Intro to Life Flashcards
What are some hypotheses of how life began on earth?
Life began elsewhere and was transported to earth by chance
Life began around 3.5 billion years ago from complex sequences of chemical reactions that took place spontaneously (Miller-Urey experiment)
What are the two elements needed for life?
- The system needs to be able to replicate
2. Life needs to be separate from its environment
What is the Miller-Urey experiment?
Built an apparatus that simulated the presumed conditions of a primeval earth to test abiotic synthesis of carbon compounds.
What were the conditions of the Miller-Urey experiment?
A gaseous phase containing carbon, nitrogen, oxygen, and hydrogen
Electrical energy provided by spark discharge
Ambient temperatures between 0-100 degrees C
Sterile conditions to begin with (abiotic environment)
What were the results of the Miller Urey experiment?
Resulted in the formation of 23 amino acids
What are some clues that life originated in the ocean?
Biological fluids have salinity approaching that of seawater
Terrestrial organisms are mostly water by weight
Mammals are incubated in watery fluid before birth.
Why is the idea that life originated in the ocean significant?
Shows that conditions on earth’s surface were too extreme and inhospitable. More stable below ocean surface.
What are stromatolites?
Created by cyanobacteria they are layers in the ocean when dirt sediments mixes with carbon dioxide that’s been expelled from bacteria, water and minerals, all trapped in microbes.
Why are stromatolites important?
They are direct evidence of early life in the ocean.
Fossils
What are cyanobacteria and why is it important?
Blue-green algae
Considered the first photosynthetic organisms on earth
Likely responsible for the creation of earth’s oxygenated atmosphere.
What are hydrothermal vents?
Fossils in volcanic deposits in Australia.
Adapted to high temps from active deep vents.
What is diversity?
Measure of the different nature of all living things
What is evolution?
The gradual alteration of a species’ genetic makeup. Favors organisms that are better adapted to their environment.
