Chapter 5 & 6 Flashcards
what is so special about Ozone on Earth?
ozone protects us from UV rays and gives earth its stratosphere
why would it be significant if there was an ozone layer found on another planet?
it would mean that life must exist on that planet because the only explanation for existence of ozone layer is life as we know it! Ozone breaks apart when it absorbs UV photon into O and O2. Requires LOTS of O and O2 to replenish constantly destroyed ozone.
We know of NO geological or chemical process that can produce that much
oxygen. Only possibility we know of is LIFE AS WE KNOW IT!
what is a habitable zone?
the region around a star in which planets could potentially have surface temperatures at which liquid water could exist
what are the general properties for life on earth?
order, reproduction, growth and development, energy utilization, response to the environment, and evolutionary adaptation.
When/where did life form on earth?
Life on earth likely formed in the deep ocean, near volcanic vents around
what is a cell
the basic structure of all life on Earth, in which the living matter inside is separated from the outside world
what is the difference between mutation and evolution?
individuals mutate, species evolve
What/when was the Cambrian explosion?
The Cambrian was an explosion in genetic diversity that occurred around 540-500 millions years ago
What was the Miller-Urey experiment?
This experiment was performed to learn how organic molecules might have formed naturally on the early earth. They were successful in creating organic molecules but not life
It showed that the building blocks of life form easily and spontaneously under the conditions of early Earth.
What were stromatolites?
excrement fossils from ancient microbes
What is Carbon-based life?
Life that uses molecules containing carbon for its most critical functions. All life on earth is carbon-based
What are organic molecules?
Generally, any molecules containing carbon and associated with life.
could life have migrated to earth?
Yes, it is possible. Venus, Earth, Mars have exchanged tons of rock (blasted into orbit by impacts). Also, some microbes can survive in space for several years.
what is the tree of life?
it is a diagram of the biochemical and genetic relationships among different organisms; its three main branches are the three domains: bacteria, archaea, and eukarya.
cyanobacteria
photosynthetic bacteria thought to have been responsible for making most of the oxygen that gradually built up in Earth’s atmosphere. Therefore paved the way for more complicated life forms.
