paleo exam 1 Flashcards
(114 cards)
1
Q
What are the major divisions of geologic time?
A
Eon, Era, Period, Epoch
2
Q
What does the Phanerozoic Eon include?
A
Paleozoic, Mesozoic, and Cenozoic eras
3
Q
What is Stratigraphy?
A
The study of rock layers (strata) and layering
4
Q
What is a Fossil?
A
Physical remains or traces of organisms preserved in rock
5
Q
What are Body Fossils?
A
Direct remains (bones, shells, plant parts)
6
Q
What are Trace Fossils?
A
Evidence of behavior (burrows, tracks, coprolites)
7
Q
What is the Archeozoic Erathem known for?
A
Earliest evidence of life, 3.2 billion years ago
8
Q
What is the time frame for the Proterozoic Erathem?
A
2.5 billion - 570 million years ago
9
Q
What notable life forms are found in the Paleozoic Erathem?
A
Invertebrate marine fossils, first fish, amphibians, reptiles
10
Q
What characterizes the Mesozoic Erathem?
A
Age of reptiles, first mammals, birds, angiosperms
11
Q
What is the primary feature of the Cenozoic Erathem?
A
Mammals dominate, abundant angiosperms
12
Q
What is essential for fossil preservation?
A
Rapid Burial
13
Q
What are examples of unaltered soft parts in fossils?
A
Insects in amber, frozen mammoths
14
Q
What are examples of unaltered hard parts in fossils?
A
Cenozoic mollusk shells
15
Q
What is Permineralization?
A
Pores filled with minerals (e.g., petrified wood)
16
Q
What does Carbonization refer to in fossil preservation?
A
Organic material reduced to a carbon film (e.g., fossil plants)
17
Q
What is Recrystallization in the context of fossils?
A
Internal structure changes (e.g., aragonitic shells)
18
Q
What does Replacement mean in fossil preservation?
A
Original material replaced by new minerals (e.g., pyritized brachiopods)
19
Q
What are Molds & Casts in paleontology?
A
Impressions left in rock
20
Q
What is the Burgess Shale known for?
A
Soft-bodied Cambrian fossils
21
Q
What are Cubichnia?
A
Resting traces (e.g., trilobite traces)
22
Q
What are Domichnia?
A
Dwelling burrows (e.g., Ophiomorpha tunnels)
23
Q
What does Fugichnia refer to?
A
Escape traces (e.g., cnidarian escape movements)
24
Q
What are Repichnia?
A
Locomotion traces (e.g., Climactichnites trails)
25
What are Paschichnia?
Grazing traces (e.g., Radulichnus)
26
What does Agrichnia refer to?
Farming traces (e.g., Paleodictyon honeycomb burrows)
27
What are Fodichnia?
Deposit feeding burrows (e.g., Planolites)
28
What factors cause differences in fossil size, shape, and preservation?
* Growth and age differences
* Variation among individuals within a population
* Postmortem breakage and distortion
* Differences between species
29
What is ontogeny?
The embryonic and post-embryonic history of an organism.
30
Why is ontogeny difficult to study in fossils?
Fossils rarely preserve complete growth sequences.
31
What is heterochrony?
Evolutionary change due to shifts in developmental timing.
32
What are the two major types of heterochrony?
* Paedomorphosis: Retention of juvenile traits into adulthood
* Peramorphosis: Extension of development beyond normal adult stages
33
What developmental parameters affect heterochrony?
* Rate of development
* Onset of development
* Offset of development
34
What are the three main fossil growth strategies?
* Accretion: Growth by adding layers (e.g., corals)
* Addition: Incremental growth of new parts
* Molting: Shedding and regrowing exoskeletons
35
What is isometric growth?
Growth where proportions remain the same (y = mx + b).
36
What is allometric growth?
Growth where different body parts grow at different rates (y = mx^n).
37
What defines a population in evolutionary terms?
A local breeding group sharing a common gene pool.
38
What is ecophenotypic variation?
Physical differences caused by environmental factors rather than genetic changes.
39
What is sexual dimorphism?
Physical differences between males and females of the same species.
40
What is an example of fossil growth series analysis?
* Triceratops Growth Stages: Skull changes throughout life
* Edmontosaurs (Hadrosauridae): Growth variations reveal insights into species diversity
41
What is taphonomy?
The study of how organisms decay and become fossils.
42
What factors can distort fossils after death?
* Sorting: Movement by water or wind
* Breakage: More common in delicate structures
* Postmortem transport: Movement that can alter fossil appearance
43
What is population variation?
Variations between individuals within the same population.
44
What is ontogenetic variation?
Variations that occur within an individual during its lifespan.
45
What is a population in biological terms?
A group of individuals capable of interbreeding, also called a local breeding population or deme.
46
What is a gene pool?
All the genes in a population.
47
How does natural selection influence species formation?
It acts on genetic variation, favoring organisms with traits that enhance survival and reproduction.
48
What is fitness in an evolutionary context?
A measure of an individual’s ability to survive and reproduce.
49
What is reproductive isolation?
The prevention of gene flow between populations, leading to speciation.
50
What is allopatric speciation?
Speciation due to geographic separation.
51
What is sympatric speciation?
Speciation occurring without geographic isolation, often due to ecological or behavioral differences.
52
What is anagenesis?
Gradual transformation of one species into another over time.
53
What is punctuated equilibrium?
The idea that species remain stable for long periods, punctuated by rapid changes.
54
What does the fossil record show about speciation?
It provides evidence of evolutionary change, showing both gradual and rapid transformations.
55
What is phyletic gradualism?
The slow, continuous accumulation of minor changes leading to new species.
56
What is systematics?
The method of classifying life into groups based on diversity and evolutionary relationships.
57
What is taxonomy?
The science of classifying organisms.
58
What is a taxon?
Any named group of organisms (e.g., species, genus).
59
What is a binomen?
A two-part scientific name consisting of a genus and species name (e.g., Homo sapiens).
60
What are the major taxonomic ranks in order?
Kingdom, Phylum, Class, Order, Family, Genus, Species.
61
What is a type specimen?
A reference specimen used to define a species.
62
What are the rules for naming species?
Genus names are capitalized and italicized, species names are italicized but not capitalized (e.g., Tyrannosaurus rex).
63
What are the three main classification methods?
Evolutionary taxonomy, numerical taxonomy (phenetics), and cladistics.
64
What is cladistics?
A classification method based on evolutionary relationships, focusing on shared derived characters (synapomorphies).
65
What is a cladogram?
A branching diagram showing evolutionary relationships between taxa.
66
What is a clade?
A group that includes an ancestor and all its descendants.
67
What is a monophyletic group?
A natural group that includes all descendants of a common ancestor.
68
What is a paraphyletic group?
An unnatural group that excludes some descendants of a common ancestor.
69
What is a polyphyletic group?
An unnatural group that includes taxa from multiple unrelated lineages.
70
What is molecular systematics?
The study of evolutionary relationships using biomolecules like DNA and proteins.
71
Why is molecular data useful for systematics?
It provides objective evidence of evolutionary relationships.
72
What does a phylogenetic tree represent?
The branching history of evolutionary lineages.
73
What is extinction?
The total disappearance of a species or higher taxon, so that it no longer exists anywhere.
74
What is the estimated percentage of species that have gone extinct?
Over 99.9% of all species that have ever lived are extinct.
75
What is the Red Queen Hypothesis?
Species must constantly adapt and evolve to survive because other competing species are also evolving.
76
What is background extinction?
The continuous, normal rate of extinction over time.
77
What is mass extinction?
A large-scale extinction event affecting many species over a short geological time.
78
What were the five major mass extinctions?
Permo-Triassic, Cretaceous-Tertiary, Late Devonian, Late Ordovician, Late Triassic.
79
Which was the largest mass extinction?
The Permo-Triassic extinction, which wiped out 96% of marine species and 75% of land vertebrate families.
80
What caused the Permo-Triassic extinction?
Possible causes include the formation of Pangaea, global cooling, and the Siberian Traps volcanic eruptions.
81
What caused the Cretaceous-Tertiary (K-T) extinction?
A possible asteroid impact (Chicxulub crater) and Deccan Traps volcanism.
82
What percentage of marine species went extinct in the Permo-Triassic event?
96% of marine species.
83
What species went extinct at the end of the Cretaceous?
Dinosaurs (except birds), pterosaurs, many marine reptiles, ammonites, and some plants.
84
What is the Lilliput Effect?
A post-extinction phenomenon where species become temporarily smaller due to environmental stress.
85
What was the cause of the Late Devonian extinction?
Possibly global cooling, black shale formation, or an impact event.
86
What was the suspected cause of the Late Triassic extinction?
Oceanic anoxia, climate changes, and possibly an asteroid impact.
87
What is the "Nuclear Winter" scenario?
A theory that asteroid impact or volcanic activity could have caused a dark period leading to plant and herbivore collapse.
88
What is periodicity in mass extinctions?
The debated idea that extinctions occur in regular cycles, possibly every 26 million years.
89
What is paleoecology?
The study of the interaction of ancient organisms with each other and their environment.
90
What are the two types of paleoecology?
Autecology: Focuses on individual organisms and their environmental relationships.
Synecology: Focuses on the ecology of entire communities.
91
What is the difference between a habitat and a niche?
Habitat: The physical environment an organism lives in.
Niche: The organism’s role in the ecosystem, including all biological and chemical interactions.
92
What are the major marine environmental zones?
-Benthic (seafloor) and pelagic (water column).
-Benthic subdivisions: Supratidal, intertidal (littoral), subtidal, bathyal, abyssal.
-pelagic subdivisions: Neritic (shallow shelf), oceanic (deep ocean).
93
What are the classifications of benthic organisms?
-Infaunal: Live within the substrate.
-Epifaunal: Live on top of the substrate.
-Sessile: Immobile.
-Vagile: Mobile.
94
How are pelagic organisms classified?
-Planktonic: Passive floaters.
-Nektonic: Active swimmers.
95
How are organisms classified by feeding strategy?
-Autotrophs: Photosynthesizers and chemosynthesizers.
-Heterotrophs: Eat other organisms or organic material.
96
How does temperature affect organisms?
Affects metabolism, growth rates, reproduction, and calcium carbonate precipitation.
97
What is the carbonate compensation depth (CCD)?
The depth (~3000-4000m) below which calcite dissolves, leaving only siliceous sediments.
98
Why is substrate important for benthic organisms?
Some organisms need hard surfaces to attach to, while others are adapted for soft or soupy sediments.
99
What is the role of substrate in fossil preservation?
Fossil assemblages can provide information about past environments if not transported.
100
What is biostratigraphy?
The use of fossils to determine the relative age of rock layers.
101
What are biostratigraphic zones?
Zones based on the first or last appearances of fossils.
102
What is a concurrent range zone?
A zone defined by the overlapping range of two or more taxa.
103
What is a lineage zone?
A zone defined by evolutionary first appearances of successive taxa.
104
What is an interval zone?
A zone defined by two successive first or last occurrences of unrelated taxa.
105
What are Lazarus taxa?
Taxa that seem to disappear during a mass extinction but reappear later.
106
What are Elvis taxa?
Taxa that resemble extinct forms but are actually new, unrelated species.
107
What is the Zombie effect?
Fossils reworked into younger strata, misleading stratigraphic records.
108
What is biogeography?
The study of the geographic distribution of organisms and how they got there.
109
What is ecological biogeography?
The study of present-day processes affecting species distribution.
110
What is historical biogeography?
The study of past distributions and processes that explain current distributions.
111
What is the role of plate tectonics in historical biogeography?
Explains species distribution through continental drift (e.g., Pangaea, Gondwanaland).
112
What are biomes?
Large-scale ecological regions controlled by climate.
113
What factors influence marine biogeographic provinces?
Latitude, temperature, and ocean circulation.
114
What is the “Noah’s Ark” phenomenon in biogeography?
When a continent carries species as it drifts and collides with another landmass.
