Ch. 7 Flashcards
What elements make up 96% of the mass of living things?
Hydrogen, carbon, nitrogen, oxygen
Life on Earth uses how many of the 92 elements
25
Essential material for the survival of organisms
Amino acids
Liquid on a planet must be?
Abundant and remain liquid over a reasonable temperature and pressure range
Wide liquid range is good
Due to higher likelihood of remaining liquid through climatic changes
Advantages of water
Wide range in temperature, occurs naturally in all three phases, ice is less dense than liquid water, is a polar molecule
Three major features of the moon
Highlands, maria, craters
Maria
Cover 15-20% of Moon’s surface, lower lying dark areas, have far fewer craters than the other regions of the moon. Predominantly on the Earth-facing side
Highlands
cover 80-85% of Moon’s surface, higher regions of very old rock, heavily cratered
Crater’s indicate what?
The higher the crater density the older the surface
Craters on the Moon show
It’s never had an atmosphere or water to erode the craters
Why is Mercury not habitable?
No liquid water and very high surface temperature
Why is Venus not habitable?
High surface temperature and 90 times Earth’s atmospheric pressure, clouds of sulfuric acid
Why is Mars not habitable?
Too little atmosphere to allow liquid on surface and very harsh radiation
Why are Jupiter and Saturn not habitable?
Significant vertical wind structures, elements of life must be at the right altitude to enable life to develop
