Transcript Evolution

Evolution
GIANT MISCONCEPTION
MAN DOES NOT COME FROM APES.
WE SHARE A COMMON ANCESTOR.
What is the theory of EVOLUTION?
• Scientific explanation vs. Religious
explanation
• Different theories of evolution exist. In this
class we will only focus on the scientific
theory. You are a free thinking individual
and have the right to believe in the theory
of your choice!
Evolution
• Evolution is a change over a
period of time.
• Evolution is the process by which
modern organisms have
descended from ancient
organisms.
Lamarck’s Theory of Evolution
• In 1809, Lamarck
proposed that by
choosing to use, or not
use, an organ, different
organisms acquired or
lost certain traits over
time. These traits could
be passed on to
offspring; and in this
process a species
changed over time.
A closer look at Lamarck
• Principle of Use and Disuse – organisms
can control and change their size and
shape by using their bodies in different
ways.
By trying to use their front limbs
for flying Birds eventually
changed limbs into wings.
A closer look at Lamarck
continued…
• Principle of Acquired Traits – the
concept that acquired characteristics
could be inherited.
During its lifetime
an animal somehow can
change its body structure
According to Lamarck if you spend
your life lifting weights your children
will have giant muscles too!
Yeah!
Pump it UP
Charles Darwin – the man, the
myth, the legend!
• Born in England in
1809 Darwin set sail
on an adventure that
would change the
world of science!
• He is considered the
“father of evolution”
H.M.S. Beagle
Some of Darwin’s Questions
• Why are there no rabbits in Australia when
the environment is perfect for rabbits?
• Why are there no kangaroos in England?
• Why do fossils sometimes resemble
species that are still alive?
Glyptodon
Fossil
Armadillo
Saddle back tortoise –
Hood Island, Galapagos
Dome Shelled Tortoise – Isabela
Island, Galapagos
Beaks of Finches
• Darwin noticed 14 different beak shapes in
the finches he saw on the Galapagos
• The beaks seemed well adapted to the
available food sources on the different
islands.
Flightless cormorant
• Only found on two
of the Galapagos
islands.
• Only 800 pairs left
• Lost ability to fly
Blue Footed Booby Video
• http://media.pbs.org/ramgen/odyssey/2000
0713_video.rm?altplay=20000713_video.r
m
Putting Darwin’s Ideas Together
• Darwin did not
complete his
conclusions about
evolution until 29 years
after he began his
journey to the
Galapagos
• He summarized his
findings in his
revolutionary book,
THE ORIGIN OF
SPECIES in 1859
Darwin’s Theory of Evolution
• Natural Variation - there are differences
among individuals within all species
Darwin’s Theory of Evolution
• Evolution by Natural Selection
–Struggle for existence
–Survival of the fittest
The Struggle for Existence
• Members of each species regularly
compete for food, living space, and other
necessary resources.
Stronger male lions are more likely
to get food, protect their range, and
have a pride of females ready and
willing to mate!
Survival of the Fittest
• Fitness – the ability of an individual to
survive and reproduce in its specific
environment
• Adaptation – fitness is a result of
adaptation, or inherited characteristics that
increase an organism’s chance of survival
and increases the chance of reproducing
What happens when a species
is does not have an adaptation
that is necessary to its
environment?
EXTINCTION
Peppered vs.
Non-peppered
Moths
• After the industrial
revolution in
Europe, soot
covered many of
the trees in
industrial areas.
Which moth do you
think is most fit for
the soot covered
tree environment?
Green vs. Brown Grasshoppers
Types of adaptations
• Camouflage – ability to blend in with one’s
surroundings
Countershading
Mimicry
Hazard colors warn predators that
they are toxic!
Poisonous Coral Snake
Poisonous Berries
How do we get these adaptations?
• Adaptations occur when there is a genetic
mutation in an organism’s DNA
• Sometimes the mutation is favorable, or
helpful.
Darwin’s Evolution
• Common Descent – all living things share
common ancestry
• Man does NOT come from apes, but man
and apes share a common ancestor
Evidence of Evolution
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Fossil Record
Geographic Distribution
Homologous Structures
Vestigial Structures
Analogous Structures
Embryology
DNA evidence
The Fossil Record
• Fossils that formed in rock over the course
of time are evidence that species have
been gradually changing for millions of
years.
Geographic Distribution
• How could finches on different
islands be so different than
finches from the mainland?
Homologous Structures
• Homologous Structures –
different body parts from
various species have different
functions yet are composed of
the same bones and all stem
from the same embryonic cells
Homologous Structures
Vestigial Structures
• Vestigial structures / organs – a structure
or organ that has no function
• May be evidence that the structure was
useful to a common ancestor
Vestigial Structure in Whales
Structures that were thought to be
vestigial. We now know the function of
some structures.
Analogous Structures
• Structures that share the same function
but is NOT derived from a common
ancestor
Embryonic Evidence
• In the early
embryonic
stages of
development
many
vertebrates
(animals with
backbones) are
so similar they
are difficult to
tell apart.
DNA Evidence of Evolution
• Humans and Bonobos share 98.4% of the
same DNA
Cladograms-diagrams that show
evolutionary relationships
SIMPLE TO COMPLEX
• In general, simple organisms
evolve into more complex
organisms.
Punctuated Equilibrium/Evolution
• States that evolution of species occurs
very abruptly. Cladograms have abrupt
right angles on branches.
Gradualism
• Cladograms show that evolution of
species occurs over the course of a long
period of time
Currently gradualism is the
accepted theory of evolution