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BIOL 322 > Topic 1: Evolution of life on earth > Flashcards

Topic 1: Evolution of life on earth Flashcards

1
Q

what is abiogenesis

A

theory that life originated from inorganic/non-living substances

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2
Q

what is biogenesis

A

origin of life from organic, pre existing matter

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3
Q

approximately when did Earth form, what were the conditions

A

about 4.6 BYA
sterile and inhospitable

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4
Q

when was the hadean eon and what were the characteristics of it

A

4-4.6 BYA
- meteor bombardments, and water was present in form of vapor
- low biosignature

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5
Q

when was the Archaean eon and what were the characteristics of it

A

2.5-4 BYA
- stable oceans began forming, cyanobacteria and prokaryotes present
- anoxygenic photosynthesis

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6
Q

approximately when did microbial life appear on Earth

A

3.8 BYA
- evidence of some biosignature present

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7
Q

what are stromatolites

A

fossil evidence
- cyanobacteria on limestone, photosynthesize and create by product of oxygen

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8
Q

what are the microbial layers of stromatolites

A

green layer- diatoms/cyanobacteria
pink layer - purple sulfur bacteria
crystalline layer - sulfate reducing bacteria
black layer

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9
Q

what are the carbonate layers of stromatolites

A

top 1- primary layer
top 2- porous layer
top 3- compact layer
top 4- bottom layer

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10
Q

what are examples of microfossils

A
  • clonial cyanpbacteria
  • filamentous prokaryotes
    -algae
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11
Q

what are examples of chemical biosignature

A

kerogen-> substances produced by the decay of living organism
- membrane lipids

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12
Q

what is the great oxidation event
when was it

A

2.1- 3 BYA

followed by the proliferation of cyanobacteria–> producing high by-products of oxygen which lead to highly oxic environments.
- microbes evolved to adapt to oxic environment

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13
Q

what is panspermia theory

A

theory that life was transported to earth following meteorites, asteroids, or comets.

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14
Q

what is spontaneous generation model and who proposed it

A

hypothetical process by which living organisms develop from non living matter
(aristotle)

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15
Q

what is the primordial/prebiotic soup model

A

oparin and haldane hypothesis
- primitive water bodies were full of inorganic material, the atmosphere was methane/ammonia dominated
- strong impact by lightening or UV caused formation of life

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16
Q

what is the Urey Miller experiment

A

replicated environment with methane, ammonia, water, and hydrogen
- used 50,000-60,000 voltage to replicate lightening
- resulted in 15-13 or 22 amino acids

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17
Q

what was the significance of the miller urey experiment

A

Inorganic materials can form organic molecules in the right conditions
- insight on prebiotic chemistry

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18
Q

describe differences between DNA and RNA

A

DNA– double stranded, no OH group
RNA- single stranded– OH group on ribose

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19
Q

what are the 3 key qualities of RNA that contribute to RNA world hypothesis

A
  • capable of storing genetic info
  • can catalyze chemical reactions
  • recent studies show RNA can self replicate
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20
Q

what are limitations of RNA world hypothesis

A

RNA is more unstable than DNA

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21
Q

what are the strong and weak points on the theories that proteins came to form life first

A
  • amino acids are synthesized under a variety of conditions
  • can exhibit catalytic activity
  • amino acids compose high diversity of information content

weak:
- lack of self replication
- proteins require DNA for function

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22
Q

what is the central dogma

A

flow of genetic info from DNA to RNA to make functional protein
- DNA replication
- Transcription (DNA-RNA)
- translation (RNA-protein)

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23
Q

what is the role of ribosomes in the central dogma

A

factories that translate code of DNA into functional unit (protein)

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24
Q

define gene expression

A

process by which DNA is converted into a functional product

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25
what is the role of mRNA
relaying message in DNA to protein translation apparatus
26
what is a ribozyme
catalytic RNA molecules, break and form covalent bonds in RNA
27
what is evidence of endosymbiosis (MADDR)
M- membranes (evidence of double membrane) A- antibiotics (susceptibility to antibiotics) D- Division (reproduction through binary fission D- DNA (mitochondria/chloroplast has own DNA) R- ribosomes (have its own ribosomes)
28
differentiate between eukaryotic cell and prokaryotic cells
eukaryotic: membrane bound nucleus with organelles prokaryotic: unicellular lacking nucleus and organelles
29
what is LUCA
last universal common ancestor - assumed single celled
30
what is a clade/monophyletic group
consists ancestral species and all its descendants
31
what is a paraphyletic group
consists of common ancestor but some (not all) its descendants
32
what is a polyphyletic group
species grouped by similarity, not from common ancestor
33
what is the difference between a cladogram and phylogram
cladogram- branches are uniform in length and are not proportional to the length of time of evolution phylogram- different branch lengths that are proportional to the length of time of evolution
34
what is an outgroup
taxon that diverges from the tree prior to the last common ancestor of the taxa being studied
35
what is homology
sharing of traits via common ancestry
36
what is analogy
similar traits but independent origins
37
what is divergent evolution
group from same common ancestor evolve and accumulate differences
38
what is convergent evolution
organisms sharing analogous traits that are not inherited from a common ancestor
39
what is parallel evolution
independent evolution of similar traits from similar ancestral conditions
40
what are derived traits
traits that are not present in the common ancestor of all species of interest
41
what are ancestral traits
traits present in common ancestor of all species
42
what is evolution
the change of alleles frequencies in a set of organisms over time
43
what is microevolution
evolutionary changes that occur over relatively short periods of time within a population
44
what is macroevolution
evolution that results in relatively large changes over a long period of time
45
what processes give rise to new alleles
mutations and recombination
46
what causes changes in allele frequency
selection and genetic drift
47
define mutation
random changes in DNA sequence that accumulate in all DNA sequences over time
48
what is recombination
segments of DNA are broken and rejoined to create new combination of genetic material
49
what are environmental factors that influence mutations
sunlight xrays and radiation tobacco chemicals nitrites
50
what is single nucleotide polymorphism
changes a single nucleotide in a DNA sequence (point mutation)
51
what are indel mutations
insertion or deletion mutations that result in addition or removal of one or more nucleotides result in frameshift mutations (shift in reading frame of DNA template)
52
what is transition mutation
changes from purines to purines (AG) or pyrimidines to pyrimidines (CT)
53
what is transversion mutation
changes from purines (AG) to pyrimidines (TC) or vice versa
54
what is the frequency of error in a single round of replication
10^-6 to 10^7 per thousand bases
55
what is the most frequent to least frequently occurring mutation
missense> silent> nonsense
56
what is duplication mutation
a piece of DNA that has been copied more than one time
57
what is horizontal gene transfer
uptaking foreign DNA that is not in the organisms direct cellular lineage
58
what is transformation
competence-- the uptake of free naked DNA from the environment can be natural or artificial (requires calcium or lightening)
59
what is general transduction
allows for transfer of any gene through phage infection (taking DNA from phage cells)
60
what is specialized transduction
allows for transfer of selective genes and small region of a chromosome (also with phages)
61
what is the Pasteur experiment
disproved spontaneous generation showed that a boiled nutrient broth did not give rise spontaneously to new life, but that if direct access to air was permitted, the broth decomposed, implying that small organisms (in modern terms, microbial spores) had fallen in and started to grow in the broth.

BIOL 322 (3 decks)

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