( UNIT 01 ) Life & Classification Flashcards
What are the 8 characteristics of life?
1) Made of one or more cells
2) Displays organization
3) Grows and Develops
4) Reproduces
5) Responds to stimuli
6) Requires energy
7) Maintains homeostasis
8) Adaptations evolve over time
What is the theory of spontaneous generation?
- Idea that life arises from non-life.
Which scientist disproved the theory of spontaneous generation?
Francesco Redi
Theory of Biogenesis ? Who was it developed by ?
- Developed by Louis Pasteur
- Idea that only living organisms can produce other living organisms
Primordial Soup Hypothesis ( How was this theory supported? Who were the scientists who first experimented to prove it? )
- Early hypothesis suggesting that Earth’s early atmosphere and ocean had a mix of certain gases that could have synthesized organic molecules through simple reactions; Energy provided through the sun and lightening.
- Stanley Miller and Harold Urey.
- Simulated early earth’s atmosphere by sealing water and certain gases in a glass flask. By applying electrical sparks to the mix they created amino acids .
What were the first cells probably like?
- Prokaryotes ( a cell with no nucleus or other organelles )
Endosymbiont theory
- Developed by Lynn Margulis
- A theory explaining how eukaryotic cells evolves : prokaryote cells lived with/inside other existing cells and if their relationship was mutually beneficial , the prokaryotes may have develop into a eukaryotic cell’s current organelles.
Approximately when was the earth made and what were the conditions like?
- 4.5 billions years old
- Covered in lava and toxic gases
Describe the connection between the “heavy bombardment” and the beginnings of life.
- For 600 million years comets and asteroids pounded the earth.
- Scientists have found amino acids on these asteroids, and through experiments have proven that their impact on earth creates even more complex structures of molecules.
What types of bacterial structures were discussed in the Nova video and what do they tell us about early earth?
- Snotites and “Phlegm balls”
- Early organisms were able to exist within earth’s early atmosphere
- Bacteria living in harsher environments rely on toxic gas for energy.
What do stromatolites have to do with the first appearance of oxygen in the atmosphere? What specifically makes up the living portion of them that actually creates the oxygen?
- The Cyanobacteria that thinly covers the top solely makes up the living portion of these structures. Through photosynthesis, they produced oxygen.
If the Earth was created 24 hours ago, how long ago did humans first appear?
- Less than 30 seconds away from midnight
What were Hooke’s contributions to science?
- Discovered and gave cells their name.
- Published drawings of cells and other minute bodies.
Cell Theory
1) All living organisms are composed of one or more cells.
2) Cells are the basic unit of structure and organization of all living organisms.
3) Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells
Compound light microscope
- Consists of a series of glass lenses and uses visible light to produce a magnified image.
- Each lens in the series magnifies the image of the previous lens.
- Scientists stain cells with dye to see them better.
- Maximum magnification without blurring : 1000x
