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Intelligent life in the universe > exam 2 > Flashcards

exam 2 Flashcards

1
Q

Define an extremophile

A

An organism that can thrive in extreme environments, like space (like tardigrades), high heat (thermophiles), high pressure (barophiles), etc.

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2
Q

Know the different categories of extremophiles covered in class

A
  • halophiles thrive in extremely salty environments
  • Lichen thrive in high radiation (not the technical name for them?)
  • Aerobes thrive in oxygen (humans)
  • Thermophiles thrive in high temps
  • Psychrophiles thrive in low temps
  • Acidophiles thrive in extremely acidic environments
  • Alkaliphiles thrive in extremely basic environments
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3
Q

Be able to interpret growth curves for different environmental parameters

A

lower limit, its optimum where it grows best, and a upper limit (salinity chart on Halophiles)

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4
Q

What would liquid water on Mars be like?

A

Temp below freezing but would remain liquid due to the fact that it’s saturated with salt

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5
Q

What evidence is there of flowing water on Mars?

A

The picture showing the streak pattern on the surface that indicates flowing water

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6
Q

Can life as we know it survive on Mars?

A

No. It’s too cold and has lower pressure.

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7
Q

With regards to temperature both hot and cold, what prevents a cell from growing?

A
  • Hot temperatures cause the cell membrane to break apart

- Cold temperatures, membrane becomes less fluid so things can’t get through it. Cell stops functioning

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8
Q

From an extremophile perspective what is unique about Mono Lake, Rio Tinto, The Via Luz cave, The Dead Sea?

A

Only halophiles live in extremely salty environments such as these.

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9
Q

Which domain is generally the best at surviving in extreme environments? The worst?

A

archaea is best at surviving them, eukarya is worst

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10
Q

Be able to describe the basic structure of DNA.

A
  • The two strands of the “backbone” are wound in the shape of double helix
  • Two strands are connected with four bases (T, A, C, G)
  • T only attaches to A
  • C only attaches to G
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11
Q

Who discovered the structure of DNA.

A
  • Rosalind Franklin

- Didn’t get credit, but Watson and Crick did

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12
Q

What is lateral gene transfer?

A
  • cells give genes to cells

- exchange to genes within us

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13
Q

How do microbes impact our bodies?

A
  • Gut bacteria tell their hosts what to eat in order to help it advance
  • The microbiome may yield a new class of psychobiotics for treatment of anxiety, depression, and other mood disorders
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14
Q

What is the Cambrian explosion?

A

-happened about 0.5 GYA during the Cambrian period, major groups of animals first appeared on fossil records at this time.

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15
Q

What are the characteristics of LUCA?

A

-thermophile, lives in the water, autotroph

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16
Q

Know about the Chernobyl fungi, Deionococcus, and the Mantis Shrimp.

A
  • Mantis Shrimp- vision extends from ultraviolet to far red (almost infrared); Has 16 vision receptors; Powerful claws are capable of extreme acceleration, comparable to a rifle bullet.
  • Chernobyl fungi- actually eats radiation, rich in melanin
  • Deionococcus- bacteria that is particularly good at surviving in radiation and good at putting its genome back together. Leading bacteria for growing in radiation. Can actively grow at thousands of rays of radiation
17
Q

What is oxygenic/anoxygenic photosynthesis? When did each arise?

A

Anoxygenic- H2S instead of H20 (no oxygen). About 3.5 GYA

Oxygenic- H20 (uses oxygen). About 2.5 GYA

18
Q

When did our atmosphere become oxygenated? What are the implications of this?

A

-2.7 billion years ago, cyanobacteria invented oxygenic photosynthesis. This killed off a lot of life that can’t handle much oxygen.

19
Q

What are Banded Iron Formations?

A
  • ’rusty’ bands in the rock layers dating back 2.7 billion years ago
  • once life evolved oxygenic photosynthesis, it’s releasing oxygen into the atmosphere that reacts with the unoxidized iron in the ocean to create rust
20
Q

What is a dropstone and what does it indicate?

A

-The stone that was moved by the glacier, indicating that that tropical region was in an ice age at some point

21
Q

On a million year timescale, how is Earth’s thermostat set. Be able to discuss in detail.

A
  • The amount of CO2 in the atmosphere
  • Atmospheric carbon dioxide performs a role similar to that of the house thermostat in setting the equilibrium temperature of the Earth
  • Stable cycle of weathering, atmospheric CO2, greenhouse effect, and surface temp
22
Q

In terms of mineral evolution what factors contribute to increased mineral complexity on a celestial body?

A

water and life

23
Q

How does Daisy World fit in with the Gaia hypothesis?

A
  • The only things living on the planet are black daisies and white daisies. White daisies like hotter temps/lower albedo (how much light they absorb), black daisies like colder temps/higher albedo. As the planet warms, white daisies thrive. But since they absorb less sunlight, the temp cools, which causes black daisies to grow, which absorbs more sunlight and the temp increases causing more white daisies to grow.
  • Temp goes up without any daisies. With daisies, temp remains stable (feedback loop).

Gaia Hypothesis: - Says earth along with its biosphere was a self-regulating entity

  • Earth evolves and created its own temp
  • Fun interested thought experiment
24
Q

What causes mass extinction events?

A
  • Asteroid/ meteorite impact
  • Biological product like oxygen
  • Climate change cause by:
    o Humans (nuclear winter/ greenhouse gases)
    o Meteorite
    o Volcanic emissions
    o Earth ice age cycle
  • Disease
  • Humans mass killing
25
Q

What is the late heavy bombardment and what are its implications?

A

-during the late heavy bombardment (4.1-3.8 billion years ago), Earth was pummeled by asteroids, which probably would have killed all surface life.

26
Q

What were the characteristics of the Early Earth?

A
  • no oxygen/no ozone layer
  • less atmosphere pressure
  • dangerous levels of radiation from the sun
  • more volcanoes, emitting noxious gases
  • stronger tides because the moon was closer
  • days were shorter because Earth was spinning faster
27
Q

Compare and contrast the rocky planets.

A

Venus: hottest planet, similar mass to Earth, thick atmosphere, clouds of sulfuric acid
Mars: smaller than Earth, very thin atmosphere, most geologically inactive, frozen poles
Mercury: smallest planet, no atmosphere, closest to the sun, hot, most geologically inactive

28
Q

How did volcanoes help shape the atmospheres of Mars, Earth, and Venus?

A

-volcanoes add large quantities of gases to atmospheres (water vapor, carbon dioxide, many noxious gases)

29
Q

How did the early environments of Mars, Earth and Venus compare?

A
  • The early environments were similar.
  • Molten, hot core; volcanoes ‘belching’ out thick clouds of gas;
  • incoming comets crashing and depositing water;
  • surface warmed from both sunlight
  • early greenhouse effect producing moderate temperatures;
  • large oceans and plenty of water.
30
Q

How did Venus lose its atmosphere? How do we know?

A
  • 5832 hours is one day because its closer to the sun
  • slower rotation= A weaker magnetic felid
  • Because the magnetic field (protector) went away
  • For magnetic field you need BOTH fast rotation and liquid metal core
  • Solar wind bombards atmosphere and breaks up water vapor
  • Vast majority of hydrogen in space is one proton, no neutrons
  • This hydrogen is lighter
  • Hydrogen deuterium (one proton, one neutron) is heavier
  • Hydrogen left (blown away by solar winds) and left behind hydrogen deuterium
  • This proves that water left Venus because of solar winds
31
Q

What caused the planets to go from their early habitability to their current conditions?

A
  • Venus’s atmosphere went “up” into space
  • Mars’s atmosphere went up and down
  • Faint Young Sun Paradox: the sun got brighter (instead of cooler) and made planets like Venus lose their water faster
32
Q

What would happen if Earth moved closer to the sun?

A

The surface would heat up, causing the water to evaporate and increase the greenhouse effect resulting in a runaway greenhouse effect because the water would not come back down and contribute to the increasing effect.

33
Q

Understand the difference between a positive feedback loop and a negative feedback loop.

A

-Positive feedback doesn’t mean it’s good - it means that the feedback loop is causing an increase in something that causes the increase in something else, and it just keeps going.
A negative feedback is the same, but opposite. A decrease in something causes a decrease in something else, and it keeps going.

34
Q

How and why do the temperatures of planet interiors change over time?

A
  • Planets can lose their magnetic fields which cause the molten rock in the interior slow down or even decrease
  • They cool slowly like a potato and smaller planets cool faster like French fries
35
Q

What is the most important characteristic (heat, salinity, PH, etc?) in determining what can live where?

A

A moderate temperature (heat)

36
Q

Know the basic timeline of life on Earth covered in class.

A
  • 4 billion years ago (4.1- 3.8 billion years) we have late heavy bombardment of meteorites
  • Origin of life 3.8 billion years ago
37
Q

What is the Gaia hypothesis? What is the contribution of Lynn Margolis to science?

A
  • She developed the symbiotic theory, which states that bacteria played a major role in the development of living cells
  • Hypothesis that the earth and all living beings on earth that is self-regulated system

Intelligent life in the universe (3 decks)

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