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46 Cards in this Set
- Front
- Back
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What is conjugation? |
Transfer of DNA from one bacterium to another (horizontal transmission) |
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What is the Great Plate Count Anomaly? |
That some microorganisms cannot be cultured in the lab. |
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What translates DNA into protein? |
RNA |
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What is taxonomy? |
Classifying life forms by comparing their shapes. |
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What is another word describing bacteria and archaea |
Prokaryotes |
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What are the three domains of life? |
Bacteria, archarea, and eukaryota |
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Define phylogenetics |
Study of relationships between groups of organisms |
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What carbon isotope is preferred by life? |
C^12 |
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Who proposed the nebular hypothesis and when? |
Immanuel Kant, 1755 |
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What do the appearance of limestone, carbonite, sandstone, and pillow lava suggest about early Earth? |
There was liquid water |
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How old are the oldest rocks formed, and what percentage of Earth history is missing? |
4 - 3.8B years old ~11% missing |
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What is the period of frequent meteorite and asteroid strikes called? |
Late Heavy Bombardment |
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As the Sun was 25% less luminous during early Earth, what kept the planet from freezing? |
Greenhouse effect from CO^2 and methane |
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When did Earth form? |
4.56B yrs ago
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What is molecular cloud? |
A region of space where H, He, and heavier element combine to form structures |
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What is the nebular hypothesis? |
The idea that structures in molecular clouds collapse to form protostar |
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What composed early Earth's atmosphere? |
CO^2, methane, and trace amounts of O^2 |
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What reaction makes protostars give off heat and light? |
Nuclear fusion |
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What kinds of planets are formed on either side of the ice line? |
Gas giants form beyond ice line, rocky planets form inside ice line. |
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What is the earliest known life? |
Stromatolights |
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According to fossils and chemical signatures in the geological record, when was life established on early Earth? |
3.5-3B yrs ago |
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Name a characteristic of extreme environments. |
Diversity of life decreases |
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What are extremophiles? |
Creatures that live in extreme environments. Mostly prokaryotes, but there are some eukaryotes |
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Name 8 kinds of extreme environments |
-hot -cold -salty -dry -high pressure -high radiation -acidic -basic |
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Give example of a hot environment on Earth |
Deep sea hydrothermal vent |
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What types of creatures live in hot environments, and at what temperatures? |
-thermophile (50-80 C) -hyperthermophiles (80+ C) |
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Name two common challenges for thermophiles. |
-breakdown of bio molecules -maintaining cell membrane fluidity |
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Name one adaptation of thermophiles. |
-extra chemical bonds promote thermostable proteins and enzymes |
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What type of creature lives in cold environments and at what temperature? |
-psychophiles (15 C) |
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Name some challenges faced by psychophiles. |
-damage to cell membrane -lack of membrane fuidity -lipids begin to solidify and cell cannot import/export material -no liquid water |
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Name two adaptations made by psychophiles. |
-incorporation of more unsaturated fatty acids -use of antifreeze agents, eg. sugar |
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What creatures live in salty environments and at what concentrations? |
-halophiles (15-37% conc.) |
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What creatures live in very dry environments? |
-xerophiles |
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Name some challenges of salty and dry environments. |
-osmotic pressure -water availability -salt pulling water out of cells -maintaining membrane integrity |
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What are some adaptations made by creatures living in salty or dry environments? |
-produce salts and solutes to hold in water -go dormant until conditions improve |
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What creatures live in highl acidic or basic environments? |
-acidophiles and alkaliphiles |
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What are some challenges of living in very acidic or basic environments? |
-dissolution of cell membrane -affected metabolism |
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Name an adaptation performed by acidophiles or alkaliphiles. |
-maintenance of cellular pH |
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What creatures live in high-pressure environments? |
-prezophiles |
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What is the upper limit of pressure for life? |
Unknown |
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What are some challenges of high-pressure environments? |
-tight-packed cells -loss of fluidity -impaired cellular function |
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What are some adaptations made by prezophiles? |
-change gene expression to improve nutrient absorption -change membrane structure to take on more unsaturated fatty acids, increasing cell fluidity |
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What is the most extreme known environment and why? |
-outer space -high radiation, freezing temperatures, dessication, no oxygen |
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Name a microbe that has survived in the vacuum of outer space. |
Gleocapsa |
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What kind of creatures live in environments of more than one extreme? |
Polyextremophiles |
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Name two reasons to study extreme environments. |
-tells boundaries of Earth's biosphere -gives ideas about habitibility of other worlds |
