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SYSTEMATICS > ORIGIN OF LIFE > Flashcards

ORIGIN OF LIFE Flashcards

1
Q

Theories on the Origin of Life

A

Panspermia
Spontaneous Generation Theory
Chemosynthesis

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2
Q

the biological production of organic compounds from C-1 compounds and nutrients, using the energy generated by the oxidation of inorganic (e.g., hydrogen gas, hydrogen sulfide, ammonium) or C-1 organic (e.g., methane, methanol) molecules.

A

Chemosynthesis

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3
Q

implies that the development of life is probable wherever the proper physical and chemical conditions are in place.

A

Chemosynthesis

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4
Q

seeds everywhere” life exists throughout the Universe; distributed by space dust, meteoroids, asteroids, comets, planetoids, and also by contaminated spacecraft.

A

Panspermia

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5
Q

an extremophilic bacterium and one of the most radiation-resistant organisms known. It can survive cold, dehydration, vacuum, and acid.*

A

Deinococcus radiodurans

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6
Q

It has been listed as the world’s toughest known bacterium in The Guinness Book Of World Records. · Found to withstand harsh space

A

Deinococcus radiodurans

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7
Q

Life can arise from nonliving matter.

A

Spontaneous Generation Theory

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8
Q

proposed that life arose from nonliving material if the material contained pneuma (“vital heat”). Evidences described:

Life can arise from nonliving matter.

  • Bivalves / fishes form spontaneously in mud or sand
  • Insects generated on dew falling on leaves
A

Aristotle (384-322 BC)

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9
Q

supports Spontaneous Generation
Each species arose from an independent event of spontaneous generation. - Spontaneous generation continues today.

A

19th Century Lamarck (1724-1829)

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10
Q

Demonstrated experimentally that microbes would not appear in swan neck flasks protected from dust and other small particles. Spontaneous generation does not happen today on experimental time scales.

A

Pasteur (1822 - 1895)

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11
Q

Conditions on early Earth made the origin of life possible

A

Earth formed about 4.6 billion years ago, along with the rest of the solar system

Bombardment of Earth by rocks and ice likely vaporized water and prevented seas from forming before 4.2 to 3.9 billion years ago

Earth’s early atmosphere likely contained water vapor and chemicals released by volcanic eruptions (nitrogen, nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen, hydrogen sulfide)

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12
Q

Synthesis of Organic Compounds on Early Earth

A

A. I. Oparin and J. B. S. Haldane 1920s

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13
Q

hypothesized that the early atmosphere was a reducing environment and could produce organics

A

A. I. Oparin and J. B. S. Haldane 1920s

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14
Q

suggests that life arose gradually from inorganic molecules, with “building blocks” like amino acids forming first and then combining to make complex polymers.

A

Oparin-Haldane hypothesis

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15
Q

conducted lab experiments that showed that the abiotic synthesis of organic molecules (amino acids) in a reducing atmosphere is possible

A

Stanley Miller and Harold Urey (1953)

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16
Q

simulated early earth with a strongly reducing atmosphere, an ocean, and a hydrologic cycle.

  • Energy inputs via heating & an electrical discharge.
  • Inorganic reactants CH4, NH3, and H2 Amino acids and other organic molecules formed spontaneously under these conditions.
  • The building blocks of living organisms can form spontaneously on short time scales.
A

Mike and Urey Experiment

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17
Q

Amino acids have also been found in meteorites

A

true

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18
Q

RNA monomers have been produced spontaneously from simple molecules

A

true

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19
Q

can spontaneously form vesicles with a lipid bilayer

A

In water, lipids and other organic molecules

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20
Q

Adding ______ can increase the rate of vesicle formation

A

clay

21
Q

exhibit simple reproduction and metabolism and maintain an internal chemical environment

Result protocells

A

Vesicles

22
Q

Chemical and physical processes on early Earth may have produced very simple cells through a sequence of stages:

A

a. Abiotic synthesis of small organic molecules
b. Joining of these small molecules into macromolecules
c. Packaging of molecules into protocells
d. Origin of self-replicating molecules

23
Q

All organisms we know of on Earth today are descended from a common ancestor that lived about 4 billion years ago.

A

true

24
Q

formation of Three Domains of Life

A

1 Last common ancestor of all living things (LUCA)

2 Symbiosis of chloroplast ancestor with ancestor of green plants

3 Symbiosis of mitochondrial ancestor with ancestor of eukaryotes

4 Possible fusion of bacterium and archaean, yielding ancestor of eukaryotic cells

25
Q

The rise and fall of groups of organisms reflect differences in speciation and extinction rates.

A

true

26
Q

Not only geologic time but also continental movement had profound effects on these rates

A

true

27
Q

A continent’s climate can change as it moves north or south

A

true

28
Q
  • Separation of land masses can lead to allopatric speciation
A

true

29
Q

shows that most species that have ever lived are now extinct

A

fossil record

30
Q

The “Big Five” Mass Extinction

A

End Ordovician
Late Devonian
End Permian
End Triassic
End Cretaceous

31
Q

That is, the 1 percent of species on Earth not yet extinct: For the last 3.5 billion or so years, about 99 percent of the estimated 4 billion species that ever evolved are no longer around.

A

true

32
Q

ca. 443 Climate change (Ice)

best 86% of species and 57% of genera, e.g. Trilobites, corals,

Sponges

A

ORDOVICIAN

33
Q

359-380
climate change for >20 million- plus years: volcanic activity in Siberia, reduced oxygen levels in the oceans

etc. 75% of species and 35% of genera; placoderms, corals, trilobites

Small vertebrates, tetrapods → amphibians, reptiles,

A

DEVONIAN

34
Q

251
Volcanic activity in Siberia; global warming; apocalypse unfolded over a span of about 50,000 years.

96 % of species and 56 % of genera; vast forests; amphibians; marine life

Fungi; early ancestors of dinosaurs

A

PERMIAN

35
Q

201
Massive volcanic eruptions in what would become Atlantic Ocean

80% of species and 47% of genera; ribbonlike fish conodont, reptiles

Dinosaurs

A

TRIASSIC

36
Q

65.5
Asteroid; volcanic eruptions

76% of species and 40% Mammals of genera; dinosaurs, ammonites, etc..

mammals

A

CRETACEOUS

37
Q

A number of factors might have contributed to these extinctions i. Intense volcanism in what is now Siberia ii. Global warming resulting from the emission of large amounts of CO2 from the volcanoes iii. Reduced temperature gradient from equator to poles iv. Oceanic anoxia from reduced mixing of ocean waters

A

Permian extinctions

38
Q
  1. Dinosaurs went extinct after living for ca. 165 MY on earth. 2. Planetwide volcanism; large-scale volcanic eruption in the Indian Deccan Traps * a spike in carbon dioxide and a drop in ocean oxygen levels 3. An asteroid (or comet) hit the earth and created a cloud of debris that blocked out sunlight for months. Temperatures dropped and plants died.
A

Cretaceous extinction

39
Q

The ________ is located in the Caribbean Sea near the Yucatan Peninsula of Mexico.

This artists interpretation represents the impact and its immediate effect - a cloud of hot vapor and debris that could have killed most of the plants and animals in North America within hours.

A

65-million-year-old Chicxulub impact crater

40
Q

65 Million years ago the curtain came down on the Age of Dinosaurs when a cataclysmic event led to mass extinctions. This interval of abrupt change in Earth’s history, called the __________, closed the Cretaceous (K) Period and opened the Tertiary (T) Period.

A

K/T Boundary

41
Q

are single-celled organisms that have inhabited the oceans for more than 500 million years. Both living and fossil __________come in a variety of shapes and sizes and occur in many different marine environments.

good indicators of climate change

A

Foraminifera

42
Q

Sediments containing microfossils from after the dinosaurs

A

Post-extinction Layer

43
Q

Dust and ash fallout from the asteroid impact

A

Fireball Layer

44
Q

Material blasted from the crater and deposited here within days to months

A

Ejecta Layer

45
Q

Sediments containing microfossils from the time of the dinosaurs

A

Pre-extinction Layer

46
Q

Scientists estimate that the current rate of extinction is 1,000 to 10,000 times the typical background rate (IUCN)

A

true

47
Q

All of the 17 freshwater fish species endemic to Lake Lanao and its outlet in the Philippines are now Extinct (15 species) or Critically Endangered (Possibly Extinct) (two species). The extinctions were caused by predatory introduced species, compounded by overharvesting and destructive fishing methods.

A

true

48
Q

Evolutionary Milestones

A
  • Life arose from nonlife
  • The first organisms were single cells
  • Speciation has generated the diversity of life
  • Eukaryotes are “cells within cells”
  • Photosynthesis changed the course of evolution - and the planet
  • Multicellular organisms developed relatively late in Earth history.

SYSTEMATICS (12 decks)

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