realized some species (most specifically birds) shared
the same characteristics as birds seen in the lands of South America, but they
were somewhat different.
When he got back to England with the 13 different types of finches, he took the time to analyze his information and realized that the island finches were ancestor of the same type of bird found in the main land, but modified to adapt to the island habitats and dietary preferences, which was the reason for different beaks.
When he got back to England with the 13 different types of finches, he took the time to analyze his information and realized that the island finches were ancestor of the same type of bird found in the main land, but modified to adapt to the island habitats and dietary preferences, which was the reason for different beaks.
Alfred Russel Wallace: He suggested that the origin of new
species was due to the environmental factors. Species were descendants from
other species.
Natural
Selection:
Darwin
realized at the beginning of his research project, that there was a reason why
some species would survive and some wouldn’t. He came up with the idea that
those individuals with favorable variations would survive and reproduce and the
ones with unfavorable variations wouldn’t. Following is the explanations of
natural selection and how it works.
- Species can reproduce offspring faster than food increases;
- All species have biological variations;
- The number of offspring reproduce is larger than the number of offspring who can survive, so there is a competition between all of them;
- Favorable variations and traits is more likely to survive and reproduce;
- Environment determines if a variation or trait is favorable;
- Traits and variations are inherited and passed to next generation;
- New species can appear in long periods of time;
- Geographic isolation also affects the formation of new species.
Example of Natural Selection:
One famous
example of natural selection is the “peppered” moths around Manchester,
England. The variation of grey moths could camouflage on the trees during the
day and since the dark moth couldn’t camouflage, they were eaten by birds.
Therefore the dark moths reproduced less offspring that the grey variation, yet
by the end of the 19th century, the grey variation was almost completely
replaced by the dark one. This happened because of the industrialization in
England and coal dust covering trees around the area becoming more favorable
for the dark moth to camouflage so the grey variation ended up being the target
of birds.
Although
Darwin made a huge step in history, allowing us today to understand our origins
and how the evolution process takes place, there is still opposition to the
idea of evolution until this day. Science doesn’t always offer real answers
with absolute truths, so many people are still skeptical that evolution really
occurs.
Personal input:
First of
all, I would like to comment that I finally got my textbook and took some time
to take a look at it during the week. It’s a very interesting book and I am
looking forward to learn new things from it.
I also
realized my last post was very poor comparing to the journals I saw in the classroom
last night. So I hope from now one my blog posts are more complete and more
interesting with some more additional information in interesting subjects
relating to the class and book chapter studied.
This chapter
was quite interesting to me because I am very intrigued about human mind and
how some people are more influential to the world than others.
It was
interesting to take a look of what people believed at that time: we were all
created by one major power and we had not changed ever since. That idea seems so
out of cogitation nowadays, with the use of technology it becomes more and more
clear that all species evolve to better adapt to the environment they live.
I was also impressed
with the idea that back then, centuries ago, the naturalists started
researching based on very little information they had about animals, humans and
plants and really just focused in understanding why things were that way and
how did they get there and all the work they did at the time, still influences
us today. It is basically everything we know and how we see the world now.
I would love to play such an important role in the humanity, such as Darwin, but I believe we are now corrupted by technology, becoming lazy and doing what John Ray disagreed, reading things in books (or on the internet) and just believing it without going out there to make our own conclusions.
I would love to play such an important role in the humanity, such as Darwin, but I believe we are now corrupted by technology, becoming lazy and doing what John Ray disagreed, reading things in books (or on the internet) and just believing it without going out there to make our own conclusions.
I also loved
to see a bit more about Darwin’s expedition during the movie presented to the
class. It is really intriguing to image all the data he collect and all the
information he gathered about the places he had seen, with so little resources
at the time.
Additional
Information:
First
interesting thing I found was this website that has explanations about natural
selection evolution of species in a fun and easy way to understand. I played
the “survival game” and it is a good way to use as an example of how natural
selection works.
http://science.discovery.com/games-and-interactives/charles-darwin-game.htm
Secondly, I found this interesting website that is basically the beagle going around the globe interactively, with information of each place Darwin stopped.
Lastly, I added a brochure of Darwin's exhibit, organized by the American Museum of Natural History, New York, in collaboration with the Museum of Science, Boston; The Field Museum, Chicago; the Royal Ontario Museum, Toronto, Canada; and the Natural History Museum, London, England.
This brochure has pictures of the exhibit and some interesting facts that are covered.
