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46 Cards in this Set

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What is conjugation?

Transfer of DNA from one bacterium to another (horizontal transmission)

What is the Great Plate Count Anomaly?

That some microorganisms cannot be cultured in the lab.

What translates DNA into protein?

RNA

What is taxonomy?

Classifying life forms by comparing their shapes.

What is another word describing bacteria and archaea

Prokaryotes

What are the three domains of life?

Bacteria, archarea, and eukaryota

Define phylogenetics

Study of relationships between groups of organisms

What carbon isotope is preferred by life?

C^12

Who proposed the nebular hypothesis and when?

Immanuel Kant, 1755

What do the appearance of limestone, carbonite, sandstone, and pillow lava suggest about early Earth?

There was liquid water

How old are the oldest rocks formed, and what percentage of Earth history is missing?

4 - 3.8B years old


~11% missing

What is the period of frequent meteorite and asteroid strikes called?

Late Heavy Bombardment

As the Sun was 25% less luminous during early Earth, what kept the planet from freezing?

Greenhouse effect from CO^2 and methane

When did Earth form?

4.56B yrs ago

What is molecular cloud?

A region of space where H, He, and heavier element combine to form structures

What is the nebular hypothesis?

The idea that structures in molecular clouds collapse to form protostar

What composed early Earth's atmosphere?

CO^2, methane, and trace amounts of O^2

What reaction makes protostars give off heat and light?

Nuclear fusion

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.

What is the earliest known life?

Stromatolights

According to fossils and chemical signatures in the geological record, when was life established on early Earth?

3.5-3B yrs ago

Name a characteristic of extreme environments.

Diversity of life decreases

What are extremophiles?

Creatures that live in extreme environments. Mostly prokaryotes, but there are some eukaryotes

Name 8 kinds of extreme environments

-hot


-cold


-salty


-dry


-high pressure


-high radiation


-acidic


-basic

Give example of a hot environment on Earth

Deep sea hydrothermal vent

What types of creatures live in hot environments, and at what temperatures?

-thermophile (50-80 C)


-hyperthermophiles (80+ C)

Name two common challenges for thermophiles.

-breakdown of bio molecules


-maintaining cell membrane fluidity

Name one adaptation of thermophiles.

-extra chemical bonds promote thermostable proteins and enzymes

What type of creature lives in cold environments and at what temperature?

-psychophiles (15 C)

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

Name two adaptations made by psychophiles.

-incorporation of more unsaturated fatty acids


-use of antifreeze agents, eg. sugar

What creatures live in salty environments and at what concentrations?

-halophiles (15-37% conc.)

What creatures live in very dry environments?

-xerophiles

Name some challenges of salty and dry environments.

-osmotic pressure


-water availability


-salt pulling water out of cells


-maintaining membrane integrity

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

What creatures live in highl acidic or basic environments?

-acidophiles and alkaliphiles

What are some challenges of living in very acidic or basic environments?

-dissolution of cell membrane


-affected metabolism

Name an adaptation performed by acidophiles or alkaliphiles.

-maintenance of cellular pH

What creatures live in high-pressure environments?

-prezophiles

What is the upper limit of pressure for life?

Unknown

What are some challenges of high-pressure environments?

-tight-packed cells


-loss of fluidity


-impaired cellular function

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

What is the most extreme known environment and why?

-outer space


-high radiation, freezing temperatures, dessication, no oxygen

Name a microbe that has survived in the vacuum of outer space.

Gleocapsa

What kind of creatures live in environments of more than one extreme?

Polyextremophiles

Name two reasons to study extreme environments.

-tells boundaries of Earth's biosphere


-gives ideas about habitibility of other worlds