Transcript Darwin`s Evidence for Evolution

Evidence for
Evolution
by
Natural Selection
2006-2007
Vocabulary
Analogous
Convergent evolution
Embryo
Homologous
Vestigial
What are the lines of evidence that
support Darwin’s ideas?…
Human Macaque Dog Bird
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Frog
Lamprey
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Evidence of Evolution
Darwin argued that life on earth has been
evolving for millions of years.
1. Artificial Selection
2. The Fossil Record
3. Geographical location
4. Anatomical evidence
5. Similarities in Early Development
6. DNA and protein similarities (newer
evidence)
What are the lines of evidence that support Darwin’s ideas?
Terminal
bud
Lateral
buds
Cabbage
1)Artificial selection
Brussels
sprouts
Leaves
Flower cluster
Kale
Cauliflower
Stem
Flower
and
stems
Broccoli
Wild mustard
Kohlrabi
Selective
breeding
the raw genetic
material (variation)
is hidden there
What are the lines of evidence that support Darwin’s ideas?
2) Fossil record
550
500
Body size (kg)
450
Equus
400
350
300
250
Merychippus
200
150
Mesohippus
Hyracotherium
100
50
Nannippus
60 55 50 45 40 35 30 25 20 15 10 5 0
Millions of years ago
The Fossil Record
Evidence for Evolution – The Fossil Record
The Fossil Record
 Showed that:
There have been countless species that
have lived on earth but no longer live on
earth today
 Layers of rocks with fossils demonstrated
that thousands, or even millions of years
were needed to create this
 Species have changed in appearance and
complexity

The fossil record
The giant sloth
Evolution of birds
 Archaeopteryx


lived about 150 mya
links reptiles & birds
Smithsonian Museum,
Washington, DC
Evolution of land animals
 2006 Fossil Discovery of Early Tetrapod
“Tiktaalik”
 “missing link” from sea to land animals

 from swimming (0 legs) to walking (4 legs)
3. Geographic Distribution of Living
Species
 Animals that are related to each other showed
‘descent with modification’ based on their
environment (even though probably closely
related, looked different because different
environment
 Animals that were not related to each other
looked similar if they were from similar
environments.
Geographic Distribution of Living Species
Example: Based on what they look like:
Which two animals do you think are more
closely related to one another?
Desert Fox
Koala
Dingo
Geographic Distribution of Living Species
•Believed to not be closely related to each other even
though they look more alike.
•Evolutionists say they look alike because they live in
the same kind of environment so over time they adapted
in similar ways
Desert Fox
Dingo
Analogous structures
Convergent
Don’t
be fooled
by evolution
their looks!
Those fins & tails
& sleek bodies areDoes this mean
analogous structures!they have a
recent common ancestor?
Dissimilar anatomy doing a similar function
Convergent evolution
marsupial
mammals
These animals
look very similar but does
that mean they have a
recent common ancestor?
What is this
evidence of?
placental
mammals
What are the lines of evidence that support Darwin’s ideas?
4) Anatomical evidence
Homologous Structures
 Arms, wings, legs, and flippers all have very
similar bones
 Similar in anatomy doing different potentially
different functions
 Darwin believed this was evidence that all
species were original descended from one
common ancestor.
Homologous structures
spines
leaves
succulent leaves
needles
colored leaves
tendrils
Vestigial organs
Humans
Appendix
Coccyx
Wisdom Teeth
Darwin’s Tubercle (ear)
Palmaris Longus
Goose bumps
Pseudogenes – L-gulonolactone oxidase
These are
Whyremnants
would whales
of
have
pelvis
&
leg
bones
structures that were
if they
were always
functional
in
sea
creatures?
ancestral
species
Vestigial Organs
Humans
Appendix
Coccyx
Wisdom Teeth
Darwin’s Tubercle (ear)
Palmaris Longus
Goose bumps
5. Similarities in Early Development
Looking at the
embryonic
development of
organisms Darwin
noticed some
similarities that other
scientists also noticed.
Evidence for Evolution - Comparative Embryology
Why do embryos of different animals pass
through a similar developmental stage?
6. Putting it all together with DNA evidence
Human
Macaque
Dog Bird
Frog
Lamprey
The sequence in
DNA
proteins
Why &compare
is a &molecular
DNA
proteins
record
of evolutionary
across
species?
relationships.
Comparative hemoglobin structure
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Why compare
these genes?
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compare common genes
Number of amino acid differencesbetween
hemoglobin (146 aa) of vertebrate species and that
of humans C (respiration)
 cytochrome
 hemoglobin (gas exchange)
Building “family” trees