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38 Cards in this Set

  • Front
  • Back
What is the range of dates for the origin of life?
3.5 to 4.0 billion years ago
Where were the oldest fossils found?
western Australia
What type of life dominated between 3.5 and 2.0 billion years ago?
In what form are most early prokaryote fossils found?
in stromatolites, mats of fossilized microbes
When did cyanobacteria evolve?
>2.7 billion years ago
Where did the first oxygen go?
It dissolved into the ocean and seas until it became saturated, and also oxidized iron in the water to iron oxides.
Besides stromatolites, where else have early fossils been found?
near hydrothermal vents
When did atmospheric oxygen concentrations increase the most?
around 2.2 billion years ago
What caused the second increase in O2 in the atmosphere?
the development of eukaryotes with chloroplasts
When did eukaryotes first appear?
between 2.1 and 2.7 billion years ago
What are endosymbionts?
symbiotic cells w/in the larger host cell, like mitochondria and chloroplasts
When did multicellular eukaryotes arise?
molecular clocks say 1.5 billion years ago, but the earliest found are 1.2
When is the snowball earth hypothesized to have been?
750-570 million years ago
When did the major animal phyla appear?
~543 million years ago
What two animal phyla evolved first?
cnidarians (jellies) and poriferans (sponges)
When was the land colonized?
around 500 million years ago
Which two groups landed first?
plants and fungi (near their roots)
Order these: mammals, fishes, birds, reptiles, amphibians.
fishes -> amphibians -> reptiles -> birds and mammals
Pasteur's principle of life from life is called what?
What are the four stages of the origin of life?
1) small organic molecules, 2) polymerization, 3) self-replication, 4) packaging into protobionts w/membranes
Why can't life arise today?
Oxygen in the atmosphere prevents macromolecules from forming.
Who first hypothesized the origin of life scenario?
Oparin and Haldane
What gases were in the Miller-Urey flask?
water, hydrogen, methane, ammonia
What differences are there between the Miller-Urey atmosphere and the early atmosphere hypothesized today?
carbon monoxide, carbon dioxide, nitrogen, and some oxygen also there, no hydrogen left
Other than the sea-atmosphere boundary, where have small organic molecules been hypothesized to arise?
deep-sea hydrothermal vents and outer space
Where were polymers first formed?
hot rocks would have vaporized the water, concentrated the monomers, and caused them to polymerize
What was likely the first genetic material?
Which came first, genes or enzymes?
RNA served as both.
What are ribozymes and what do they do?
RNA catalysts that remove introns from RNA and catalyze RNA (r, t, m) synthesis
How would natural selection work in an RNA world?
RNA molecules would compete for monomers, and those that are more stable would outcompete others and grow.
What are protobionts?
aggregates of abiotically produced molecules that maintain a different chemical environment inside than outside and metabolize for energy
What are similar to protobionts?
Liposomes, when lipids form a bilayer like cell membranes
Why did DNA take over for RNA?
DNA is much more stable than RNA.
Who invented the five-kingdom system when?
Robert Whittaker of Cornell in 1969
What are the five kingdoms?
Monera, Protista, Plantae, Fungi and Animalia
How did Whittaker define the kingdoms?
Plants are photosynthetic autotrophs, fungi are absorptive heterotrophs, animals are digestive heterotrophs, protists are all other eukaryotes and Monera are prokaryotes.
What are the three domains?
Bacteria, Archaea, and Eukarya
How do the five kingdoms and three domains fit into each other?
Bacteria and Archaea are within Monera, while Eukarya consists of the other four kingdoms.