exam 2 Flashcards
(37 cards)
Define an extremophile
An organism that can thrive in extreme environments, like space (like tardigrades), high heat (thermophiles), high pressure (barophiles), etc.
Know the different categories of extremophiles covered in class
- 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
Be able to interpret growth curves for different environmental parameters
lower limit, its optimum where it grows best, and a upper limit (salinity chart on Halophiles)
What would liquid water on Mars be like?
Temp below freezing but would remain liquid due to the fact that it’s saturated with salt
What evidence is there of flowing water on Mars?
The picture showing the streak pattern on the surface that indicates flowing water
Can life as we know it survive on Mars?
No. It’s too cold and has lower pressure.
With regards to temperature both hot and cold, what prevents a cell from growing?
- 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
From an extremophile perspective what is unique about Mono Lake, Rio Tinto, The Via Luz cave, The Dead Sea?
Only halophiles live in extremely salty environments such as these.
Which domain is generally the best at surviving in extreme environments? The worst?
archaea is best at surviving them, eukarya is worst
Be able to describe the basic structure of DNA.
- 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
Who discovered the structure of DNA.
- Rosalind Franklin
- Didn’t get credit, but Watson and Crick did
What is lateral gene transfer?
- cells give genes to cells
- exchange to genes within us
How do microbes impact our bodies?
- 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
What is the Cambrian explosion?
-happened about 0.5 GYA during the Cambrian period, major groups of animals first appeared on fossil records at this time.
What are the characteristics of LUCA?
-thermophile, lives in the water, autotroph
Know about the Chernobyl fungi, Deionococcus, and the Mantis Shrimp.
- 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
What is oxygenic/anoxygenic photosynthesis? When did each arise?
Anoxygenic- H2S instead of H20 (no oxygen). About 3.5 GYA
Oxygenic- H20 (uses oxygen). About 2.5 GYA
When did our atmosphere become oxygenated? What are the implications of this?
-2.7 billion years ago, cyanobacteria invented oxygenic photosynthesis. This killed off a lot of life that can’t handle much oxygen.
What are Banded Iron Formations?
- ’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
What is a dropstone and what does it indicate?
-The stone that was moved by the glacier, indicating that that tropical region was in an ice age at some point
On a million year timescale, how is Earth’s thermostat set. Be able to discuss in detail.
- 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
In terms of mineral evolution what factors contribute to increased mineral complexity on a celestial body?
water and life
How does Daisy World fit in with the Gaia hypothesis?
- 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
What causes mass extinction events?
- 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
