14-3: Origin of Heredity

Hypothesis Testable explanation to a problem or a question

Theory Summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. It is valid as long as there is no evidence to dispute it. EX. Cell Theory and Theory of Continental Drift

Law Generalizes a body of observations Laws explain things, but they do not describe them EX. Law of Gravity

First Life Forms Role of RNA Amino acids linked to make a chain that could make shapes like ribozymes (early ribosome) which could replicate itself

First Life Forms - The First Cells Prokaryotes before eukaryotes 3 major trends all interrelated: Anaerobic  Aerobic Heterotrophic  Autotrophic Chemosynthetic  Photosynthetic

First Life Forms The First Eukaryotes Endosymbiosis Theory Mitochondria and chloroplasts are thought to be prokaryotic cells that were engulfed by a bigger cell Supporting Evidence: Both organelles contain their own DNA DNA is circular (like other prokaryotes) Can replicate on their own.

Put these in the order in which they are thought to have originated on Earth Anaerobic heterotrophic prokaryotes Aerobic eukaryotes Chemosynthetic prokaryotes Photosynthetic prokaryotes Answer: 1, 3, 4, 2

Sequence of First Cells Anaerobic Heterotrophic Prokaryotes Chemosynthetic Prokaryotes Photosynthetic Prokaryotes Endosymbiosis Occurs Here! Aerobic Eukaryotes Photosynthetic Eukaryotes

Discovery Education-How Life Formed on Earth

Class work Read Pages 287-290 Answer Questions 1-5 on page 290 Write out questions or embed in answer. Draw and label Endosymbiosis on page 290