History of Life Flashcards
(98 cards)
1
Q
6 theories of the origin of earth
A
- gaseous mass hypothesis of kant
- nebular theory of laplace
- planetesimal hypothesis of chamberlain & moulton
- tidal collision hypothesis of jeans & jeffreys
- electromagnetic theory of dr. hannes alfven
- inter-stellar dust hypothesis of otto schmidt
2
Q
age of earth
A
4.54 billion
3
Q
Earth formed when gravity pulled (1) and (2) in to become the (3) from the Sun. Like its fellow terrestrial planets, Earth has a (4), a (5), and a (6).
A
swirling gas and dust; third planet; central core; rocky mantle; solid crust
4
Q
Modern humans first appeared (1) years ago
A
100-150K
5
Q
pieces of evidence of organisms that lived in the past
A
fossils
6
Q
actual remains like bones, teeth, shells, leaves, seeds, spores, or traces of past activities such as animal burrows, nests, and dinosaur footprints, or even the ripples created on a prehistoric shore
A
fossils
7
Q
types of fossils
A
preserved remains
trace fossil
cast fossil
mold fossil
petrified fossil
carbon film
8
Q
impression made in a substance = negative image of an organism
A
molds
9
Q
example of molds
A
shells
10
Q
when a mold is filled in
A
casts
11
Q
examples of casts
A
bones & teeth
12
Q
organic material is converted into stone
A
petrified
13
Q
example of petrified
A
Petrified trees;
Coal balls
14
Q
Preserved wooly (frozen in ice, trapped in tar pits, dried/desiccated inside caves in arid regions or encased in amber/ fossilized resin)
A
original remains
15
Q
example of original remains
A
Wooly mammoth;
Amber
16
Q
Carbon impression in sedimentary rocks
A
carbon film
17
Q
example of carbon film
A
leaf impression on the rock
18
Q
Record the movement and behaviors of the organism
A
trace
19
Q
examples of trace
A
Trackways, tooth marks, gizzard rocks, coprolites (fossilized dungs), burrows and nest
20
Q
six ways of fossilization
A
unaltered preservation
permineralization/petrification
replacement
carbonization/coalification
recrystallization
authigenic preservation
21
Q
small organism or part trapped in amber, hardened plant sap
A
unaltered preservation
22
Q
organic contents of bone and wood are replaced with silica, calcite or pyrite, forming a rock-like fossil
A
permineralization/petrification
23
Q
hard parts are dissolved and replaced by other minerals, like calcite, silica, pyrite, or iron
A
replacement
24
Q
other elements are removed and only the carbon remained
A
carbonization/coalification
25
hard parts are converted to more stable minerals or small crystal turn into larger crystals
recrystallization
26
molds and casts are formed after most of the organism have been destroyed or dissolved
authigenic preservation
27
helps a scientist establish its position in the geologic time scale and find its relationship with the other fossils
dating
28
based upon the study of layers of rocks
relative dating
29
does not tell the exact age
relative dating
30
rules of relative dating
1. law of superposition
2. law of original horizontality
3. law of cross-cutting relationships
31
when sedimentary rock layers are deposited, younger layers are on top of older deposits
law of superposition
32
sedimentary rock layers are deposited horizontally. If they are tilted, folded, or broken, it happened later
law of original horizontality
33
if an igneous intrusions or a fault cuts through existing rocks, the intrusion/ fault is YOUNGER than the rock it cuts through
law of cross-cutting relationships
34
determines the actual age of the fossil
absolute dating
35
uses radioactive isotopes like (1) and (2)
absolute dating; carbon-14; potassium-40
36
considers the half-life
absolute dating
37
the largest division of the geologic time scale; spans hundreds to thousands of millions of years ago (mya)
eon
38
division in an (1) that spans time periods of tens to hundreds of millions of years
era
39
division of geologic history that spans no more than one hundred million years
period
40
smallest division of the geologic time scale characterized by distinct organisms
epoch
41
geologic time scale sequence
eon, era, period, epoch
42
4.5 billion years & about 88% of the Earth’s history
precambrian
43
Earth coalesced from a cloud of dust into a planet, formation of Earth, high temperature, ball of gasses
hadean
44
- Molten rocks cooled down
- Gasses provided cooler atmosphere
- It was early in the Archaean that life first appeared on Earth.
- Our oldest fossils date to roughly 3.5 billion years ago, and consist of bacteria microfossils.
- Colonies of photosynthetic bacteria which have been found as fossils in Early Archaean rocks of South Africa and Western Australia.
- Stromatolites are layers of calcium carbonate that form in warm, shallow seas by the activities of photosynthetic bacteria.
archean
45
- Temperatures cooled down significantly
- Cyanobacteria existed (w/o oxygen) and oxygenated the Earth
- (1): oldest fossils of larger, multicellular, soft-bodied marine animals.
proterozoic; Ediacara fauna
46
- approximately 541.0 million years ago.
- Five major extinction events The reasons for the extinctions vary but all reasons tend to cause shifts in Earth's environmental conditions, making it difficult for some species to survive.
phanerozoic
47
- Started more than 540 mya
- First surge of life, from the first fish to the evolution of land-dwelling organisms.
paleozoic
48
- burst of diversity
- Hard external skeletons protected trilobites, clams, snails, and sea urchins from predators.
cambrian explosion
49
- Invertebrates filled the oceans
- Straight-shelled cephalopods, trilobites, snails, brachiopods, and corals in a shallow inland sea.
- Plants colonized the land for the first time was the “Golden Age” of cephalopods and brachiopods (a clam-like shellfish).
ordovician period
50
- This was the “Golden Age” of cephalopods and brachiopods (a clam-like shellfish).
- The first land plants developed, and the first arthropods (scorpion-like invertebrates) ventured onto land.
silurian period
51
- (1) - the naked-seed plants - developed. Gymnosperms like Glossopteris developed.
- (2) are long-lived relics of the ancient family of naked-seed plants, so are conifers.
devonian period; first seed plants; ginkgos
52
Reptiles evolved and they were the first animals that could reproduce on dry land
carboniferous period
53
peat swamps common, with scale trees, seed ferns, scouring rushes, and large dragonflies
pennsylvanian
54
amphibious tetrapods multiply wildly; many grow enormous in the high humidity and oxygen Giant insects and myriapods flourish in the high humidity and oxygen
MISSISSIPPIAN
55
- (1), a carnivorous amphibian
- Pangaea is formed
- Temperature were extreme, and the climates was dry
- Plants and animals evolved adaptations to dryness such as waxy leaves or leathery skin
- Ended with mass extinction
permian period; eryops
56
“Middle life”
Started more than 280 mya
“Age of Reptiles”
“Era of Dinosaurs”
High C and O; smaller mammals
mesozoic era
57
- First dinosaurs and mammals;
- Huge seed ferns and conifers dominated the forest.
- Pangaea broke into two new continents Laurasia and Gondwanaland
triassic period
58
- Golden Age for Dinosaurs
- Earliest birds evolved from reptiles
- Intense volcanic activity
jurassic period
59
- Plesiosaurs infested the beaches
- Cretaceous -Tertiary Boundary
- Many species and genera, including the dinosaurs, died out at end of Cretaceous
- One hypothesis: Earth was hit by a meteorite - at Chixulub, in the Yucatan area of Mexico
cretaceous period
60
- Started 65 mya and continues to the present
- “Age of Mammals”
cenozoic era
61
Dating tertiary period The Earth's climate was warmer than today, but cooler and drier than the epochs immediately preceding and following it. Europe and North America were connected, as were Asia and North America at times.
paleocene
62
Early in the (1), the global climate remains warm. As the continents move ever closer to their present-day positions, this plate activity alters ocean and air circulation patterns. By the end of the (1), temperatures cool considerably and a drying period commences.
eocene
63
horses, antelopes, cats, oreodonts
oligocene
64
horses, rhinoceri, and elephants.
miocene
65
a time of global cooling after the warmer Miocene. The cooling and drying of the global environment may have contributed to the enormous spread of grasslands and savannas during
pliocene
66
- mammals successfully colonized all environments
- 4.4-0 m.y.a.: Hominids diverged from an early ape-like family.
pleistocene
67
4.4 (bipedal, erect forest dweller)
Ardipithecus ramidus
68
4.2-3.9 (bipedal, apelike skull)
Ardipithecus anamensis
69
(“Lucy”) - 3.9-2.8 (bipedal, apelike face with sloping forehead, human-like bodies
Australopithecus afarensis
70
2.2-1.6 m.y.a. (used stone tools, so may be related to Homo sapiens, but skull is like australopithecines)
homo habilis
71
1.8-0.4 m.y. (Peking man, Java man: developed large brains, tools, weapons, fire, and learned to cook food.)
homo erectus
72
500-200 t.y.a.
Homo sapiens archaic
73
200-30 t.y.a (teeth and brain similar to ours, but DNA different, burial sites suggest they practiced some form of religion.
Homo sapiens neandertalensis
74
Homo sapiens sapiens - 12,000- present
holocene
75
boundary between the Paleozoic and Mesozoic eras (96%)
permian
76
reasons for mass extinction
1. Extreme volcanism producing enough Co2 to cause global warming
2. Ocean acidification
3. Eruptions added Phosphorous – stimulated bacterial growth (bacteria uses oxygen, Oxygen levels drop
77
fallout from a huge cloud of debris that billowed into the atmosphere when an asteroid collided with Earth
iridium
78
how did the first living cells appear
1. The abiotic (nonliving) synthesis of small organic molecules
2. The joining of these small molecules into macromolecules
3. The packaging of these molecules intro protocells
4. The origin of self-replicating molecules that eventually made inheritance possible
79
small organic molecules
amino acids and nitrogenous bases
80
macromolecules
proteins and nucleic acids
81
droplets with membranes that maintained an internal chemistry different from that of their surroundings
protocells
82
1. Earth’s early atmosphere was a reducing (electron-adding) environment
2. Energy used came from lightning and UV radiation
alexander oparin & john burdon sanserson haldane (1920s)
83
“primitive soup”
haldane
84
- Tested the Oparin-Haldane hypothesis
- Simulated early Earth conditions.
- His apparatus yielded a variety of amino acids found in organisms today, along with other organic compounds.
stanley miller & harold urey (1953)
85
areas on the seafloor where heated water and minerals gush from Earth’s interior into the ocean. Some of these vents, known as “(1)” release water so hot (300–400°C) that organic compounds formed there may have been unstable.
hydrothermal vents; black smokers
86
other deep-sea vents, called (1), release water that has a high pH (9–11) and is warm (40–90°C) rather than hot, an environment that may have been more suitable for the origin of life
alkaline vents
87
presence of small organic molecules, such as amino acids and nitrogenous bases, is not sufficient for the emergence of life as we know it
Abiotic Synthesis of Macromolecules
88
All organisms must be able to carry out both reproduction and energy processing (metabolism)
protocell
89
major constituent of the fossil record of the first forms of life on earth. They are layered rocks that were formed from certain activities of certain prokaryotes
stromatolites
90
blue-green algae, were the main photosynthetic organism for a billion of years and remain one of the most important organisms today
cyanobacteria
91
unofficial unit of geologic time, used to describe the most recent period in Earth's history when human activity started to have a significant impact on the planet's climate and ecosystems
anthropocene epoch
92
occurs when the nuclei of unstable atoms break down, changing the original atoms into atoms of another element
radioactive decay (half-life)
93
the amount of time it takes for half of the atoms of a substance to decay into another element.
half-life
94
Used for dating biological remains.
Decay occurs upon death.
carbon-14
95
half-life of carbon-14
5,730 yrs
96
Used for dating rocks
uranium-238
97
half-life of uranium-238
4,500,000,000 years
98
characteristics of early life
self-replication
nutrition
