Evidence of Evolution
Four clues support the theory of
evolution
1. Fossil Evidence
• Fossils allow scientists to show how
species have changed over time.
Fossil of a dinosaur with feathers-an
ancestor of modern birds
We can trace animal evolution by looking at how the
fossils change.
Types of fossils
• Frozen in ice, trapped in amber, petrified,
cast and imprint fossils.
These
fossilized
human
footprints are
3.5 million
years old
What type of rock would most likely
have fossils in it?
Why aren’t fossils enough
evidence?
http://www.youtube.com/watch?v=GOKW_7KajCU
Peter Look- we’ve got ancestors! Finally! Proof
of Evolution!
Heck, this was back before we
even had bodies!
2. Anatomy
• Matching or extra/left over body parts support
the idea of common ancestors
2. Anatomy
• Homologous structures – body parts that
are the same or similar in different species
2. Anatomy
• Vestigial structures –body parts that are
useless or left over from a previous
ancestor in which they were useful
• Example: Appendix, tailbones, goose
bumps and wisdom teeth.
3. Embryology
• Many organisms have similar embryos,
supporting the idea of common ancestors.
http://www.thescientist.com/?articles.view/articleNo/
35052/title/Dinosaur-EmbryoGraveyard/
4. Biochemistry
• Many organisms
contain similar
sequences (sections)
of DNA.
• Small mutations or
changes in the DNA
eventually lead to the
evolution of new
species.
Chromosome #2 is split
into 2 separate
chromosomes in chimps,
but when combined, they
look just like our #2
Humans and chimps have
96% similar DNA.
Chimps have 48
chromosomes compared
to human’s 46.
http://www.youtube.com/watch?v=nvJFI3ChOUU
Human Fossil Evidence Found
http://abcnews.go.com/Technolo
gy/ardi-fossil-brings-us-closercommon-ancestorhumans/story?id=8716359
Click for a news story on new
human fossils found…
Quiz
• What are the four pieces of evidence
supporting the theory of evolution?
• Fossils, Anatomy, Embryology,
Biochemistry
Quiz
• What homologous
structure do humans
share with a cat?
• Similar skeletons
Quiz
• Name two vestigial structures that humans
have.
• Appendix, body hair, tail bones, goose
bumps, ear muscles, wisdom teeth, etc.
Quiz
• What is more closely related: a human and
a pig or a human and a fish? Why?
• Human and a pig, we share more
homologous structures, more DNA in
common, and our embryos are more
similar.
Homework
• Use Chapter 6, section 2 (starts on 165) to
complete the sentences on your
worksheet.