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Bio Midterm 2 > The tree of life > Flashcards

The tree of life Flashcards

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Biology 101 flashcards
1
Q

What are the 7 properties of life?

A
  1. Cellular Organization
  2. Energy and Metabolism
  3. Reproduction
  4. Heredity + Evolution
  5. Growth + Development
  6. Homeostasis and regulation
  7. Response to stimuli
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2
Q

Why aren’t viruses considered living things?

A

They don’t have a cellular structure, they don’t metabolize internally, and they do not grow or develop.

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3
Q

How old is the universe estimated to be?

A

13.8 billion yrs

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4
Q

How old is Earth estimated to be?

A

4.6 billion yrs

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5
Q

How old is life on Earth estimated to be?

A

3.5 billion yrs

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6
Q

Define fossil

A

A fossil is a preserved remanent or impression of an organism that lived in the past

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7
Q

Define stromatolite

A

A stromatolite is a layered rock that results from the activity of photosynthetic prokaryotes that bind sediment together.

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8
Q

What atom is highly abundant on earth and in the atmosphere and is most necessary for life on earth?

A

Carbon

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9
Q

What is the role of Carbon, Oxygen, Nitrogen, and Hydrogen?

A

They make up the majority of biological molecules.

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10
Q

What are the four steps of the origin of life?

A
  1. There is the abiotic synthesis of small organic molecules like monomers and amino acids and nitrogenous bases.
  2. The small molecules polymerize into macromolecules like polymers and proteins.
  3. These cells package into protocells, which are cell precursors.
  4. Inheritance originates through the transmission of self replicating molecules.
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11
Q

What is primordial soup and prebiotic soup?

A

The hypothetical set of conditions that led from the prebiotic world to the biotic world.

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12
Q

What year was the Stanley Miller experiment?

A

1953

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13
Q

What did Stanley Miller combine to make what?

A

He combined methane, ammonia, and hydrogen with lightning and synthesized formaldehyde, hydrogen cyanide, amino acids, and hydrocarbons.

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14
Q

What id experiments mimicking the chemical environment of volcanoes yield?

A

Amino acids

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15
Q

What is a monomer?

A

One single molecule

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16
Q

What is a polymer?

A

A group of 10 or more molecules

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17
Q

What is a oligomer?

A

A group of 2-10 molecules.

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18
Q

What are the three ingredients to make a polymer of amino acids/nitrogenous bases without ribosomes or enzymes?

A
  1. Precursor molecules (amino acids and nitrogenous bases)
  2. Thermal energy (heat)
  3. A catalyst (fe2+, pb2+, etc.)
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19
Q

What can we say about clay in terms of catalyzing an organic reaction?

A

Clay is a catalyst of the polymerization of RNA strands.

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20
Q

Define a protocell

A

A droplet with a membrane that had a different interior than the external world.

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21
Q

Are protocells living organisms?

A

no

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22
Q

What are observed living characteristics of vesicles?

A
  1. They can divide spontaneously (reproduction).
  2. They have replication occurring within them (internal metabolism).
  3. They can increase in size (growth)
  4. Membranes are selectively permeable (regulation)
  5. They can perform metabolic reactions using outside molecules (response to environment).
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23
Q

What came first (enzymes vs nucleic acid) according to which theory? Describe the theory.

A

RNA world theory describes that genetic information was at one point stored and transmitted completely by RNA molecules. They were catalysts as well as enzymes, taking a form called ribozymes.

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24
Q

In the RNA world theory, how is inheritance observed?

A

The relative fitness of certain RNA molecules is based on their reproductive rate, and how quickly they can have vesicles split into daughter vesicles.

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25
Q

How can natural selection proceed in the RNA world circumstance?

A

There is variability in reproductive rates (fitness), there are some errors in RNA replication (mutation), and inheritance is observed.

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26
Q

How can fossils provide evidence of evolution?

A

Some fossils are of animals that no longer exist and have gone extinct, some fossils resemble current animals, and organisms can undergo rapid changes (adaptations).

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27
Q

Define biostratigraphy

A

The determination of relative age of sedimentary rock (it is imprecise and innacurate)

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28
Q

Define radiometric dating

A

The determination of absolute age of magmatic rock. This is more precise and accurate.

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29
Q

What is faunal succession?

A

The specific vertical sequence of fossilized flora and fauna that can be identified over large horizontal distances.

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30
Q

What is a biozone?

A

It is an interval of geological strata.

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31
Q

What makes a species a good biomarker for the dating of sedimentary rock?

A

Species that have very specific ecological requirements, that lived for a very short ecological period.

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32
Q

Why is foraminifera a good biomarker for biostratigraphy?

A

It had a wide distribution, it had specific habitats, it had a large morphological diversity, and it was often well preserved.

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33
Q

What does radiometric dating do?

A

It measures changes in isotope composition.

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34
Q

What is an isotope?

A

An atom with the same number of protons but a different number of neutrons.

35
Q

Describe numerically the metrics of radiometric dating.

A

It measures the ratio of carbon-14 to carbon-12 within an organism. As the organism decays, carbon-14 will decay and therefore the measured ratio will be lower. Therefore the lower the ratio the longer the organism has been decaying. Note potassium-40 has a much longer half life, and can be used to measure older specimens.

36
Q

In what direction is there be bias in fossil records?

A

There is bias towards species that lasted for along time or had hard shells and skeletons.

37
Q

What can discontinuity in the fossil record describe? (3)

A
  1. Plate tectonics, erosion, or sedimentary changes.
  2. Changes in climate/habitat like the retreat of seas or glaciers.
  3. Species colonization, extinction, speciation, phenotypic evolution, etc.
38
Q

What is the Cambrian explosion?

A

An explosion of emergence of organisms at the beginning of the Cambrian period roughly 535-525 million years ago.

39
Q

What is the dating of the Burgess Shale? Where is it located?

A

506 million years ago in British Columbia

40
Q

What are the three types of species lifestyle observed in the Burgess Shale?

A
  1. Benthic (Living on the sediment)
  2. Endobenthic (Living within the sediments)
  3. Nektonic (swimming freely)
41
Q

Describe the three major changes of the Cambrian explosion.

A
  1. There was a big transition from soft bodied to hard shelled organisms. This is a defensive adaptation as there was an influx of predation versus a previous abundance of grazing/suspension feeding.
  2. Bilateral symmetry became an evolutionary success (anterior sensing organs-nervous system)
    (anterior predation appendages-prey capturing/feeding)
    (posterior appendages for movement-swimming, crawling, flying)
  3. They underwent adaptive radiation - speciation to fill niches/roles in environment.
42
Q

How are geological and paleontological eras defined?

A

By big changes in abundance/composition of the fossil record ie. mass extinctions.

43
Q

List some causes of mass extinctions.

A

Volcanic events, changes in temperature, meteorites.

44
Q

What is observed after the cascade of ecological events called a mass extinction?

A

After a mass extinction, new adaptative radiation and many new families and genera are always observed.

45
Q

How many mass extinctions have there been in Earth’s history?

A

5

46
Q

What is the name of the third mass extinction? When did it happen?

A

The Permian extinction occurred 252 million yrs ago.

47
Q

What were the percentages of species loss?

A

96% of species lost, 81% marine species, 70% terrestrial vertebrates.

48
Q

What ecological events spurred which consequences in the Permian extinction?

A

Volcanic eruptions in the Siberian traps as well as ocean acidification were described by the lowering of temperatures in the deep ocean followed by a sudden increase in temperature, a decrease in O2 concentration, and increase in CO2 concentration.

49
Q

What is the fifth and most recent mass extinction called? When did it happen?

A

The Cretaceous-Paleogene extinction happened 66million years ago.

50
Q

How many species were lost in the Cretaceous-Paleogene extinction?

A

roughly 75%.

51
Q

What are the key innovations of the fossil record? (6)

A
  1. First cells
  2. Increase in atmospheric O2
  3. Endosymbiosis (eukaryotes)
  4. Sexual reproduction
  5. Multicellularity
  6. Colonization of land
52
Q

How many years ago was it when the first cells appeared?

A

3500 million years ago

53
Q

How many years ago was it when there was an increase in atmospheric O2?

A

2700 million years ago

54
Q

How many years ago was it when eukaryotes were observed (endosymbiosis)?

A

1800 million years ago

55
Q

How many years ago was it when multicellular organisms were observed?

A

1200 million years ago

56
Q

How many years ago was it when sexual reproduction was observed?

A

1000-2000 million years ago

57
Q

How many years ago was it when the first organisms colonized land?

A

485 million years ago

58
Q

How many years ago was it when the animals appeared?

A

635 million years ago

59
Q

How many years ago was it when the humans appeared?

A

6.5 million years ago

60
Q

How can we describe the number of members of every taxonomic level?

A

They all seem to reach an asymptote.

61
Q

What is the number of prokaryote species?

A

We don’t know

62
Q

How many predicted species are there in the world? How many are described?

A

There are a predicted 11,750, 000 species, of which we have described 1,410, 500

63
Q

How many oceanic species have we described?

A

Roughly 200,000

64
Q

What is LUCA? What trait does is it associated with?

A

The Last Common Universal Ancestor is associated with using only L-optical isomers of amino acids. This code is almost universal.

65
Q

How many genes do known proteins share with LUCA?

A

Probably 355.

66
Q

Where was LUCA likely to have lived?

A

In anaerobic deep sea vents rich in CO2 and H2.

67
Q

What is the 3 domains system?

A

The common ancestor of all life derived 3 domains. The domain bacteria was derived, and then a daughter ancestor derived into domain Eukarya and domain Archaea.

68
Q

How many bacteria species are estimated and how many are described?

A

There is an estimated 700,000 species with 10,000 described.

69
Q

What are some characteristics of domain bacteria?

A

-They have a very diverse metabolism
-They are photosynthetic, aerobic, and anaerobic
-They are highly resistant to harsh conditions,
-They can use O2, SO4, etc.

70
Q

What are the laboratory related characteristics of domain bacteria?

A

They are the most studied organism due to ease of cloning, they are easily grown on a petri dish, and they divide (cell division) every 20 minutes at 37 degrees celsius.

71
Q

How many archaea species are estimated and how many are described?

A

50,000 species are estimated, and 500 are currently described

72
Q

Are archaea considered eukaryotes or prokaryotes?

A

Prokaryotes

73
Q

What is special about archaea and methane?

A

They are methanogens, they use CO2 and H2 to produce methane (CH4).

74
Q

What extreme conditions do domain archaea species live in?

A

70-103 degrees Celsius, and pH 5-9.

75
Q

What are uses of archaea domain species?

A

They are the source of DNA polymerase, which is important in labs for heat resistance, and also plays a large role in the polymerization chain reaction, PCR testing for Covid, cloning etc.

76
Q

How many domain Eukarya species are estimated and how many are described?

A

11,000,000 species estimated, 1,400,000 species described

77
Q

What did Eukarya evolve from?

A

Thought to evolve from domain archaea prokaryotes.

78
Q

What cellular structures are present and specific in eukaryotes?

A

Cytoskeletons, Endomembrane systems, nuclei

79
Q

What is serial endosymbiosis?

A

Prokaryotic cells being engulfed by archaea cells to form eukaryotes.

80
Q

What organelles possess a circular DNA, their own transcription/translation proteins, and ribosomes and proteins similar to bacteria?

A

Mitochondrion/Plastids

81
Q

What are the benefits of all the new organelles a Eukarya domain species cell attains?

A

They have a new aerobic metabolic system.

82
Q

What is the colonial hypothesis?

A

Colonies of unicellular organisms of the same species fail to separate or they specialize.

83
Q

What is the symbiosis hypothesis? Is it likely?

A

Cells of different species establish a long term association that is mutually beneficial. It is less likely because it requires cells of different genomes to merge.

Bio Midterm 2 (5 decks)

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