Exam 2 COPY Flashcards
(241 cards)
1
Q
Law of Superposition
A
Oldest strata of undeformed sequences at the bottom; youngest at the top
2
Q
Original age of Earth (later proved false)
A
3000 years old
3
Q
What is strata made from?
A
Fluids like fresh and salt water; not from lava
4
Q
What can strata be used for?
A
Fossils, matching fossils from different locations, understanding times scales
5
Q
Radiometric dating
A
20th century; used C14 which Is the heaviest isotopes
6
Q
3 discoveries that proved Earth was older than originally thought
A
1) Existence of distinct layers of strata of sedimentary rock
2) Law of superposition
3) Strata can be correlated based on fossils
7
Q
One problem proposed by May about Darwin’s evolution
A
Calvin’s estimations of Earth’s age were wrong; evolution can occur because of the very old age of Earth
8
Q
One problem that May proposed about Darwin that has not been resolved
A
Evolution and the idea of altruism
9
Q
Four principal time units
A
Eons, Eras, Periods, Epochs (EEPE)
10
Q
Eons (2)
A
Precambrian, Phanerozoic
11
Q
Eras in Phanerozoic eon (3)
A
Paleozoic, Mesozoic, Cenozoic
12
Q
Periods in Paleozoic era (6)
A
Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian
13
Q
Periods in Mesozoic era (3)
A
Triassic, Jurassic, Cretaceous
14
Q
Periods in Cenozoic era (2)
A
Tertiary, quaternary (we are in this)
15
Q
Mnemonic for Paleozoic and Mesozoic periods
A
Cows Often Sit Down Carefully. Perhaps Their Joints Creak?
16
Q
Epochs in Tertiary (5)
A
Paleocene, Eocene, Oligocene, Miocene, Pliocene
17
Q
Epochs in quaternary (2)
A
pleistocene, holocene
18
Q
Where did the names of the EEPEs came about?
A
The name for the EEPEs came from where the strata, rocks, and fossils were first discovered and dug up
19
Q
What is the name Cambria an old name for?
A
Wales
20
Q
What is 3/4 of the earth’s history?
A
Precambrian Eon
21
Q
What occurred in the precambrian eon (4.5-4.6 By a)?
A
- Origin of Life on Earth
- Origin of Prokaryotes
- Origin of Eukaryotes
- Evolution of sex
- Evolution of multicellularity
- Formation of the moon
- Bombardment phase
- Increase in oxygen
22
Q
What was the precambrian eon lacking?
A
Precambrian eon was lacking both fossils and fossil bearing rocks because the organisms were soft bodied and the rocks were too hard or destroyed the fossils
23
Q
Where were the first fossils found?
A
Cambria
24
Q
What is 1/4 of earths history?
A
Phanerozoic Eon
25
Characteristics of the Phanerozoic eon
- Fossils Abundant
| - Evolution of higher plants and animals with major taxa appearing at or near base of the Cambrian
26
Why was major taxa appearance a problem for Darwin?
It undercut his idea that evolution was gradual
27
What was the formation of the moon like?
Creation disk that has a lot of rocky stuff in it that condensed into sun or planets. The moon was formed because the earth was hit with a very large object and the moon was shot off into space.
28
T of F: The moon was originally part of earth?
True
29
Bombardment Phase
- Ended 4-3.8 Bya
| - Called bombardment because of colliding objects
30
What did the Earth look like during the bombardment phase?
The earth wasn't covered in molten lava. it was apparently cool enough to walk on but the earth did have occasional sterilzing periods where it would become incredibly hot
31
How did the sun come about?
A nebular cloud condensed to become the sun and the gravity was sufficiently large so the atoms became sufficiently close and one day the sun turned on and there was an enormous explosion
32
What was the earliest life?
Microfossils
33
What is the signature of photosynthesis?
12c enriched organic matter
34
What was the oldest microfossils?
3.5 Bya
| Prokaryotes
35
All things carbon isotopes
Carbon has many different isotopes and carbon 12 is the most common. Less common more heavy is carbon 13.
- The ratio of C12 to C13 allows us to infer existence of life
- The presence of organic matter that are carbon deposits with higher concentration of C12 are said to be the signature of photosynthesis because the enzyme in photosynthesis prefers C12 to C13, the lighter isotope
- If you have dark matter, and you find the ratio of C12 to C13 and C12 is higher than C13, this means that there are traces of plant life and animal life in the sample compared to the earth ratio at large
36
T or F: The oldest evidence of living creatures based on the isotopic ratio is a little bit older than the oldest microfossil
True
37
T or F: The original atmosphere on earth had oxygen
False; it didn't have any oxygen
38
What is the waste product of Photosynthesis?
Oxygen
39
What has to happen for oxygen to increase in the water and the air?
The oxygen has to first rust all available metals. This is called Great Rusting
40
What was rusted in the ocean?
Banded Iron Formations (BIFs)
41
What was rusted on the land?
Red beds
42
How much oxygen was at the beginning of the Cambrian?
10% oxygen
43
T of F: The rise of oxygen was gradual
False; the rise of oxygen was not gradual and occurred in a two step process
44
Why did the ocean take longest to increase the amount of oxygen?
The ocean was too deep to have sunlight reach the plants to begin photosynthesis
45
Cambrian Explosion
Major phyla appear at or near the base of the Cambrian 550 Mya. Most of modern phyla appeared at once.
46
Main feature of the Ordovician
Jawless fishes abundant
47
Features of silurian
- Jawed fishes
- Sea scorpions
- First land plants
- Terrestrial insects
48
Main feature of the Devonian
Terrestrial vertebrates
49
Main feature of the Permian
"Mammal-like" reptiles
50
End-Permian characterized by:
Large mass extinction
- 96% of all species lost
- Coincident vulcanism/anoxia: Siberian traps
51
What period do our ancestors come from?
Permian
52
Mesozoic Era characterized by
- Mammals and dinosaurs
- Mammal-like reptiles dominate
- Flowering plants and birds evolve
- Chicxulub impact
53
Chicxulub impact
- 65 Mya
- Most likely killed off the dinosaurs
- Confusion because scientists aren't sure if dinosaurs were killed off from this one event or if they were on their way out
54
What is the support for the theory that dinosaurs were already on their way out in the chicxulub impact during the mesozoic era?
Deccan traps when India moved over a hot spot-killed dinosaurs little by little
55
In what era of the Phanerozoic eon did amniotes come about?
Palaeozoic
56
Amniotes
Reptiles, birds, and mammals that lay eggs or have amniotic membranes
57
When did mammals arise?
Triassic period in the Mesozoic era in the Phanerozoic eon
58
When did the platypus arise?
Late jurassic where protherians (platypus, echidna) and therians came about
59
Characteristics of the Cenozoic era
- Post-Chicxulub radiation of surviving Mesozoic mammals and birds
- Placental mammals dominate
- Man evolved in Africa
- Megafauna extinction
- OOA
- Agricultural Revolution -> self-domestication
60
When and where did man first evolve?
In Africa during the Pleistocene period. First Homo Erectus makes its way out of Africa and invades Asia and then H. sapiens do the same
61
T or F: Bipedalism precede large brains
True
62
Which dinosaurs made it out of the Chicxulub impact and which were killed? Avian vs. Non avian
Avian: made it out of chicxulub impact and had radiation from impact
Non Avia: Killed from chicxulub impact
63
Significance of South America during the Cenozoic Era
- Mammalian fauna consisted of archaic placental ungulates (hoofed mammals) and marsupial carnivores
- Home to giant flightless terror birds
- Unique biota died out following formation of the Isthmus of Panama and invasion by North American species
64
Placental ungulates =
hoofed mammals
65
T or F: Ungulates became prey
False; ungulates became predators
66
T or F: Carnivals closely related to marsupials
True
67
Significance of Australia during the Cenozoic Era
- Home to the world's only living monotremes (egg laying mammals)
- Marsupials (descended from opossums) dominate to this day
68
Story to remember Thylacosmilus
- Thylacosmilus is an extinct South American metatherian carnivore superficially similar to North American saber tooth cats
- STORY: Road runners come to Schaffer's backyard and eat the cat kindle by snapping at it with their beaks
69
How were Neanderthals terminated?
Homo sapiens interbred with Neanderthals and terminated them
70
What happened when humans arrived on the Bering Straight Land bridge from NA to SA?
Humans caused the extinction of the Pleistocene megafauna in NA including mammoths and lions
71
What is the OOA and what is it supported by?
- "Out of Africa"
- Supported by genetics and paleontology
- Starts in Africa and humans travel to Asia, Australia, then NA and SA
- Recently updated; earlier colonization of Asia
72
Two theories that account for Pleistocene megafauna extinction?
- Overkill
- Climate Change
- Both theories are not mutually exclusive
73
Characteristics of Agricultural Revolution
- Hunter gatherers become farmers
- Rise of kings, armies, and tax collectors
- Selection of docility - man becomes a domesticated species
- Recall fox farm experiment (correlated characteristics)
- In general: Self-domestication
74
Example of Pleiotropy
Chimp at London zoo as a young female. In dress and rode bike: when chimp grew older, the jaw grows and teeth get sharper -> not so cute.
-When you select for one thing you select for many things: Pleiotropy (one trait can do a lot of things)
75
Changing physical environment
- Increase solar output by 25% over 4.5by
- Recurrent changes in earth's orbit and orientation
- Drifting continents
- Changing climate including periods of extensive glaciation
- Changing levels of atmospheric oxygen and CO2 due to geological and biological processes
- Cataclysmic impacts
76
T or F: The orbit of the earth is elliptical and changes on time scales?
True
77
What continent forms and drifts during the Cambrian?
Gondwana
78
What continent forms in the Permian and then what does it divide into?
Pangea and then it divides into Laurasia and Gondwana
79
What ocean forms during the Cretaceous separating what two modern day countries/continents?
The North Atlantic which separates Europe and NA
80
What is the consequence of India and Australia drifting north and east during the Cenozoic?
India eventually collides with Asia which then forms the Himalayas
81
Primordial Sun
Beginnings of the sun
82
Accretion:
Stuff coming together
83
How was the Earth formed?
The Earth was formed from accretion over a period of uncertain duration
84
Facts about the earth's formation
- Level of violence was uncertain
- If the process was fast or if the moon was created from an enormous impact then the entire surface remelted
- If not, only the core melted
- The melting vaporized many oceans
85
What gas predominated in the first atmosphere?
Hydrogen which was part of the original nebula
86
What was the second atmosphere a product of?
- Outgassing - Volcanic eruptions
- Impacts from meteors etc.
- No free oxygen
- Reducing or weakly oxidizing
- H2 (maybe) and H2O
87
Benefits of impacts of comets and meteorites
- They deliver water and gasses
| - Source of organic and simple
88
Why is our earth filled with oxygen?
Oxygen photosynthesis meaning, oxygen came from photosynthesis performing organisms
89
What biological activities are the cause of present day oxygen-rich atmosphere?
- The great rusting
- Oxidation of bacteria-produced CH4
- "Snowball earth" consequent to reduced greenhouse effect a possible result
90
Consequence of increased O2
Most organisms perished
91
Significance of the first class of organisms that survived the oxygen catastrophe
A few organisms, including ancestors of mitochondria, "learned" to utilize/detoxify oxygen and other products of aerobic metabolism
92
Significance of the second classy of organisms that survived the oxygen catastrophe
Mitochondria is a source of oxidants, against which eukaryotic cells mount enzymatic defenses
-This is the reason why we can't get cut with a rusty nail. The oxygen somewhat attacks us.
93
Stromatolites: what are they and what are their contributions
- Bacterial mats
- Important to the oxidation of earth's atmosphere
- They contain cyanobacteria that produces O2 -byproduct of oxygenic photosynthesis
94
What are chloroplasts of modern plants descended from?
Cyanobacteria
95
What environment did stromatolites survive in?
They were originally thought to be extinct but they survived in high salinity areas to protect them from grazing invertebrates such as worms and snails
96
What is the Oparin-Haldane Hypothesis?
In the 1920s Oaprin and Haldane independently proposed that life formed spontaneously under pre-biotic conditions.
-Both assumed that life evolved from proteins
97
What did Oparin believe the carbon source was on Earth?
Methane
98
What did Haldane believe the carbon source was on Earth?
Carbon dioxide
99
What did Oparin postulate?
Oparin postulated spontaneous appearances of oily droplets (coacervates) that subsequently evolved into cells
100
What did Haldane imagine regarding the spontaneous origin of life?
Haldane imagined gradual increase in concentration and complexity of pre-biotic molecules in solution
-Caused by intense levels of UV radiation reaching earth's surface prior to development of ozone shield
101
T or F: UV light can create and destroy ozone
True; ozone creation and destruction varied over time with the varying development of the sun
102
Purpose of the Urey-Miller Experiment
They wanted to test the Oparin-Haldane hypothesis
103
Urey-Miller Experiment
Passing an electric spark (simulates lightning) through a reducing atmosphere results in the formation of amino acids - mostly glycine and alanine
104
Urey-Miller Experiment results
- Stunning confirmation of Oparin-Haldane hypothesis
- Interpreted as supporting Haldane's idea that the primordial ocean was a "dilute soup" of organics that precipitated out of the atmosphere
105
What supports the pre-biotic synthesis of biological molecules?
-Existence of carbonaceous chondrites
106
T or F: What is good for primitive Earth also good for outer space
True
107
Carbonaceous chondrites
- meteorites containing significant concentrations of organic compounds that landed near Murchison, Victoria, Australia
- Presence of guanine and adenine the nucleobases
108
List difficulties of the origin of life (4)
- Polymerization
- Primordial atmosphere insufficiently reducing
- Insufficient time
- Nucleic acid synthesis impeded by high temp
109
Polymerization
Peptide formation requires condensation reactions (H2O removed)
110
What is the problem with polymerization?
In aqueous solutions, rate of polypeptide dissociation far exceeds the rate of condensation
111
T or F: If atmosphere weakly oxidizing (CO2 and N2), biomolecule yield greatly diminished
True
112
Problem of primordial environment
Primordial environment not producing sufficient amount of carbon and oxygen in substances
113
Two theories of result of insufficient reducing of the atmosphere
Panspermia (microorganisms or chemical precursors of life present in outer space and able to initiate life on reaching a suitable environment)
and Early habitable universe
114
Significance of when bombardment phase ended
Ended around the same time scientists expected traces of organic life to start being found
115
What can first? Microfossils or biogenic carbon?
1st microfossils date to 3.5 By and biogenic carbon came even earlier
116
What did the insufficient time difficulty say about the window of opportunity for complex life forms to evolve?
The window of opportunity was very narrow
117
Theory: Subsurface origins
Theory that life started beneath the surface of the earth; Semi backed up by that fact that we know archaea lived in the earth's surface
118
T or F: Previously everyone thought that the information being passed on from one generation to the next was nucleic acids but its actually proteins
False; Previously everyone thought that the information being passed on from one generation to the next was proteins but its actually nucleic acids
119
Difficulty regarding early nucleic acids
Spontaneous synthesis of nucleic acids was impeded by high temperatures
120
Mineral cell theory
Holds that metabolism originated in tiny cavities in minerals such as FeS. Cell membranes came later
121
Theories for connecting metabolism and information storage
- Mineral cells
| - Coacervates (egg and oil idea)
122
Packaging metabolism inside a membrane to avoid the dilution problem is a consequence of...
The 2nd Law
123
Numerous hypotheses proposed since Urey-Miller
- RNA world
| - Lipid world
124
Where did RNA and Lipid world come from?
Hydrothermal vents as environments where life may have evolved due to the fact that it provided both energy and chemical building blocks
125
What are hydrothermal vents home to?
Thermophilic Archaea
126
T or F: Miller argued that thermophilic is a derived trait
True; He backed up this theory with the fact that high temperatures degrade macromolecule precursors (Sugars and nucleobases) and the results of the 25 year freezer expt.
127
What is the 25 year freezer experiment?
Miller added ammonia and HCN and put it in the freezer for 25 years, it produced amino acids and nucleobases - freezing concentrates impurities- promotes assembly
128
T or F: Water all freezes at once
False; It freezes little by little, this is how Miller's freezer experiment worked
129
RNA world Theory
1. RNA (messenger and ribosomal) manufactures proteins
2. RNA can self-replicate in vitro
3. RNA can produce DNA via reverse transcriptase
4. Single stranded RNA forms 3-D structures that can catalyze reactions, e.g., ribozymes remove introns
130
Abiogenesis
Spontaneous generation of living things
131
What solved the "what came first: proteins or DNA?" and what is the answer?
RNA world theory; RNA came first
132
Traditional RNA world scenario
1. RNA form ribose and nucleotide
2. RNA "learns" to self-replicate
3. RNA catalyzes protein synthesis
4. Proteins facilitate
- More efficient RNA self- replication
- Double-stranded RNA that evolves into DNA
5. DNA assumes role of information storage. RNA relegated to transcription/translation
6. Chemistry packaged in a membrane
133
Aside from the RNA world theory, what are more recent studies suggesting?
- rRNA and proteins may have evolved in parallel before formation of first ribosome
- Early protein synthesis independent of RNA
- In either case, packaging may have come first- or not.
134
T or F: High energy compounds (ATP, GTP) are ribonucleoside (nucleobases + sugar) triphosphates
True
135
T or F: Deoxyribonucleotides (nucleobases + sugar + phosphare) enzymatically synthesized from RNA precursors
True
136
Riboswitches
Regulatory segments of messenger RNA that alter/block protein production via translation or transcription
137
Big question about the origin of life?
Was the origin of life a wildly improbable event (frozen accident) or an inevitable consequence of changing conditions (emergent property)?
138
Emergent properties
Thinks: The brain thinks but neurons don't
139
Auxiliary hypothesis
Rescuing the idea you really thought/wanted; being the parent and mediated your experiment
140
Characteristics of eukaryotes
- Lack bacterial wall
- DNA organized into chromosomes; DNA wrapped around histones
- Possesses cytoskeleton, digestive vesicles, and membrane-encased organelles
141
When did the earliest known eukaryote come about?
1750 Mya
142
T or F: Eukaryotic DNA is wrapped around histones
True
143
T or F: mitochondria and chloroplasts have nothing to do with free-living prokaryotes
False; Widely agreed that mitochondria and chloroplasts descended from free-living prokaryotes - have bacteria-like DNA
144
Symbiogenesis First Theories (2)
- Ring of Life Hypothesis
| - Chronocyte Theory
145
Ring of Life Hypothesis
- Eukaryotes arise vis fusion of an archaebacterium (archaea) and eubacterium (bacteria)
- Archaebacterium became the nucleus
- Consistent with genomic comparisons of yeast and bacteria: Genes coding for nuclear functions from Archaea; genes coding for cytoplasmic function, from Bacteria
146
Chronocyte Theory
- Extinct RNA-based eukaryote lineage (chronocyte) evolved cytoskeleton and phagocytosis
- Engulfed archaea became DNA based nucleus
- Explains eukaryotic signature proteins (ESPs) -membrane systems, ER, cell cycle, etc. unique to Eukaryotes - as chronocyte heritage
- Explains spatial separation of transcription (nuclear) and translation (cytoplasmic)
147
What is similar for both the Chronocyte Theory and the Ring of Life Hypothesis?
They both agree that mitochondria and chloroplasts acquired later
148
What is the mitochondria First Theory?
Nucleus formation in eukaryote ancestors triggered by engulfing mitochondrial ancestors
149
Phagocytosing Archeon Theory (PhAT)
- Now extinct Archaea evolve phagocytosis
- Mitochondrial ancestor engulfed
- Mitochondria DNA contaminates host cell DNA - source of eukaryotic introns
150
Spliceosomes
Molecular machines formed of proteins and small nuclear RNA molecules that remove introns from messenger RNA before translation
151
Evolution of Nuclear membrane
- Protected archaean's DNA from increased LGT consequent to symbiont cell lysis
- Prevented intron translation (i.e. before their removal of spliceosomes)
152
What are the three steps of the "Pinching off" Theory?
1. Loss of cell wall
2. Invagination of cell membrane
3. Nucleus pinches off
153
What does the "Pinching off" theory say about nucleus and cytoskeleton?
They arose de novo
154
Autogenous models
Prokaryote that basically created a nucleus and then mitochondria and chloroplasts came later.
155
T or F: Viruses RNA world relics - originally all used RNA
True
156
T or F: Viruses have not evolved DNA
False; Viruses evolved DNA in a co-evolutionary arms race with their RNA hosts
157
T or F: Three such viruses independently converted (reverse transcription) different RNA hosts to DNA
True; The descendants of the converted checks ancestral to the three domains
158
T or F: Viruses are considered non-life
True, however, that may be starting to crack
159
Why is the viruses = non-life consensus going away?
Giant (double stranded DNA) viruses produce proteins normally associated with cellular physiology including enzymes that synthesize tRNA
160
T or F: Giant viruses have genomes as large as or larger than parasitic prokaryotes
True
161
What are Giant viruses descendants of?
Early, now extinct, domains of life as they also code for non-virus activities such as sugar metabolism and DNA repair
162
Reasons for why the stage was set for the evolution of Metazoa with the evolution of eukaryotic cells?
- Gene based phylogenies: Major groups diverged before the Cambrian
- Paleontology: few metazoans at the base of the Cambrian. Dramatic increase in size, numbers and diversity thereafter.
- 15 my into the Cambrian, 80_+ skeletal taxa
- Trilobites: 530 Mya
- Except for bryozoans, all major groups appear in the Cambrian
163
Why was the sudden appearance of extensive fossils in the Cambrian concern to Darwin?
- He viewed such an abrupt increase in biotic diversity as contradicting evolutionary gradualism
- Imagined abundant Precambrian life, the remains of which were not preserved
164
T or F: Since Darwin's time a number of late Precambrian (565-543 Mya) fossil assemblages have been discovered
True; These so-called Ediacaran faunas consist of soft-bodied forms and trace fossils. The only modern group represented for sure is Cnidaria (jellyfish)
165
T or F: Some Ediacaran animals may have persisted into the mid-Cambrian
True
166
The extent to which Precambrian "animals" ancestral to Cambrian assemblages _____ .
uncertain
167
T or F: If the modern taxa evolved shortly before they appear, molecular data overestimate divergence times
True
168
T or F: If the molecular evidence regarding Cambrian taxa, absent distinguishing skeletal features, is true, then Cambrian taxa evolved long before the end of the Precambrian
True
169
Two possibilities now that we know the Cambrian explosion is real
1. Most of the major taxa really did originate over 10-15 million years
2. Lineages that had previously diverged radiated into new niches and acquired skeletons
170
Factors to account for explosive morphological change in the Cambrian
- Increasing concentration of oxygen made possible larger size and the secretion of hard parts
- Increasing genomic complexity
- A co-evolutionary arm's race in which advances in predator "fire power" were countered by advances in victim armor - shells, spines, etc.
171
Major transitions in the history of life
Origin of life and the origin of eukaryotes
172
What came out of eukaryotes and the Cambrian explosion?
- Origin of sex
| - Origin of multicellular life - the latter has occurred multiple times
173
What brought on the origin of species?
- Social insects
| - Vertebrates
174
What brought on the origin of consciousness/self-awareness?
- Primates
- Cetaceans
- Avian dinosaurs (maybe)
175
Phylogenetic trees
Represent presumed patters of descent and are analogous to family trees
176
Nodes
Branching or terminating points
177
Internal nodes
Points of lineage splitting
178
Terminal nodes
Tips
179
Taxa
Can be species or higher taxonomic groups
180
A pair of taxa that have a common ancestor not shared by any other taxon are called _______ .
Sister taxa
181
Outgroup
Outgroup inclusion "completes the tree" by identifying character states presumed ancestral and hence the characteristics of a presumptive common ancestor
182
What is rooting the tree?
Including an outgroup
183
Phenetic relating to relatedness:
Infers relatedness from overall similarity
184
Cladistic relating to relatedness:
- Distinguishes ancestral from derived characters
| - Infers relatedness from presence of shared derived characters called synapomorphies
185
Principle of Parsimony
The most plausible phylogeny is that which necessitates
- The fewest evolutionary reversals
- Fewest independent character acquisitions
186
Evolutionary reversal
The re-acquistion of an ancestral trait or the loss of a derived trait
187
Homology
Similarity by virtue of common descent
188
T or F: The synapomorphies that define clades are homologies
True
189
Examples of homologies
Human arm, cat leg, whale fin, and bad wing all have similar homologies meaning similar structures
190
Who first discussed serial homology for the first time?
Poet J. W. von Goethe when referencing flower parts which he correctly believed were modified leaves - "foliar theory" of the flower
191
Serial homology
Duplication and modification of parts in different ways
192
Homoplasy
Similarity by independent acquisition
193
Convergent evolution
Acquisition of similar traits by distant lineages
194
Parallel evolution
Acquisition of similar traits by closely related lineages
195
Difference between convergent and parallel
- At the morphological level, vertebrate and cephalopod eyes are convergent
- At genetic level, parallel - the same regulatory genes determine their development
196
Pterodactyl, bat, and bird wings are homologous or homoplastic?
Depends on point of view
- Homologous-viewed as forelimbs - the usual view
- Homoplastic-viewed as wings -no winged common ancestor - an alternative, but equally valid view
197
Four mammalian tooth types
- Incisors
- Canines
- Premolars
- Molars
198
Carnassials
In living carnivores, P4 and M1 (certain teeth) specialized for slicing
-A synapomorphy defining order Carnivora
199
Creodonts
- Independently evolved carnassial
| - convergent evolution if reference is to which cheek teeth modified; parallel if to cheek teeth
200
Old Theory: A whale of a tale
Whales descended from extinct carnivores
201
New theory: A whale of a tale
Whales descended that whales descended from artiodactyls - "even-toed" ungulates
202
What does molecular evidence suggest about a whale of a tale?
Whales descended from artiodactyls
203
Why do morphological evidence conflict with molecular evidence for the whale of a tale?
Morphological evidence claims that whales lack double pulley astragalus (DPA)
- DPA (ankle bone) is the synapomorphy that distinguishes artiodactyls from other ungulates
- The term "double pulley" refers to the presence of two articular surfaces - one with the tibia (leg bone), the other with the os navicular (another foot bone)
204
Deriving whales from artiodactyls necessitates an evolutionary reversal: _____ .
DPA gained, then lost
205
What type of evidence suggests that primitive whales had a double pull astragalus?
Fossil evidence
206
T or F: Fossils always trump anatomy, genetics, etc. of living organisms
True
207
For a whale of a tale, _____ confirms molecular biology's take on the tale.
Paleontology
| Molecular biology says: Whales descended from artiodactyls
208
Monophyletic taxa
- Includes most recent common ancestor and ALL its descendants
- Monophyletic taxa called clades
209
Examples of monophyletic taxa
Mammals and birds
210
Paraphyletic taxa
-Includes the MRCA but not all descendants
211
Paraphyletic taxa example
Reptiles
212
Polyphyletic taxa
-Does not include MRCA, merely just certain branches
213
Example of polyphyletic taxa
Flying vertebrates - the MRCA walked
214
T or F: Branch length is arbitrary however order of tip taxa is not
False; both branch length and order of tip taxa are arbitrary
215
Characteristics of Prokaryotes
- Small; mostly unicellular
- No nucleus
- DNA organized into
- Circular chromosomes
- Plasmids - exchanged during conjugation or taken up from environment
- No mitosis
- No meiosis
- Reproduces by binary fission
- No membrane-enclosed organelles - mitochondria, chloroplasts, etc. but, bacteria do possess
- Cytoskeleton proteins
- Protein-encased organelles
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How do prokaryotes reproduce?
Not through meiosis or mitosis but through binary fission
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Example of protein-encased organelles
Carboxysomes that increase rate of photosynthesis
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What are the two prokaryotic domains?
Archaea and Bacteria
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What do the large and small subunits do together?
They collaborate to assemble proteins (translation)
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The Three Domain Theory requires that...
...observations consistent with symbiogenic origin of Eukarya is the result of lateral gene transfer
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Based on gene sequence of small ribosomal subunit Archaea and Bacteria are
Highly conserved
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What is the entry of CO2 into the Calvin cycle catalyzed by?
The RuBisCO enzyme
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Summarize the Calvin Cycle
CO2 enters which is catalyzed by the enzyme RuBisCO, extra G3P molecules are produced, these three carbon sugars are converted into glucose, plants then store glucose as starch
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What characteristics do all three domains have in common?
- Genetics (DNA)
- Metabolic (utilization of ATP)
- Structural (Ribsomes, plasma membranes, and flagella)
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Genetic similarities in all Three Domains
- DNA is the hereditary molecule
- Semi-conservative DNA replication - daughter molecules consist of one new strand; one old
- Transcription and translation: DNA -> RNA -> Proteins
- "Universal" genetic code
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Metabolic similarities in all Three Domains
- Use of high-energy compounds such as ATP
| - Production of ATP by glycolysis - anaerobic respiration
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Structural similarities in all Three Domains
Ribosomes, plasma membranes, and flagella
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Multicellular: Bacteria? Archaea? Eukarya?
Bacteria: Rarely
Archaea: No
Eukarya: Many
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T or F: all three domains have membrane enclosed organelles and sex?
False; only Eukarya has membrane enclosed organelles and sex
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Which of the three domains has circular chromosomes?
Most bacteria and all archaea
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How are Archaea similar to Bacteria?
Both....
- Unicellular
- No nuclear envelope
- Circular chromosomes
- Absence of organelles
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How are Archaea similar to Eukarya?
- Histones associates with DNA
| - Translation initiated by methionine (Met)
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What is unique about Archaea?
- Plasma membrane structure
- Cell wall composition
- Flagellar structure and development - grow from base (archaea) vs, tip (bacteria)
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What is the principal component of cell membranes?
Phospholipids
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How do the phospholipids of archaea and bacteria/eukaryotes differ?
- Archaea phospholipids are composed of branched isoprene chains bound to phosphate group by ether linkages
- Bacterial AND eukaryote phospholipids consist of straight chain fatty acids bonded by ester linkages
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What do both the archaea and bacteria/eukaryote phospholipids have in common?
The membrane is a bilayer with the hydrophobic ends on the inside
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Polarity of all phospholipids
Nonpolar inside with polar outside
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Why are prokaryotes important?
- Abundant and ubiquitous in/on bodies
- Essential to proper digestion
- Some bacteria pathogenic
- Participate in geochemical cycle (nitrogen cycle)
- Extremophiles
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Nitrification
Nitrogen fixing bacteria convert atmospheric nitrogen, N2, into compounds that can be used by terrestrial plants. Part of Nitrogen/geochemical cycles
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Denitrification
Other prokaryotes recycle ammonia (product of decay) back to N2. Part of Nitrogen/geochemical cycles
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What does it mean that some prokaryotes are extremophiles?
Some prokaryotes live in extreme environments - high temperature, acidity, salinity - that may be similar to those in which life evolved
