ORIGIN OF LIFE

Question 1

Theories on the Origin of Life

Answer 1

Panspermia
Spontaneous Generation Theory
Chemosynthesis

Question 2

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.

Answer 2

Chemosynthesis

Question 3

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

Answer 3

Chemosynthesis

Question 4

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

Answer 4

Panspermia

Question 5

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

Answer 5

Deinococcus radiodurans

Question 6

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

Answer 6

Deinococcus radiodurans

Question 7

Life can arise from nonliving matter.

Answer 7

Spontaneous Generation Theory

Question 8

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

Answer 8

Aristotle (384-322 BC)

Question 9

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

Answer 9

19th Century Lamarck (1724-1829)

Question 10

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.

Answer 10

Pasteur (1822 - 1895)

Question 11

Conditions on early Earth made the origin of life possible

Answer 11

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)

Question 12

Synthesis of Organic Compounds on Early Earth

Answer 12

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

Question 13

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

Answer 13

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

Question 14

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

Answer 14

Oparin-Haldane hypothesis

Question 15

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

Answer 15

Stanley Miller and Harold Urey (1953)

Question 16

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.

Answer 16

Mike and Urey Experiment

Question 17

Amino acids have also been found in meteorites

Answer 17

true

Question 18

RNA monomers have been produced spontaneously from simple molecules

Answer 18

true

Question 19

can spontaneously form vesicles with a lipid bilayer

Answer 19

In water, lipids and other organic molecules

Question 20

Adding ______ can increase the rate of vesicle formation

Answer 20

clay

Question 21

exhibit simple reproduction and metabolism and maintain an internal chemical environment

Result protocells

Answer 21

Vesicles

Question 22

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

Answer 22

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

Question 23

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

Answer 23

true

Question 24

formation of Three Domains of Life

Answer 24

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

Question 25

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

Answer 25

true

Question 26

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

Answer 26

true

Question 27

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

Answer 27

true

Question 28

- Separation of land masses can lead to allopatric speciation

Answer 28

true

Question 29

shows that most species that have ever lived are now extinct

Answer 29

fossil record

Question 30

The "Big Five" Mass Extinction

Answer 30

End Ordovician Late Devonian End Permian End Triassic End Cretaceous

Question 31

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.

Answer 31

true

Question 32

ca. 443 Climate change (Ice) best 86% of species and 57% of genera, e.g. Trilobites, corals, Sponges

Answer 32

ORDOVICIAN

Question 33

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,

Answer 33

DEVONIAN

Question 34

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

Answer 34

PERMIAN

Question 35

201 Massive volcanic eruptions in what would become Atlantic Ocean 80% of species and 47% of genera; ribbonlike fish conodont, reptiles Dinosaurs

Answer 35

TRIASSIC

Question 36

65.5 Asteroid; volcanic eruptions 76% of species and 40% Mammals of genera; dinosaurs, ammonites, etc.. mammals

Answer 36

CRETACEOUS

Question 37

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

Answer 37

Permian extinctions

Question 38

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.

Answer 38

Cretaceous extinction

Question 39

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.

Answer 39

65-million-year-old Chicxulub impact crater

Question 40

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.

Answer 40

K/T Boundary

Question 41

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

Answer 41

Foraminifera

Question 42

Sediments containing microfossils from after the dinosaurs

Answer 42

Post-extinction Layer

Question 43

Dust and ash fallout from the asteroid impact

Answer 43

Fireball Layer

Question 44

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

Answer 44

Ejecta Layer

Question 45

Sediments containing microfossils from the time of the dinosaurs

Answer 45

Pre-extinction Layer

Question 46

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

Answer 46

true

Question 47

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.

Answer 47

true

Question 48

Evolutionary Milestones

Answer 48

* 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.