Download Ch22 Darwin and Evidences for Evolution

Darwin and Evidences for
Evolution
Ch 22
Darwin Review
• What did he use as the mechanism for how
evolution occurs?
• What 5 observations did he make about
populations?
• Which can evolve, individual or population?
• How would Lamarck compare to Darwin on
Finches?
Evidences of Evolution
1. Direct observations about populations
– Finches or honeycreepers of HI
– Antibiotic resistance in bacteria (MRSA)
– Pesticide resistance
• 2. The fossil record
– Paleontologists discover changes over time,
extinct species and transitional species like the
tetrapods.
3. Homology- species with similar structures
that may have very different functions
Homologous Structures:
• Embryonic homologies
All vertebrates are very similar in early
development; they have tails and pharyngeal
pouches
• Vestigial Organs- remnants of structures that
were used by an ancestor but of no use to the
modern species
• Molecular homologies- shared DNA or amino
acid sequences
• *Convergent evolution- when organisms have
similar adaptations (analogous structures) to
deal with the environment but are not closely
related.
• 4. Biogeography- where species are found
– Endemic species are found only in one place
– Continental drift and tectonics explain the
similarities in species found close to each other
today.