Download Evolution - MrOwdijWiki

Theory of Evolution
Intro
• Today we are going to start a unit on evolution
• It is important to note that everything that we will be
discussing today in the classroom will be based in
biology and scientific principles
• In order to be respectful to all people’s beliefs and
ideas
• I would also ask you to stick to the principals of
biology
What is Evolution
• Has anyone ever heard
about evolution before?
• What is the idea of
evolution?
• Where have you heard
the term evolution
before?
What is Evolution
• Evolution is the change
over time of inherited
traits in a population
• It is a hotly debated
topic
• It is a relatively simple
definition, however it
has many different
aspects to it
History of Evolution
• Many years ago there were
different ideas of how the
organisms on planet earth
came to be
• People believed that
organisms always the way
that they currently saw
them
• They did not have the ability
to observe populations, see
interactions between
species or see other
ecosystems
History of Evolution
• Since people were so
used to the fact that the
world did not change,
many people were
skeptical of the new
ideas of evolution
• Many of the scientists
that believed the world
was slowly changing
were ridiculed, mocked
and/or punished
Jean Baptiste Lamarck
• Jean Baptiste Lamarck
was the first biologist to
propose the idea that
populations of
organisms change over
time
• His ideas were
considered radical for
the time that they were
introduced
Jean Baptiste Lamarck
• Lamarck had the idea
that most organisms
passed on their traits
based on use and
disuse
• He believed that
organisms changed over
time based on their use
and disuse of certain
characteristics
Jean Baptiste Lamarck
• A good example of this
would be a giraffe
• Lamarck would believe
that a giraffe originally
started out as a short
necked animal
• Over time the giraffe
stretched its neck to get
food
• Over time the giraffe
grew a longer neck and
passed it on to its
offspring
Disproving Lamarck
• While Lamarck had the
right ideas that organisms
change, he did not have
the right method of
change
• Just by using or not using
a trait does not ensure it
will be passed on to the
next generation
• A runt in a litter of
puppies would
demonstrate this
Disproving Lamarck
• Just because an
organism really wants a
trait and may use it
does not ensure the
trait will be passed on
• You can think about
several things in your
own life that may apply
Darwin
• However a few years
later in the 1830’s a
young biologist set sail
on a voyage on the HMS
Beagle
• Charles Darwin’s voyage
was one of the most
important events in
biology
Darwin
• He sailed around the
world for five years
making observations
where ever he went
• One place that had
particular impact on
him was the Galapagos
Islands
• It was there that he
started to form the first
ideas of evolution
Darwin
• http://www.joost.com/
36ziwbw/#/?noScroll=tr
ue&video_info=36ziwb
w
Natural Selection
• Darwin found on his
journey that certain
animals were better
suited for their
environments than
other animals
• Darwin found that some
of these animals were
better suited to survival
than others
Natural Selection
• Darwin believed that
certain animals were
better suited to survival
and that helped them
live and have offspring
• Those animals that lived
and had offspring would
be the ones that you
see in the world
• This idea was called
natural selection
Natural Selection
• Natural selection can
only happen when one
organism has an
increased chance to
spread its genes
• The probability that an
organism will pass on its
genes to the next
generation is referred to
as fitness
Natural Selection
• An organism that has an
increase in fitness have
a larger chance of
passing on their genes
• An organism that has a
decrease in fitness has a
smaller chance of
passing on their genes
Overproduction
• There are also several
other things that
Darwin noticed during
his travels that helped
form his opinion of
natural selection
• One of the things he
noticed was the
number of offspring
that were produced
Overproduction
• Most animals can
produce more offspring
than can survive to
maturity
• This means that some
of the offspring will die
when they are young
• The offspring that will
die are ones that will
not be passing their
genes on in the gene
pool
Overproduction
• The idea that some
offspring do not survive
to maturity and cannot
contribute their
combination of genes is
called overproduction
• Examples of this would
be wild octopus
• More octopus are
produced each year
than can survive
Genetic Variation
• Darwin also noticed
that within a population
there are a difference in
traits
• The difference in traits
creates a full range of
traits within a species
• This is easy to observe
in any population
Genetic Variation
• The range of traits
within a population
helps determine how
natural selection
proceeds
• Natural selection tends
to select for certain
traits and have certain
other traits die out
• The range in traits is
called genetic variation
Genetic Variation
• The range in traits allows
for a species to survive if
some traits are not
variable
• If deer with large antlers
are hunted and killed
easier, there will be deer
that have small antlers
that would survive
• If there were no variation
among deer, none would
survive
Insert Graph of Height
# Of People
1.2
1
0.8
0.6
# Of People
0.4
0.2
0
4' 3'' 4' 6'' 4' 9"
5'
5' 3" 5' 6" 5' 9"
6'
6' 3"
Adaptation
• Some of the variations
help an organism
survive in an
environment
• These variations tend to
become more frequent
in a population
• The more frequent that
trait is in a population,
the better chance that
population will survive
Adaptation
• A trait that makes an
individual more likely to
survive in an
environment is called
an adaptation
• Something like thick fur
in a cold environment is
a successful adaptation
• Something like thick fur
in a warm environment
is not a successful
adaptation
Adaptation
• Remember an
adaptation is a
something that is
passed down from the
parents
• Adaptations are not
something that is
spontaneous or planned
by the organism