Transcript WHAT IS DARWIN`S THEORY?

DESCENT WITH MODIFICATION
A Darwinian View of Life
AP BIOLOGY Chapter 22
Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006
WHO INFLUENCED
DARWIN’S THINKING
Linnaeus (classification)
Hutton (gradual geologic change)
Lamarck (species can change)
Malthus (population limits)
Cuvier (fossils, extinction)
Lyell (modern geology)
Darwin (evolution, nutural selection)
Mendel (inheritance)
American Revolution
1750
Wallace (evolution, natural selection)
French Revolution
U.S. Civil War
1800
1850
1900
1795 Hutton proposes his theory of gradualism.
1798 Malthus publishes “Essay on the Principle of Population.”
1809 Lamarck publishes his theory of evolution.
1830 Lyell publishes Principles of Geology.
1831–1836 Darwin travels around the world on HMS Beagle.
1837 Darwin begins his notebooks on the origin of species.
1844 Darwin writes his essay on the origin of species.
1858 Wallace sends his theory to Darwin.
1859 The Origin of Species is published.
1865 Mendel publishes inheritance papers.
Figure 22.2
Image from: AP BIOLOGY by Campbell and Reece
Image from:
http://www.ucmp.berkeley.edu/history/aristotle.html
Aristotle- (384-322 B.C.)
Species are fixed (unchanging)
BUT recognized similarities
Arranged life forms
on a scale of
increasing complexity
scala natura“scale of nature”
http://www.kheper.net/topics/greatchainofbeing/index.html
Image from: http://www.medusozoa.com/images/linnaeus.jpg
• Founder of TAXONOMY-1735
Science of grouping & naming
• Sought to discover order in the diversity of
life “for the greater glory of God”
(1707-1778) • Each creature was specialNO evolutionary link
• Devised classification system based on
morphology (form and structure)
Binomial Nomenclature:
Naming system that gives organisms a
two part scientific name- Genus species
Still used today
LINNAEUS’S SYSTEM
Nested hierarchy
Taxon = classification unit to which
organisms are assigned
Ex:
Panthera is a taxon at the genus level
Mammalia is a taxon at the class level
http://content.answers.com/main/content/wp/en-commons/thumb/d/d6/150px-Biological_classification_L_Pengo.svg.png
Kidspiration by Riedell
Image Sources: see end of show
Kids Prefer Cheese Over Fried Green Spinach
Kings Play Chess On Fat Green Stools
King Phillip Cried Oh For Goodness Sake!
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Carnivora
Family Felidae
Genus Panthera
Species leo
http://www.vetmed.wisc.edu/dms/fapm/personnel/tom_b/2004-lion.jpg
GENUS = group of closely related
species
GENUS = Ursus (Includes many kinds of bears)
Ursus
arctos
Ursus
maritimus
Ursus
americanis
SPECIES = unique to each kind of bear
http://www.macecanada.com/images/bears/kodiak_bear.gif
http://students.cs.byu.edu/~tole/Virtual%20Zoo/polar-bear.jpg
http://en.wikipedia.org/wiki/Image:Black_bear_large.jpg
Genus and species assignments
provide 2 part scientific name
Homo sapiens
Homo sapiens
Image from: http://www.earlylearning.ubc.ca/images/photo_baby.jpg
Modern Taxonomy
has added more Kingdoms
AND more levels (DOMAINS)
Linneaus only used 2 kingdoms
(Plants & Animals)
Domains are larger than Kingdoms and
are based on the differences in
ribosomal RNA
Ideas that shaped Darwin’s thinking:
http://upload.wikimedia.org/wikipedia/commons/2/28/Georges_Cuvier.jpg
George Cuvier –
Father of Paleontology
ANTI-EVOLUTONIST
Fossils are
remains of
extinct life forms
“CATASTROPHISM” boundaries represent floods,
droughts, etc. that destroyed
many species living at that time
Ideas that shaped Darwin’s thinking:
http://www.creationism.org/books/TaylorInMindsMen/TaylorIMMc03.htm
1795 –James Hutton
“GRADUALISM”
Profound changes can result
from cumulative effect of
slow but continuous
processes
Proposed that the Earth was shaped by
geological forces occurring over very long
periods of time, and is MILLIONS not
THOUSANDS of years old.
Ideas that shaped Darwin’s thinking:
1833-Charles Lyell
Incorporated Hutton’s ideas into
“UNIFORMITARIANISM”
Geological processes that
shaped Earth are still
operating at same rate.
Darwin read his book on
the Beagle voyage
http://www.biologydaily.com/biology/Sir_Charles_Lyell
MODERN GEOLOGY
http://wrgis.wr.usgs.gov/docs/usgsnps/animate/A08.gif
http://www.nndb.com/people/250/000024178/malthus.jpg
Ideas that shaped Darwin’s thinking:
Thomas Malthus (1798)
wrote essay on
population growth
Human suffering (disease, famine,
homelessness, and war) are consequences
to human population increasing faster than
food and other resources
http://www.educa.rcanaria.es/fundoro/00.corsi.htm
Ideas that shaped Darwin’s thinking:
Jean Baptiste Lamarck (1744-1829)
One of first scientists to recognize
that living things changed over time
and that all species were descended
from other species.
1809- Published his ideas about
“Inheritance of Acquired Characteristics”
the year Darwin was born
INHERITANCE OF ACQUIRED CHARACTERISTICS
The male fiddler crab uses its
front claw to attract mates and
ward off predators.
“USE or DISUSE” = Use it or lose it
Through repeated use, the front
claw becomes larger.
The fiddler passes on this
acquired characteristic to its
offspring
http://www.geocities.com/arnold_schwarzenegger_pictures/
What’s wrong with Lamarck’s hypothesis?
Lamarck didn’t know about
genes and how traits are
inherited.
Acquired traits are not
passed on to offspring
Or are they? . . .
New field of EPIGENETICS is exploring this
What’s right with Lamarck’s hypothesis?
Lamarck was first to
develop a scientific
hypothesis about
evolution and recognize
that organisms are
adapted to their
environment
http://pegasus.cc.ucf.edu/~he599900/giraffeeating.jpg
Slide by Kim Foglia@ http://www.explorebiology.com/
Who Was Charles Darwin?
In 1831, 22-year old Charles Darwin left England as
naturalist aboard the HMS Beagle for 5 year voyage
around the world.
Mission: Chart the South American coastline
Darwin noticed plants
and animals were different
from those he knew in Europe
Wrote thousands of pages
of observations and
collected vast number of
specimens
http://www.solarnavigator.net/history/explorers_history/HMS_Beagle.jpg
Who Was Charles Darwin?
Darwin spent a month observing life on the Galapagos
Islands
Each island has different rainfall
and vegetation and its own unique
assortment of plant and animal
species.
Biology by Miller and Levine; Prentice Hall Publishing©2006
http://mikebaird.com/ecuador/images/galapagos_off_ecuador_ng_map.jpg
Who Was Charles Darwin?
Although animals on Galapagos
resemble species on the
South American mainland,
many species were found no
where else in the world = ENDEMIC
http://www.darwinadventure.com/pictures/galapagos_giantortoise.jpg
http://www.destination360.com/south-america/ecuador/galapagos-animals.php
http://www.photoseek.com/galapago.html
DARWIN’S
FINCHES
Darwin collected 14 species of finches and
hypothesized that the Galapagos had be
colonized by organisms from the mainland that
had then diversified on the various
Who Was Charles Darwin?
After Darwin returned to England in 1836, he spent
years examining specimens he brought back from
voyage and filling notebooks with his ideas.
He did not rush to publish his ideas because they
disagreed with the fundamental scientific views of his
day.
In 1844 he wrote an essay describing his ideas and
asked his wife to publish it if he died.
http://www.elsie.brandeis.edu/images/journals.gif
In 1858 Alfred Russel Wallace, another
Naturalist working in the West Indies,
wrote an essay describing his work that
summarized the same ideas Darwin had
been thinking about for 25 years!
http://www.thesecondevolution.com/wallace&darwin.jpg
Suddenly Darwin had incentive to publish
the results of his work!
In 1859
On the Origin of Species
by Means of Natural Selection
presented evidence
and proposed a
mechanism for evolution
that he called
NATURAL SELECTION
http://www.loc.gov/exhibits/world/images/s125.jpg
Darwin’s Theory of Evolution
Darwin Presents his Case
Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006
Isn’t evolution “just a theory”?
In every day usage “theory” often refers to a
hunch or a speculation. When people say, “I
have a theory about what happened,” they are
often drawing a conclusion based on fragmentary
or inconclusive evidence.
The formal scientific definition of “theory” is
quite different from the every day meaning.
It refers to a comprehensive explanation of
some aspect of nature that is supported by a
vast body of evidence.
http://evolution.berkeley.edu/evosite/evohome.htm
Isn’t evolution just a theory?
In Science a theory is a well
supported, testable explanation of
phenomena that have occurred in the
natural world.
Example:
Cell theory
Atomic theory
Gravitational theory
http://www.avgoe.de/StarChild/DOCS/STARCH00/questions/apple_falling.gif
http://sixthsense.osfc.ac.uk/chemistry/atomic_structure2/atom.gif
VOCAB
ADAPTATION- Any inherited characteristic
that increases an organism’s chance of
survival
http://www.wildlife-traps.com/skunks.html
http://www.atomtigerzoo.com/photos/images/20060421233733_duckfeet.jpg
http://www.3kitty.org/travelrama/Photos/123-21-4x6.jpg
WHAT IS DARWIN’S THEORY?
OVERPRODUCTION of OFFSPRING
Capacity to over-reproduce seems
characteristic of all species.
http://www.biospheres.com/photogallery2ag/images/ladybugs_jpg.jpg
http://atthecreation.com/DEER/too.many.deer.jpg
WHAT IS DARWIN’S THEORY?
STRUGGLE FOR EXISTANCE means
that members of each species must
compete for food, space, and
other resources.
http://www.wasatchcomputers.net/gallery/elk_fight.jpg
WHAT IS DARWIN’S THEORY?
GENETIC VARIATION is found
naturally in all populations
Image from www.biologyzone.com
http://www3.nationalgeographic.com/animals/images/primary/zebra-herd.jpg
WHAT IS DARWIN’S THEORY?
Some organisms in a population are
less likely to survive.
http://www.cartoonstock.com/newscartoons/cartoonists/rrs/lowres/rrsn69l.jpg
VOCAB
Ability of an individual to survive and
reproduce in its specific environment
= FITNESS
http://www.cartoonstock.com/newscartoons/cartoonists/cga/lowres/cgan170l.jpg
WHAT IS DARWIN’S THEORY?
SURVIVAL OF THE FITTEST =
Organisms which are better adapted
to their environment tend to produce
more offspring than organisms without
those traits.
http://www.poster.net/bedard/bed202.jpg
WHAT IS DARWIN’S THEORY?
Over time,
NATURAL SELECTION
results in changes in the
inherited characteristics of a
population.
These changes increase a
species’ fitness in its environment.
How Does Evolution Really Work?
IMPORTANT TO REMEMBER !
•POPULATIONS evolve
NOT INDIVIDUALS.
•NATURAL SELECTION only
works on heritable traits.
•A trait that is favorable in one
environment may be useless or
detrimental in another.
WHAT IS DARWIN’S THEORY?
DESCENT WITH MODIFICATION
suggests that each species has
descended with changes
from other species over time.
This idea suggests that all living
species are related to each other
and that all species, living and extinct,
share a common ancestor.
http://groups.wfu.edu/ModelUN/images/Cover/Oranges.jpg
http://www.fx.clemson.edu/~ablank/126436919.Broccoli.jpg
http://www.butterball.com/en/images/plan_n_prep/preparing/carving1.jpg
THINK ABOUT IT
What do oranges, broccoli and
Butterball turkeys have to do
with EVOLUTION?
(Answers to come in this slide show!)
EVIDENCE OF EVOLUTION:
selection
1. Artificial
________________
Fossil record
2. ________________
Geographic Distribution
3. _______________
Anatomical homologies
4. _______________
Embryology
5. _______________
Molecular homologies
6. _________________
see Natural selection happen
7. Can
_______________
ARTIFICIAL SELECTION WORKS
Nature provides the variation through
mutation and sexual reproduction and
humans select those traits that they find
useful
EX: We have selected
for and bred cows to
produce more milk,
turkeys with more
breast meat, etc.
http://www.pp3moo.com/hm2cow.jpg
http://lazerbrody.typepad.com/photos/uncategorized/turkey.gif
WE’VE DONE IT WITH PLANTS
BIOLOGY by Campbell and Reece Prentice Hall Publishing©2005
WE’VE DONE IT WITH ANIMALS
If humans can
select for
beneficial traits,
why can’t nature?
If artificial selection
can achieve so much
change in relatively
short time, why can’t
major changes happen
over thousands of
generations?
http://www.windows.ucar.edu/earth/geology/images/dogs_sm.jpg
http://groups.wfu.edu/ModelUN/images/Cover/Oranges.jpg
http://www.fx.clemson.edu/~ablank/126436919.Broccoli.jpg
http://www.butterball.com/en/images/plan_n_prep/preparing/carving1.jpg
THINK ABOUT IT
Now you know what broccoli and
Butterball turkeys have to do with
evolution!
(Answers about oranges to come in this slide show!)
How Do We Know Evolution Happens?
The Fossil Record
provides evidence that
organisms have changed
over time.
http://www.bbc.co.uk/schools/gcsebitesize/img/bifossils.gif
If evolution has happened, we should be
able to find evidence of evolution in the
fossil record AND WE HAVE !
http://en.wikipedia.org/wiki/Image:Tiktaalik_BW.jpg
BBC Tiktaalik video
http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml
Lots of TRANSITIONAL FOSSILS have been found
Scientific American; Dec 2005; Vol 293; p100-107
http://evolution.berkeley.edu/evolibrary/images/news/tiktaalik_reconstruction.jpg
TIK-TAALIK
Intermediate between fish and early tetrapods
• Fins have basic wrist bones and simple fingers
• Earliest fish with a neck
• Discovered by Neil Shubin and Ted Daeschler in 2004
GEOGRAPHIC DISTRIBUTION =
BIOGEOGRAPHY
If Darwin’s theory is correct you would
expect to find closely related yet
different species living in a
geographic region as they spread into
nearby habitats and evolve.
That’s EXACTLY what we do see!
http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014608A.gif
GALAPAGOS FINCHES
The beaks of Galapagos finches have
adapted to eating a variety of foods
http://www.newtonswindow.com/problem-solving.htm
GALAPAGOS TORTOISES
Intermediate vegetation
Intermediate necks
Little vegetation
Long necks
Image from: BIOLOGY by Miller and Levine; Prentice Hall Publisher©2006
Lots of vegetation
Short necks
Tortoises adapted to different habitats as they
spread from the mainland to the different islands.
= DIVERGENT EVOLUTION = ADAPTIVE RADIATION
If Darwin’s theory is correct you would
also expect to find different species
living in far apart geographic regions
but similar habitats becoming more alike
as they adapt to similar environments.
That’s EXACTLY what we do see!
BOTH LIVE IN FOREST ECOSYSTEMS
Adapted to similar
environments, but
evolved independently
from different ancestors.
SUGAR GLIDER
in Australia is a marsupial
more closely related to
Kangaroos than North
American
FLYING SQUIRRELS
because
its ancestors were
marsupials.
http://www.flmnh.ufl.edu/fish/gallery/descript/TigerShark/scars.JPG
http://news.bbc.co.uk/2/shared/spl/hi/guides/456900/456973/html/nn1page1.stm
Whales and sharks have a similar body design
even though they are very different organisms
(one is a fish; the other, a mammal)
because they have independently adapted to
living in a similar environment.
= CONVERGENT EVOLUTION
HOMOLOGOUS STRUCTURESForelimbs of all mammals share same
arrangement of bones that can be
traced to same embryological origin
BIOLOGY by Campbell and Reece Prentice Hall Publishing©2005
EVOLUTION explains why certain
characteristics
in related species have an
Section 15-3
underlying similarity.
Turtle
Alligator
Ancient lobe-finned fish
Bird
Mammal
amnion /am·ni·on/ (am´ne-on) bag of waters; the extraembryonic membrane of
birds, reptiles, and mammals, which lines the chorion and contains the fetus and
the amniotic fluid
http://media-2.web.britannica.com/eb-media/27/117227-050-E1C9ABEE.jpg
http://medical-dictionary.thefreedictionary.com/amnions
VESTIGIAL ORGANS
Some homologous structures are vestigial and
have no useful function even though they are
still present.
Examples:
Hipbones and pelvis in whales and boa constrictors
Cecum (appendix) in humans
Skink legs
http://www.txtwriter.com/backgrounders/Evolution/EVpage12.html
Most mammals have a pouch
between their small and large
intestine that contains bacteria
to digest plants called a cecum.
In humans the cecum
is shrunken and unused.
It is our appendix
http://www.medicalgeo.com/images/appendix.gif
EMBRYOLOGY
Development of vertebrate embryos
follows same path
Image from:
http://calspace.ucsd.edu/virtualmuseum/litu/03_3.shtml
Same groups of undifferentiated cells develop in
the same order to produce the same tissues and
organs of all vertebrates, suggesting that they all
evolved from a common ancestor.
Image from: http://io.uwinnipeg.ca/~simmons/16cm05/1116/16anim3.htm
Why grow a tail and then lose it?
HUMAN EMBRYO
has a tail at 4
weeks which
disappears at 8
weeks
Pharyngeal pouches
become gills in fish,
parts of throat/ears
in humans
http://www.suite101.com/files/topics/6234/files/tail_HumanTail.gif
Nonfunctional legs in skinks
Why would an organism
possess organs without
function?
Why would an organism
grow a part and then
discard it?
If organisms evolved from ancestors in which that
part functioned, the gene code to make the part
would still be there even though it doesn’t work.
If the organ is not vital to survival, then
natural selection would not cause its elimination.
http://www.medicalgeo.com/images/appendix.gif
MOLECULAR HOMOLOGIES
• All life forms share same genetic
machinery (DNA & RNA)
• Universal genetic code
• Important genes share
highly conserved
sequences
Similarities in protein sequences
suggests similarities in DNA
Image from: Modern Biology by Holt, Rinehart, and Winston
MOLECULAR HOMOLOGIES
Similarities in
DNA and
protein
sequences
suggest
relatedness
Image from: BIOLOGY AP EDITION by Campbell and Reece; Prentice Hall Publishing©2005
Human- 46 chromosomes
Chimpanzee- 48 chromosomes
Similarities in karyotypes
suggest an evolutionary
relationship
Human: http://www.nationmaster.com/wikimir/images/upload.wikimedia.org/wikipedia/en/thumb/1/18/300px-Human_karyogram.png
Chimpanzee: Middle School Life Science , published by Kendall/Hunt.
Human- 46 chromosomes
Chimpanzee- 48 chromosomes
Even differences show relatedness
Chimpanzees have 2 smaller chromosome pairs we don’t have
Humans have 1 larger chromosome pair (#2) they don’t have.
Human: http://www.nationmaster.com/wikimir/images/upload.wikimedia.org/wikipedia/en/thumb/1/18/300px-Human_karyogram.png
Chimpanzee: Middle School Life Science , published by Kendall/Hunt.
PSEUDOGENES are vestigial genes.
EX: Humans have more than 99
different odor receptor genes, but more
than 70% of them are nonfunctional.
http://www.animationplayhouse.com/new/dogs2.html
http://unraveling.typepad.com/photos/uncategorized/nose_1.jpg
Slide by Kim Foglia@ http://www.explorebiology.com/
Can see Natural selection happen
EX: Changes in disease-causing microbes that
produce new organisms and new diseases.
Bird flu
_______
HIV
___
http://www.hhmi.org/askascientist/images/hiv.gif
Antibiotic-resistant
tuberculosis
__________________________
Why does evolution matter now?
http://www.hipusa.com/eTools/webmd/A-Z_Encyclopedia/tuberculosis.jpg
Researchers have developed numerous
drugs to combat HIV
– But using these medications selects for
viruses resistant to the drugs
Patient
No. 1
Patient No. 2
Patient No. 3
Weeks
Graph from BIOLOGY by Campbell and Reece
Slide by Kim [email protected]