Evidence of Evolution
Target #9- I can identify the five types of
evidence for evolution
• Evidence for
evolution came
through fossils,
biogeography,
embryology,
anatomy, and
biochemistry
– Can be studied for information on environment
of the time, the age of the fossil
– Relative age of fossils was determined by where
they were located in the layers of rock
• The oldest fossils were on the bottom
– Some can consist of hard parts of organisms
• Shells
• Bones
• Teeth
– Soft parts can be preserved based off of how
the sample was preserved
– Trace fossils can be preserved
•
•
•
•
Trails
Footprints
Worm casts
droppings
Target #10- I can explain how fossils provide
evidence for evolution
• Fossils: the remains and traces of past
life or any other direct evidence of
past life
Example: Whale
Target #11- I can explain the purpose of a transitional
species
• Transitional species
– Fossils that serve as links
between groups
– Example: Archaeopteryx
• Lived 165 million years ago
• An intermediate between
reptiles and birds
– Had reptile-like features: jaws,
teeth, long and jointed tail
– Had bird-like features:
feathers and wings
– Other transitional groups
• Fish amphibeans reptiles
Example- Tetraphods
Target #12- I can
explain how
biogeography
provides
evidence for the
theory of
evolution
• Biogeography: the study of the
range and distribution of plants
and animals in different places
throughout the world in
comparison to the ancestors
– Organisms evolve in one locale and
then spread to accessible regions
– A different mix of plants and
animals will be present whenever
geography separates continents,
islands, seas, etc.
• Examples
– marsupials in Australia
– Lemurs in Madagasgar
– Mesosaurus in S.America & Africa
Example- Lemurs
Example- Marsupials
• The homology shared by
vertebrates extends to
their embryology
– All vertebrates have a
postanal tail and exhibit
paired pharyngeal pouches
• In fish and amphibians, those
pouches develop into gills
• In humans they develop into
various components of the neck
and inner ear
• Translation since both fish,
amphibians, and humans have
pharyngeal pouches, fish &
amphibians were the common
ancestor to all vertebrates
Target #13- I
can explain
how
embryology
provides
evidence for
evolution
• Anatomy
• Provides more evidence for the concept of a
common ancestor among all organisms
• Ex: forelimbs of vertebrate animals
– Analogous Structures: structures that
perform a similar function but are not
similar in origin
• Ex: wings of insects and birds
– Vestigial structures: remnants of organs or
structures that had a function in an early
ancestor
• Ex: snakes have pelvic bones and limbs but do not
walk
• Ex: human have an appendix that is believed to
have been used to process raw meat and plants
• Ex: hind limb bones exist in animals like baleen
whales and snakes
Target #14- I can explain how anatomy
provides evidence for evolution
– Homologous structures: features that are
similar in structure but appear in different
organisms and have different functions
Homlogous Structures
Analogous Structures
ExampleVestigial
Structures
• Almost all organisms use the
same basic biochemical
molecules
Target #15- I can
explain the
commonalities of
organism through
their biochemical
connections
– Includes DNA, ATP, and other
enzymes
– Organisms use the same DNA
triplet code for the same 20
amino acids in their proteins
• Humans share a large number
of genes with much simpler
organisms
– Life’s diversity has come about by
only a slight difference in many of
the same genes and regulatory
genes often found in introns and
other regions of the genome
• The more similar the DNA sequences
are between organisms, generally the
more closely related the organisms are
• Humans and chimpanzees are about 97%
similar
– Example protein:
• Cytochrome C used for the transport
of materials across the plasma
membrane in all organisms
– Humans vs. monkeys: 1 amino acid
difference
– Humans vs. ducks: 11 amino acid difference
– Humans vs. yeast: 51 amino acid difference
– Data is consistent with anatomical
similarities of the organisms and their
relation to each other
Target #15- cont.
– Example comparison:
Analyzing Data