Question 1

Three stages of origin of life

Accepted Answer

1. formation of small organic molecules
2. Formation of self-replicating molecules
3. Development of cell membranes

Question 2

formation of small organic molecules

Accepted Answer

-amino acids
-nucleotides 
Stanley Miller (shown) and Harold Urey developed a simple
four-step experiment that demonstrated how complex organic
molecules could have arisen in earth’s early environment.

Question 3

Urey Miller experiment

Accepted Answer

1.create a fake earth and atmosphere. add heat
2. atmosphere rises. add electric shock (lightning)
3. condensations of atmosphere contents. cooling 
-discovered many organic molecules

Question 4

formation of self replicating molecules

Accepted Answer

-RNA: able to act as an enzyme. easier to replicate than DNA
-Molecule variation and self-replicating molecules lead to natural selection
-Almost living, but cannot carry out metabolism on their own

Question 5

the first genes

Accepted Answer

1. RNA monomers 
2. Formation of short RNA polymers 
3. Assembly of complementary RNA chain (pair up)
4. Complementary chain serves as template for making a copy of the original gene

Question 6

development of cell membranes

Accepted Answer

-necessary for metabolism :
-Passive and active transport
-Electron transport chain
-Self replication molecules + metabolic chemicals + all wrapped up together in a membrane = life

Question 7

alternative hypothesis (1st)

Accepted Answer

"cold soup":
-The three stages occurred during a period when earth was a giant snowball
-Unique characteristics of freezing water and ice may have contributed

Question 8

alternative hypothesis (2nd)

Accepted Answer

Extraterrestrial hypothesis:
-Early organic molecules brought to earth by meteors 
-Certain amino acids have been found in meteorites

Question 9

biological species

Accepted Answer

1. Populations of organisms that interbreed with each other
2. Or could possibly breed under natural conditions
3. And are reproductively isolated from such other groups

Question 10

bio species don't always work (1-3)

Accepted Answer

1. asexual species: no interbreeding=no reproductive isolation
2. Classifying fossil species: cannot reveal whether there was reproductive isolation 
3. Determining when one species has changes into another

Question 11

bio species don't always work (4-5)

Accepted Answer

4. Classifying ring species: there is no exact point where one species stops and the other begins.
5. Classifying hybridizing species: Hybridization—the interbreeding of closely related species—sometimes occurs and produces fertile offspring

Question 12

reproductive barriers for closely related species

Accepted Answer

1. prezygotic (no mating)
2. postzygotic (mating, but no offspring or infertile offspring)

Question 13

prezygotic barriers

Accepted Answer

-behavioral barriers: different mating calls
-temporal barriers: mating in different seasons
-habitat barriers: never meet to mate

Question 14

postzygotic barriers

Accepted Answer

-hybrid offspring viability: Offspring are produced but do not live long enough to reproduce
-Hybrid offspring sterility: species do produce offspring, but they are often sterile

Question 15

speciation

Accepted Answer

-when one species split into two distinct species

Question 16

two parts to speciation

Accepted Answer

1. reproductive isolation: some portion of a population can no longer reproduce with another portion 
2. Genetic divergence: -once the isolation occurs, mutations will accrue separately for each portion

Question 17

allopatric separation

Accepted Answer

-Occurs when a geographic barrier causes one group of individuals in a population to be reproductively isolated from another group

Question 18

sympatric separation

Accepted Answer

-populations diverge due to being genetically separated
-most common in plants 
1. chromosome duplication 
2. Combining chromosomes from two different species:

Question 19

how we organize life

Accepted Answer

Linnaean taxonomic hierarchy
Order from least to greatest: (species, genus, family, order, class, phylum, kingdom, domain)

Question 20

domain

Accepted Answer

bacteria, archaea, eukarya

Question 21

after life evolved

Accepted Answer

1. Bacteria the first self-replicating cells
2. There was a split between the bacteria and a line that gave rise to the archaea and eukarya
3. The fusion of bacterium and archaeon-like prokaryote created eukarya, which split from the archaea line

Question 22

bacteria

Accepted Answer

-All bacteria share a common ancestor and have a few features in common
-All are prokaryotic, asexual, single-celled prokaryote, no nucleus, organelles
-one+ circular molecules of DNA
-Have several methods of exchanging genetic information separately

Question 23

archaea

Accepted Answer

-split from Eukarya more recently than their split from bacteria.
-single celled prokaryote
-Cell walls contain polysaccharides not found in bacteria or eukaryotes.
-love to live in extreme environments

Question 24

Archaea are divided into five groups based on physiological features:

Accepted Answer

1. Thermophiles – “heat lovers”
2. Halophiles – “salt lovers”
3. High-and low-pH tolerant archaea
4. High-pressure tolerant archaea
5. Methanogens – methane-producing anaerobes (NOT oxygen-using)

Question 25

eukarya

Accepted Answer

Consists of the four kingdoms: plants, animals, fungi, and protists
-Most named species are eukaryotes.
-Most eukaryotes are multicellular

Question	Answer
Three stages of origin of life	1. formation of small organic molecules 2. Formation of self-replicating molecules 3. Development of cell membranes
formation of small organic molecules	-amino acids -nucleotides Stanley Miller (shown) and Harold Urey developed a simple four-step experiment that demonstrated how complex organic molecules could have arisen in earth’s early environment.
Urey Miller experiment	1.create a fake earth and atmosphere. add heat 2. atmosphere rises. add electric shock (lightning) 3. condensations of atmosphere contents. cooling -discovered many organic molecules
formation of self replicating molecules	-RNA: able to act as an enzyme. easier to replicate than DNA -Molecule variation and self-replicating molecules lead to natural selection -Almost living, but cannot carry out metabolism on their own
the first genes	1. RNA monomers 2. Formation of short RNA polymers 3. Assembly of complementary RNA chain (pair up) 4. Complementary chain serves as template for making a copy of the original gene
development of cell membranes	-necessary for metabolism : -Passive and active transport -Electron transport chain -Self replication molecules + metabolic chemicals + all wrapped up together in a membrane = life
alternative hypothesis (1st)	"cold soup": -The three stages occurred during a period when earth was a giant snowball -Unique characteristics of freezing water and ice may have contributed
alternative hypothesis (2nd)	Extraterrestrial hypothesis: -Early organic molecules brought to earth by meteors -Certain amino acids have been found in meteorites
biological species	1. Populations of organisms that interbreed with each other 2. Or could possibly breed under natural conditions 3. And are reproductively isolated from such other groups
bio species don't always work (1-3)	1. asexual species: no interbreeding=no reproductive isolation 2. Classifying fossil species: cannot reveal whether there was reproductive isolation 3. Determining when one species has changes into another
bio species don't always work (4-5)	4. Classifying ring species: there is no exact point where one species stops and the other begins. 5. Classifying hybridizing species: Hybridization—the interbreeding of closely related species—sometimes occurs and produces fertile offspring
reproductive barriers for closely related species	1. prezygotic (no mating) 2. postzygotic (mating, but no offspring or infertile offspring)
prezygotic barriers	-behavioral barriers: different mating calls -temporal barriers: mating in different seasons -habitat barriers: never meet to mate
postzygotic barriers	-hybrid offspring viability: Offspring are produced but do not live long enough to reproduce -Hybrid offspring sterility: species do produce offspring, but they are often sterile
speciation	-when one species split into two distinct species
two parts to speciation	1. reproductive isolation: some portion of a population can no longer reproduce with another portion 2. Genetic divergence: -once the isolation occurs, mutations will accrue separately for each portion
allopatric separation	-Occurs when a geographic barrier causes one group of individuals in a population to be reproductively isolated from another group
sympatric separation	-populations diverge due to being genetically separated -most common in plants 1. chromosome duplication 2. Combining chromosomes from two different species:
how we organize life	Linnaean taxonomic hierarchy Order from least to greatest: (species, genus, family, order, class, phylum, kingdom, domain)
domain	bacteria, archaea, eukarya
after life evolved	1. Bacteria the first self-replicating cells 2. There was a split between the bacteria and a line that gave rise to the archaea and eukarya 3. The fusion of bacterium and archaeon-like prokaryote created eukarya, which split from the archaea line
bacteria	-All bacteria share a common ancestor and have a few features in common -All are prokaryotic, asexual, single-celled prokaryote, no nucleus, organelles -one+ circular molecules of DNA -Have several methods of exchanging genetic information separately
archaea	-split from Eukarya more recently than their split from bacteria. -single celled prokaryote -Cell walls contain polysaccharides not found in bacteria or eukaryotes. -love to live in extreme environments
Archaea are divided into five groups based on physiological features:	1. Thermophiles – “heat lovers” 2. Halophiles – “salt lovers” 3. High-and low-pH tolerant archaea 4. High-pressure tolerant archaea 5. Methanogens – methane-producing anaerobes (NOT oxygen-using)
eukarya	Consists of the four kingdoms: plants, animals, fungi, and protists -Most named species are eukaryotes. -Most eukaryotes are multicellular

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Bio chp 12