Transcript Slide 1

Evidence of
Evolution
Unit 3-4 Notes
Mr. Hefti – Pulaski Biology
Here are 6 of the most
compelling forms…
1. Fossils
• Most complete form of evidence
• Sedimentary rocks form layers that
preserve outlines or remains of organisms
for millions of years
Sediment layers preserve order
Horse evolution as told by
fossil record
2. Geographic distribution of
organisms
• Organisms have specific environmental
requirements
• Some organisms possess limited ranges
3. Comparative anatomy
features
A. Homologous structures
- Similar structures that serve different
functions
3. Comparative anatomy
features
B. Analogous structures
- Different structures that serve the same
functions
3. Comparative anatomy
features
C. Vestigial structures
- Structures that now serve no apparent
function (but did at one time)
4. Similarities in embryonic
development
• All vertebrate organisms look very
“tadpole-like” early on in their development
due to a common set of
genes controlling early
development
- Homeobox genes
5. DNA similarities
• All living things possess DNA that carries
their genetic code
• Unicellular bacteria and multicellular trees
possess unique combinations of A, T, C,
and G
6. CHON
• All living things include these 4 elements:
– Carbon
– Hydrogen
– Oxygen
– Nitrogen