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BIOL 214: Exam 1 > The Origins of Life > Flashcards

The Origins of Life Flashcards

1
Q

Phylogenetic Tree

A
  • Evolutionary history of organisms
  • A graphical representation of these relationships
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2
Q

The Origin of Life - What is Needed for Life?

A
  1. Information storage: presence of a genome that carries the info specifying a phenotype
  2. Compartmentalization: the ability to keep components together and distinguish itself from the environment
  3. Energy acquisition and utilization: metabolism, growth, behavior
  4. Reproduction: the ability to produce more progeny of the same type
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3
Q

[…] can store and transmit information, but can’t perform biological work

A

DNA

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4
Q

{…} can perform biological functions, but can’t propagate

A

[Proteins]

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5
Q

[…] can store information AND do biological work

A

[RNA]

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6
Q

Ribozymes

A

RNA molecules that catalyze reactions like splicing and gene expression–RNA can be both genetic material (DNA like) and a biological catalyst (protein enzymes)

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7
Q

[…] bind and cleave mRNS to prevent it from functioning

A

Ribozymes

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8
Q

Support for the RNA World Hypothesis

A
  • Only known molecule that carries genetic information AND an catalyze chemical reactions
  • In “modern” cells, RNA catalyzes protein synthesis
  • Ribosomes are the most highly conserved component of metabolic machinery
    > built on an RNA framework
  • Several experiments indicate RNA can evolve
    HOWEVER
  • self-replicating RNA has not been demonstrated or discovered (except for very short RNS molecules produced in the lab)
  • RNA is extremely unstable and breaks down easily (major difference as compared to DNA)
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9
Q

Primordial Soup - The Oparin-Haldane Model

A
  1. Assemble simple molecules into building blocks for complex polymers
  2. Assemble polymers that can store information and catalyze reactions
  3. Add membranes and an energy source to make a living organism
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10
Q

Miller-Urey Experiment

A

Demonstrated that many of the compounds necessary for life could be produced in a “pre-biotic” atmosphere
- Recreation of water cycle to synthesize ancient Earth atmosphere

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11
Q

Panspermia

A

The hypothesis that life on Earth originated from microorganisms or chemical precursors of life present in outer space and able to initiate life once reaching a suitable environment

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12
Q

Murchison Meteorite

A
  • In 1969, the meteorite fell to Earth, landing in Australia
  • Contained high levels of organic compounds
  • Came from a parent body that had liquid water
  • Estimated to be 7 BYA, much older than Earth
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13
Q

[…] are essential building blocks of life

A

[Sugars]

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14
Q

Sugars

A
  • Form part of the backbone of nucleic acids
  • Primary energy storage molecules
  • Includes polyols very similar to glucose (a major component necessary for photosynthesis)
  • Implies that early life may have been ‘seeded’ by organic compounds falling from the skies rather than starting from scratch here on Earth
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15
Q

Geological Time Frame
1. The universe is about […] years old
2. The solar system and Earth are about […]
3. The oldest known rocks on Earth are about […]
4. The earliest life evolved about […]

A
  1. [13.7 billion]
  2. [4.6 byo]
  3. [3.8 byo]
  4. [3.5 byo]
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16
Q
  1. Oldest rocks that contain any signs of lie […]
  2. Oldest fossils ever found controversial […]
  3. Five rocks older than […] still exist on Earth
    > any fossils from before that are unlikely to have survived
A
  1. [~3.8 byo]
  2. [~3.5 byo]
  3. [2.5 byo]
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17
Q

So how can we trace back to find common ancestor?

A
  • Know all life descended from a primordial form that used DNA to store heritable information and proteins to express that info
  • Know this because all life uses DNA and proteins and in the same way
18
Q

All life shares:

A
  • The same genetic material (DNA, mRNA, tRNA)
  • The same genetic code (A, C, G, T)
  • The same basic process of gene expression (transcription and translation)
  • The same molecular building blocks (proteins made of 20 amino acids)
    The presence of ribosomes
19
Q

LUCA

A
  • Last Universal Common Ancestor
  • Predates 2 billion years because of fossil evidence of cyanobacteria
20
Q

However, not all genes have same evolutionary history…

A

… each gene (locus) has an independent history
- Recombination
Lateral (horizontal) gene transfer

21
Q

The Age of Earth - A One Year Analogy

A
  • First life appears in late March
  • First marine animals debut in late October
  • Dinosaur become extinct and the mammalian radiation begins on Dec 26
  • The human and chimpanzee lineages diverge about thirteen hours before midnight on December 31
  • Year 1 AD is about 13 seconds before midnight on December 31
22
Q

Types of Rocks

A
  • Igneous rock
  • Sedimentary rock
  • Metamorphic rock
23
Q

Igneous rock

A
  • created from molten material
    > melting of rocks in hot, deep crust and upper mantle
  • formed by the crystallization (solidification of magma or lava)
24
Q

Sedimentary rock

A
  • deposition and solidification of sediments
    > weathering and erosion of rocks exposed at surface
  • formed by the deposition, burial, and lithification
25
Q

Metamorphic rock

A
  • results from the transformation of igneous or sedimentary rock under high pressures and temperatures
    > rocks under high temperatures and pressures in deep crust and upper mantle
  • formed by the recrystallization in solid state of new minerals
26
Q

Relative Dating

A
  • Used to arrange geological events, and the rocks they leave behind, in a sequence
    > does not provide actual numerical dates for the rocks
    Determining if one rock or geological event is older or younger than another, without knowing their specific ages
    > sedimentary rocks do not yield absolute ages
    > use correlation and index fossils
27
Q

Stratigraphy

A

study of layered sedimentary rocks

28
Q

Superposition

A

younger sedimentary rocks laid down on older rocks

29
Q

Original Horizontality

A

Lave and sedimentary rock laid down horizontally; any bending or tipping occurred after deposition

30
Q

Cross-cutting relationship

A

Intruding rocks are younger than host rocks

31
Q

Inclusions

A
  • Boulders or other fragments are older than host rock
32
Q

Faunal Succession

A

Early fossil forms simple; more recent similar to extant taxa

33
Q

Absolute Dating

A
  • can infer actual dates
    > some elements better for different ages
    > also can validate ages using different elements if ages boundaries overlap
  • radioisotopes - isotopes that emit neutrons, protons, and electrons
  • radiometric dating takes advantage of this natural phenomenon
  • Often employ a half-life measurement which is time required for a quantity to reduce to half its initial value
34
Q

Radiometric dating uses […]

A

unstable isotopes

35
Q

Half Life

A

amount of time it takes 50% of the parent isotope to decay into the daughter isotope

36
Q

Dendrochronology

A

biological dating with tree rings
- age determination of trees, of many types of wood, to the exact calendar year
> each ring = one year
- Applications
> paleoncology
> archaeology
> radiocarbon dating

37
Q

Plate Tectonics (continental drift)

A
  • proposed by Alfred Wegener in 1915
  • very well educated from a young age and highly qualified/trained
  • noticed that SE America and W Africa seemed to “fit” together like puzzle pieces
  • Showed that fossils of several species were present in both Brazil and western Africa
    > suggested to him that South America and Africa were in physical contact when fossilized animals and plants were alive
38
Q

Divergent Plate Boundaries

A

the plates are moving apart
- this produces ocean floor (going on in the Atlantic)

39
Q

Convergent plate boundaries

A

the plates are moving towards each other
- This can produce mountains ranges (Himalayas)

40
Q

Transform fault boundaries

A

the plates are grinding past each other
- Earthquakes are common here (California)

41
Q

The continents will probably come together again in the Pacific Ocean in […] million years

A

[~300]

42
Q

Plate tectonics (continental drift)

A
  • explains why similar organisms in similar strata are found on different continents
    > this argument was used to support continental drift before oceanographic data
  • now we have independent data that supports plate tectonics, these biogeographical patterns really provide more support to evolutionary patterns in the fossil record

BIOL 214: Exam 1 (4 decks)

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