Chapter 18: Origin and History of Life Flashcards
all life on earth can be traced back to a single ancestor → …: …
LUCA: last universal common ancestor
LUCA common to all organisms that have
lived or live on Earth
According to Darwin, first life form came about in a … with …, …, .., …, …, etc
warm little pond; ammonia; phosphoric salts; light; heat; electricity
biomolecules: the molecules of … → …
living things; organic molecules
life originated from nonliving matter in
4 stages
(4 stages) stage 1: …., simple … evolved from … before cells came to be: e.g. .. and …
organic monomers; monomers; inorganic compounds; amino acids; nucleotides
(4 stages) stage 2: …, organic monomers … to form …: e.g. …, …, and …
organic polymers; polymerized; organic polymers; DNA; RNA; proteins
(4 stages) stage 3: …, organic polymers became …, forming the … (…/…)
protocells; enclosed in a membrane; cell precursors; protocells; probionts
(4 stages) stage 4: …, probionts acquired ability to …, among other …
living cells; self-replicate; cellular properties
abiogenesis: origin of … from ..
.life; nonliving matter
(stage 1. evolution of monomers) oparin-haldane hypothesis → … hypothesis
primordial soup
(stage 1. evolution of monomers) oparin-haldane: first stage in the origin of life was … from … present in Earth’s ….
evolution of monomers; inorganic compounds; early atmosphere
(stage 1. evolution of monomers) early earth had very little …, made up of …, …, …, …
oxygen; water vapor; hydrogen gas; methane; ammonia
(stage 1. evolution of monomers) methane and ammonia are …, powerful when ….
reducing agents; oxygen is absent
(stage 1. evolution of monomers) oparin-haldane: early earth had …. in which .. reactions could have driven … (…) of organic monomers from inorganic molecules with addition of …
reducing atmosphere (because of CH4 and NH3); redox; chemical evolution; abiotic synthesis; energy
(stage 1. evolution of monomers) miller-urey experiment: early earth energy sources: heat from … and …, … from isotopes, … in …, … (particularly …)
volcanoes; meteorites; radioactivity; electric discharges; lightning; solar radiation; ultraviolet
(stage 1. evolution of monomers) miller-urey experiment: miller placed mixture of …, …, …, and … in a closed system and … it, and also circulated it past an …
methane; ammonia; hydrogen; water; heated; electric spark
(stage 1. evolution of monomers) miller-urey experiment: variety of … and other … were formed
- all …
amino acids; organic acids; 22 amino acids
(stage 1. evolution of monomers) miller-urey experiment: recent evidence suggests that … and … would have been abundant in early Earth atmosphere, challenging validity of experiment
BUT: other experiments showed that ammonia could have been produced when ….
nitrogen gas; ammonia; iron-nickel sulfides catalyzed change of N2 to NH3
(stage 1. evolution of monomers) miller-urey experiment: small organic compounds formed on surface by atmospheric gases would not have been destroyed through … or …, as there was no … or …, and … would have washed them into the … where the … could become …
oxidation; decay; free oxygen; bacteria; ocean; oceans; warm organic soups
(stage 1. evolution of monomers) iron-sulfur world hypothesis: proposal that thermal vents at the bottom of oceans could have provided all the … and … necessary to …
elements; conditions; synthesize organic monomers
(stage 1. evolution of monomers) iron-sulfur world hypothesis: … emitted from vents (…., …, …) pass over … and … minerals, which would then act as … that drive chemical evolution from …. to … molecules
dissolved gases; carbon monoxide; ammonia; hydrogen sulfide; iron; nickel; catalysts; inorganic; organic molecules
(stage 1. evolution of monomers) extraterrestrial origins hypothesis: organic molecules from … and … could have .. the chemical origin of life on earth
comets; meteorites; seeded
(stage 1. evolution of monomers) extraterrestrial: some hypothesize that … evolved first on another planet
bacterium-like cells
(stage 2. evolution of polymers) in cytoplasm, organic monomers join to form … in the presence of …
polymers; enzymes
(stage 2. evolution of polymers) enzymes are
proteins
(stage 2. evolution of polymers) iron-sulfur world hypothesis: organic molecules will …. and amino acids will form … in presence of …. under conditions found at …
react; peptides; iron-nickel sulfides; thermal vents
(stage 2. evolution of polymers) iron-sulfur world hypothesis: iron-nickel sulfides have a … that attracts … and …. to form …
charged surface; amino acids; binds them together; proteins
(stage 2. evolution of polymers) protein-first hypothesis: amino acids polymerize abiotically when exposed to
dry heat
(stage 2. evolution of polymers) protein-first hypothesis: once amino acid were present in oceans, they could have collected in … along …
shallow puddles; rocky shore