Transcript Evolution - hudson.edu

Evolution
Evolution p. 369
•Inherited change in
organisms over
time
Definition: Evolution
• Scientific (more accepted now):
the change in the relative
frequency of alleles in a
population
Did Darwin ever use the word
evolution?
• NOPE
• He used instead
“descent with
modification”
Charles Darwin (1809-1882),
• In 1831, Charles Darwin sailed to
the Galapagos Islands in the HMS
Beagle.
• “Father of Evolution”
• Natural Selection
Alexander
Oparin
• proposed that life began in
the early oceans where a
rich "primordial soup" of
chemical compounds could
build up. He suggested that
energy from UV light and
lightening could form
these compounds.
Miller-Urey Experiment
Ammonia + nitrogen +
methane + hydrogen +
water + Voltage …after
some time amino acids
and organic
compounds (BUT
NOT LIFE)
VIDEO of Miller Explaining
the Experiment
http://www.ucsd.tv/millerurey/miller1.mpg
James Hutton:
The Father of Modern
Geology
• The earth had to be much more than a few
thousand years old (6,000) and more like
millions.
• (ie., lava pushed up land for volcanoes)
Charles Lyell
• Principles of Geology
• The processes that
occurred in the earth
in the past still occur
today.
Accepted Age of the Earth
• 4.5 - 4.6 billion years old
• LIFE AROSE
• 3.5 billion years ago
Lamarck (1744 -1829)
• theory of
inheritance of
acquired
characteristics
• FALSE
Why do Giraffes have long
necks?
Then according to Lamarck…
• Pass on longer necks.
• Or if you lift weights, your
children will be big-muscled!
• BUT…
So…Lamarck was wrong!
•Passed-on-traits must
be in the
chromosomes in the
sex cells
Malthus 1766-1834
Population would
outrun food supply,
leading to a decrease
in food per person.
Darwin’s 5 Year Journey
Darwin observed and collected
thousands of wildlife specimen
he had never before encountered.
Galapagos Islands
•
Galapagos islands
Stock Footage and
Video Clips. 39
Galapagos islands
videos and movies
available to search
from over 20 royalty
free motion brands.
H.M.S. Beagle
Galapagos: Off S.Am. Coast
Did Darwin know about genes?
•No
•So what he compared
were outward
characteristics
Main Ideas of Darwin
• 1. The mechanism of
evolutionary change was
natural selection (survival of
the fittest) –see Darwin’s
finches
Darwin’s
Proposed
mechanism for
evolution =
natural
selection
Artificial Selection
Bred to produce more meat Humans select
•
the variations
they find useful
Natural Selection
• Also “Survival of the Fittest”
• Individuals that are better suited to their
environment survive and reproduce most
successfully
Orchids fool
wasps into
"mating" with
them.
Natural
Selection
•“Survival of
the fittest”
Darwin's Theory of Sexual Selection
Natural Selection
• nature selected the best
adapted varieties to survive
and to reproduce.
• Video: Evolution: Library:
Evolution of Camouflage
Why is this natural selection?
• Which color beetles’ genes are more likely
to be passed on?
Natural Selection
• the driving force behind the
process of evolution.
• “Survival of the fittest”
Elk Rivalry Animation Elk Rivalry
• Describe how natural
selection works here.
• Opponents lock antlers
One extreme
phenotype is
most successful
Middle
phenotype is
most successful
Extreme
phenotypes
are most
successful
English peppered moths
• directional selection?
Does Natural Selection depend
• On genotype or phenotype?
• PHENOTYPE
VIDEO
• Evolution: How Does Evolution Really
Work? Click on Video for Students
Fitness
• Ability of an organism to survive and
reproduce in its specific environment
DESERT: Sleep
in cool dens
Adaptations
Inherited characteristics that increases
an organisms chance to survive
Big ears
dissipate heat
Leafcutter carries
50x’s its weight
Western Grebe Courtship
• Western Grebe Courtship Movie
In the “rushing” display, the
mating pair swim side-by-side
with their wings held back, their
long necks arched, and their
yellow beaks angled upward.
Take the Blue-Footed Booby
Blue-Footed Booby Adaptations
• 1. Large
webbed feet
to propel in
water at high
speeds
Blue-Footed Booby Adaptations
• 2. Body
and bill are
streamlined
Blue-Footed Booby Adaptations
• 3. Large
Tail to pull
them out of
a dive
Blue-Footed Booby Adaptations
• 4. Nostrils
close so in a
dive they won’t
get water in
their lungs
Blue-Footed Booby Adaptations
• 5. Specialized
glands to
manage salt
intake and
secrete oils
Chameleon: What adaptations?
Peacock LINK: Peacock Call
What adaptation did each beak allow
it to eat these foods?
Do Beak Lab
• What effect does the size and shape of the
bird’s beak have on the amount and type of
food it can eat?
Darwin
Agreed
with:
•every species since the
first cells emerged from one
common organism (probably some
bacteria) = Common Descent
Tree of Life
• Links all living things
Geologic Time
Scale
• BACTERIA
Common
Descent
Common Descent
• theory of universal
common descent = all
organisms on earth are
descended from a
common ancestor.
Darwin thought the Galapagos
finches descended from finches of
what country?
• Ecuador
We are more different than thought!
• Previous estimates of genetic similarity
between humans and chimpanzees
suggested they were 98.5–99% identical.
However, after the sequencing of the
chimpanzee genome 2005, the DNA
similarity was fixed at 96%.
• Nature, the Chimpanzee Sequencing and Analysis Consortium, which is supported in part by the
National Human Genome Research Institute (NHGRI), one of the National Institutes of Health
(NIH),
Factors Affecting Natural Selection
•
•
•
•
•
Food supply
Disease
Unable to mate
Weather natural selection
Fitness of organisms
Where to find fossils?
• Most fossils are
found in
sedimentary
rock.
• Examples of
sedimentary
rock are
limestone,
shale, and
sandstone.
Geologic
Column
Rod Sheldon:
Sedimentary
Layers)
Historical Record of Organisms
• Youngest (on top)
mammals/birds
• Next
• Next
• Next
• Oldest (on bottom)
reptiles
amphibians
fish
prokaryotes
Assume that
• Sedimentary rock is laid
down with the oldest rock
layer on the bottom and the
youngest rock layer on the
top
Which is the most probable
assumption about species A, B, and C
( In undisturbed rock layers)?
1. Species B is more abundant than species C.
2. Species C existed before species B.
3. Species A and B are genetically identical.
4. Species B descended from species A.
ANSWER
#2 Species C
existed before B
• When the industrial revolution
arrived in England, the
pollution had turned the bark of
the trees a much darker color.
Since light colored moths are
much easier for birds to see on a
dark background, they were
preferentially eaten.
Some say this is not true!
• 1. Moths fly at night (so color
would not be a factor).
• 2. Moths don’t land on tree
trunks; they hang on upper
canopy tree limbs.
• Secondary
sexual
characteristics:
color, size, etc.
different in
males and
females
Sexual
Dimorphism
Main Ideas of Darwin
• 2. descent with
modification
See “gradualism” and
“punctuated equilibrium”
Descent with Modification: Hawaii
honeycreepers
So…descent with modification
•Evolution is a
remodeling process
•Do you agree?
Darwin’s Ideas (cont.)
• 3. Living
species have
arisen from
earlier lifeforms
(common
descent)
Common Descent Theories
• Phyletic Gradualism
Punctuated Equilibrium
Phyletic Gradualism
• Gradual changes
• You would see transitional
fossils (in-between forms)
Transitional Fossils (in-between
forms)
Transitional Fossils
• The “missing link” or
transitional forms may
have features common to
both species
Punctuated Equilibrium
• Speciation can occur very
quickly, with long periods of
little change (equilibria) in
between.
• Proposed by Niles Elderidge and
Stephen Jay Gould
Compare These
Several origins
How do we get “proof” of our ideas
of evolution?
•
•
•
•
•
Fossils
Biogeography
Comparative Anatomy
Comparative Embryology
Molecular Biology
Fossils
• Imprints or
remnants of
organisms that
lived in the
past
Also find in Tar Pits
• One of best finds of Pleistocene (1.8
million to 11,000 years ago)
vertebrates in La Brea (Los Angeles)
Imprints (shape of organism
embedded in soft soil)
• Fern
Sycamore
More fossils
Fish
fossil
Crab
Horseshoe
Crab
• Often referred to as a living fossil
• has remained
unchanged for
approximately
500 million years.
Frozen Fossil
Australopithecus
afarensis
• Humans have much shorter
arms compared to their
legs than chimpanzees do,
and Lucy falls roughly
in the middle
Bones, teeth, shells preserve well
Leg bone of
amphibian
Jaw
bone
Horn
coral
shell
Petrified Wood
• Minerals dissolve in groundwater
seep into the tissues of dead
organisms and
replace
organic matter
Let’s Go...
Preserved: ice
The world's
oldest and bestpreserved
mummy (Oetzi),
believed to be
5,300 years old
Shark tooth
Preserved:
Amber fossil
• amber is the
pitch of
conifer trees
• This is a
95 million year
old fossil insect
Trace Fossils
• 1. Tracks
• 2. Trails
• 3. Burrows
• Dino Foot
Dinosaur Tracks (Colorado)
My Favorite
• Coprolite
• Petrified Poop (Dung)
Healed Wolf Thigh Bone
Weathering Has Exposed
Sedimentary Layers
• Utah
Lucy: Man or Ape?
Adult female - 25 yrs
About 40% of her skeleton
found
Her pelvis, femur (the upper
leg bone) and tibia show her
to have been bipedal.
About 107 cm (3'6") tall
(small for her species)
About 28 kg (62 lbs) in weight.
Where did Lucy get her name?
• When the bones were found, the
Beatles' song "Lucy in the Sky
With Diamonds" was playing
over during a night of dancing
and drinking.
Dr. Donald Johanson recollects
November 30, 1974, in Hadar, Ethiopia.
•
"I happened to glance over my
right shoulder . . .and there on the
surface of the ground was a little
bit of an elbow, I recognized it
immediately as belonging to a
human ancestor.” (good eyes?)
Not A Human
Arguments
• Lucy’s DNA found she was indeed
an ape (Cell magazine)
-few
skeletal bones which were
usually fragmentary and often
poorly preserved.
-bones
found far apart (1.5
miles away)
Other questions on Lucy
• Present day orangutan and
spider monkeys have the same
angle (pelvic and knees) as
humans yet are extremely adept
tree climbers.
And...
• Her brain size is still small, apelike in proportion
• The jaw, in particular, is distinct
in that it is V-shaped, totally
unlike human jaws.
Population
• Group of individuals of the
same species living in the same
place at the same time.
What is...
• The smallest unit that
can evolve?
•population
SPECIES
Similar -looking organisms that
breed with one another and
produce fertile offspring
SPECIATION
• Formation of a new species
Is a mule a
new species?
•+
Did Darwin know about…
•Genes?
• No
Homologous Structures
• Different Function but
Internal Anatomy is
similar means same
evolutionary origin
Biogeography
• Islands of the Galapagos were
geographically isolated and the
species of finches on these islands
were different, also.
Homologous Structures
Pterodactyl
Bat
Bird
Compare Evolution Theories
• MODERN
SYNTHESIS
• genes (alleles and
mutations)
• phenotypes
• populations (and
genetic drift)
•
•
•
•
DARWINISM
Organisms
Speciation
Individuals.
Homologous Structures
Bat
Mouse Human
wing forelimb arm
Embryology Compared
Haeckel’s Hoax
"ontogeny recapitulates phylogeny".
Real Embryos Compared With
Haeckel’s
Gills?
• In fact embryos never have true gills, and
calling features of human embryos 'gill slits' is
merely to read Darwinian theory into the
evidence.
•
•
•
•
•
•
•
Comparative Molecular Biology:
Number of Amino Acid
Differences with humans
Human 0
Gorilla 1
Gibbon 2
Rhesus monkey 8
Dog 15
Horse, cow 25
Mouse 27
DNA Cladistic Diagram
Molecular Biology
Homologies:
• Similarities in blood, proteins and
DNA and RNA sequences that
indicate species relatedness; the
greater the similarities, the more
closely related two organisms are
thought to be
•
•
•
•
•
•
•
Comparative Molecular Biology:
Number of Amino Acid
Differences with humans
Human 0
Gorilla 1
Gibbon 2
Rhesus monkey 8
Dog 15
Horse, cow 25
Mouse 27
So organisms
with similar
DNA or
proteins
would be
more closely
related
Darwinian Fitness
• Contribution an individual
makes to the gene pool of the
next generation relative to the
contribution of other
individuals
Gene Pool
• The total collection of all
genes in a
population
at one time.
Contrast
• Microevolution
• Macroevolution
• Changes
within a
• Species change
species
into other species
• EXAMPLE: • EXAMPLE:
humans are
reptile into a bird
getting taller
Microevolution
• Darwin did in fact observe
small changes, such as
changes in the size and
shape of finch beaks etc.
Macroevolution?
• Darwin never did see a finch
turn into an iguana or visa
versa (or any other such
major change).
• Major changes are theorized
to take millions of years.