Life in the Universe exam 2

6 key properties

order, reproduction, growth/development. energy utilization, response to environment, and evolutionary adaption

order

life is non random, a necessary but not a sufficient condition

reproduction

necessary for life to survive the death of individual

heredity

the passing of traits from parent to offspring via DNA

growth/development

all life goes through this, not sufficient but necessary for life

energy utilization

life maintains order and survives by having an external source of energy from the environment around it

first law of thermodynamics

law of conversation of energy

second law of thermodynamics

left alone, a system will tend to disorder

life

something that can reproduce and evolve through natural selection

evolution

“change with time”

overproduction

producing more offspring then the environment can support

competition for survival

resources are limited

individual variation

individuals of the same species have different heritable traits

unequal reproductive success

those whose traits are best for survival enable them to survive and. reproduce

natural selection

advantageous traits will win over time

cells

living matter separated from “outside”

cell similarities

pass hereditary information via DNA and same basic components for building cells

carbon

not the most abundant element but forms the backbone of organic molecules

silicon

weaker then carbon, no double bonds, no mobility

carbohydrates

source of energy, cellular structures

lipids

store energy for cells, major components of membranes

proteins

work-horses of cells, built from chains of amino acids

nucleic acids

DNA and RNA

metabolism

many chemical reactions that occur in living organisms

source of carbon

build chemical products

source of energy

fuel metabolic processes

heterotrophs

obtain carbon by eating

autotrophs

obtain carbon from environment

gene

DNA sequence for a single protein

genome

an organisms complete set of genes

mutation

agent of evolution and change of molecular machinery

stromatolites

structurally/chemically similar to “living stromatolites”, implication of photosynthesis

microfossils

more challenging to confirm biological origin

where

shallow ponds (Darwin) and deep-sea volcanic vents or underground

miller-urey experiment

demonstration that organic building blocks can form easily and naturally

RNA world

RNA is simpler than DNA, hold hereditary information, catalyze chemical reactions, first hereditary molecule of life

artificial life

life created in the lab, solves climate issues and biological weapons

first requirement

building blocks of life

second requirement

sunlight energy

third requirement

liquid water

advantages of water

broad/high tempature range, ice floats, charger separation facilitates biochemistry

moon/mercury

water ice likely, no liquid water, life highly unlikely

venus

extreme temperature surface and pressure, life extremely unlikely, clouds may offer safe harbors if life evolved

jupiter/saturn

liquid water underground, no life

uranus/neptune

liquid water near core, “ocean”, unlikely to be testable for life, probably no life

flyby

cost-effective, can pass multiple worlds but only quick look at each

orbiter

needs more fuel, tons on mars

landers/rovers/probes

lands on planet, several on mars

sample return

most expensive, small things

moven

orbits around mars, studies atmosphere of mars

mars

liquid water below ground, maybe life, no liquid water on surface pressure is too low, little internal heat, more extreme seasons, polar caps

mars vs earth

size is 50% radius of earth, mass is 10% of earth, surface gravity is 40% less than earths, pressure is much less than earth

mars atmosphere

mostly CO2 (95%), N2 (3%)

earth atmosphere

mostly N2 (77%), CO2 (.04%)

mars surface temperature

50 degrees celsius, freeze or evaporate, no liquid water on surface

earth surface temperature

+15 degrees celsius, plenty of liquid water on surface in the past

3 things of life on earth (geo)

volcanism (atmosphere/oceans), plate tectonics (climates stability), and magnetic field (no solar wind stripping)

internal heat

turkey vs chicken nugget, nugget cools down faster due to its size and mass

affects of internal heat

lava stays liquid without heat (volcanism), has molten core/stuff cannot move (plate tectonics), and no convecting molten (magnetic field)

more extreme seasons

larger TILT (25 degrees vs 23.5), more elliptical orbit

polar caps

permanent is water ice (H2O), seasonal is dry ice (CO2)