Genetics & Evolution

1
Genetics Evolution

• Chapter 19-25

2
Fact of Evolution versus Theory

• Fact We see organisms that have changed and
  continue to change in time
• Theory How does that change happen?
• Chemical Evolution
• Protein World
• RNA World
• DNA World

3
Darwin Evolution

• Natural Selection is a process whereby change
  over time may occur
• BOTH Punctuated Equilibrium and Gradual Change
  are now the more complete picture
• Species that are adapted to their environment
  survive, if the environment changes, they need to
  change as well or die
• The key to speciation is enough small changes
  added up over time and distance

4
Miller-Urey Experiment

• Simple gases (NH3, CH4, CO2, H2O, H2)
• Amino acids are produced
• Other conditions can lead to RNA!

5
Biological Evolution

• Lipids/RNA mixture formed micelle and bicelle
  structures
• Ones that could reproduce and use the membrane
  effectively simply out produced any other design
• First cell design thus affected all future cells!

6
Mechanism of Change

• Errors in DNA replication/translation/transcriptio
  n
• X-rays, Heat or UV Light causes DNA bases to bind
  to one another irreversibly
• Shifting of genotypes during sexual reproduction

7
Ecosystems Guide Evolution

• In general, where you live today may not always
  be the same
• As the environment changes so must organisms
  within it

8
Timetable of Evolution

• 4.5-2.5 Billion years ago cells appear
• 2.5-0.5 Billion years ago oxygen produced and
  eukaryotic cells replace simple prokaryotic cells
• 570 Million years ago animals begin to appear in
  fossil record
• 400 Million years ago land plants, insects

9
Timetable of Evolution

• 200-65 Million years ago Age of dinosaurs
• 65 Million years ago Mammals arise from ashes of
  extinction event
• 5 Million years ago Primates fairly closely
  related to us begin to appear in Africa
• 3 Million years ago Lucy!
• 200,000 years ago Homo Sapiens

10
Human Evolution

• Homo versus Australopithecus
• A. africanus versus A. afarensis
• H. erectus versus H. sapiens

11
Human Evolution