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Lecture 3

PSY352H5 Lecture Notes - Lecture 3: American And British English Spelling Differences, Gregor Mendel, Mechanical Engineering


Department
Psychology
Course Code
PSY352H5
Professor
Robert Gerlai
Lecture
3

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Friday, January 24, 2014
Animal Psychology: Lecture 3
CHARLES DARWIN’S THEORY OF EVOLUTION
-when we compare with animals, we are not the ones with the biggest brain, but on the
other hand synapse and the connections among neurones make us intelligent, but not
the size of brain. There is 10-15% of bacteria from our weight. Another way how to
see whether the specie is successful, you can also look at the place where they live,
for example bacterias live almost everywhere, they can withstand any kind of
conditions - they live on the top of the mountains, inside of species, under the earth.
So as we can see, we are not the greets specie, we just think it because we have
intelligence, we are not only one that are unique, every specie is unique.
-according to Darwin’s theory we are very similar to other species, and thats why we
are not the only one special but all species are special. There is evidence that even
simple vertebrates such as fish can feel and suffer pain, maybe not in the way we do,
but they do anyway. So we are not more special than other animals.
-from the genetic viewpoint, by looking at DNA researchers found that we are only
1.5% different from chimpanzees & also we are 70% similar to fish even thought there
is more than three millions of years between their and our evolution (measuring it by
getting chimpanzees DNA and human DNA and dividing the strands and trying to put
strand from each organism together and see how they fit which will allow us to
compare how similar they are, between us and chimpanzees there are only couple
spelling differences, but if we compere s to rats there are much more differences)
-according to Darwin we are united to any other form of life in our planet
EVOLUTION
-Darwin: Species change with time, revolutionary idea of his time, still attracts attention
in politics (USA). The process of natural selection.
-Evolution is not about species, it is about how individuals can produce more or less
offsprings, there is no specific direction, it is not about betterment of species, but it is
about individual, the result of the evolution is change of species, but the process of
evolution is not about species but about competition of genes represented by
individual, species are only byproduct of evolution. The goal of evolution is not to
create better adapted species, BUT it is about individuals with genetic variations
getting selected to produce more offsprings for the next generations
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Friday, January 24, 2014
-Species appear to change over time. Change often reflects adaptations to natural
surroundings. There is an overproduction of offspring and not all of the offspring will
survive. Only the best “the fittest” will make it. Thus, there must be selection for
certain characteristics and against certain other ones.
-PURPOSELESS CHANGE RESULTING FROM RANDOM VARIATION: it is
purposeless because it does not have any direction in mind, it does have not goal, it
is just happening by itself. It is not a thing, the direction of evolution is based on
random genetic selection where some individuals enjoy advantage but other not. It
looks like it is moving in one direction BUT in reality evolution proceeds in any kind of
direction.
-Darwin did not know genetics and was unaware of the work of his contemporary,
Gregor Mendel, the Austrian monk.
-Now we understand that mutation (and genetic recombination) is the bases of
variability upon which natural selection works. Genotype is important, it is what is
sent to the next generation by reproducing new offspring
-Fitness is defined as the number of viable offspring that reach reproductive age,
in other words, fitness is about how many genes an individual can successfully
pass onto the next generation. Fitness is not (although it can be), about physical
fitness. In other words, passing genes to the next generation can be solve in
numerous different ways.
-an individual that possesses a variant of a gene (an allele) that helps the
individual to pass this allele to the next generation is “fit”, and thus this allele will
be more frequent in the next generation. In other words, evolution is a change in
allele frequencies from generation to generation.
-Evolution leads to change in the distribution of phenotypical values from one
generation to the next. There are more ways of evolution:
Direction Selection ->
Ambidirectional (Stabilizing) Selection -> <-
Disruptive Selection: most frequent mode of the population would be selected
-WHY DO WE SAY THAT EVOLUTION HAS NO PURPOSE? It seems that organisms
become better and better with time (ex. that evolution is building an ever improving
system). It seems that the purpose of evolution is the betterment of the species (ex.
making more intelligent animals, enabling them to fly, run, swim, jump better…) BUT
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