Exam 3 Flashcards
In what famous piece of work did Buffon suggest that life in the NewWorld was small, weak, and feeble?
Histiore Naturelle
Who opposed Buffon’s work?
Thomas Jefferson
What is the most recent mass extinction?
Pleistocene megafauna extinction
The remains or traces of past-living organisms (usually more than 10,000 years old)
Fossils
What is the term for when water seeps into fossils breaking them down but the shape of the fossil is preserved
Dissolution
What is the term for when organisms fossilize as layers of thin carbon spread on sandstone and shale
Carbonization
What kind of rock does fossilization most often occur in?
Sedimentary rock
What is the term for when huge numbers of fossils are found together?
Lagerstatten
Fossils found lower down in the sediment at a particular locality are older than those closer to the surface
Law of Superposition (relative)
Is chemical dating by testing fluorine concentration relative or absolute?
Relative
Is radiocarbon and radiopotassiunm dating relative or absolute?
Absolute
What does Carbon 14 decay into?
Nitrogen 14
What is Carbon 14’s half-life?
5730 years
What is Potassium 40’s half-life?
1.3 billion years
Lag time between last known species and extinction
Backward smearing
Burrowing animals more fossilized remained up through the layers
Forward smearing
A sudden spike in extinction.
Typically a 50%-75% loss of species in many major taxa over a broad geographical range
Mass extinction
All other extinction not considered mass extinction, making up about 95% of extinction events
Background extinction
Species native to only one area
Endemic
Rapid burst of speciation
Evolutionary radiation
What did new morphologies in herbaceous plants allow for?
More efficient light gathering, and better water absorption/transportation
What are the 5 major mass extinctions?
End of Ordovician Late Devonian Late Permian End of Triassic Cretaceous-Paleocene Boundary
Occurred ~65 MYA
Half of genera died (including dinosaurs)
Data eventually looked indicative of a catastrophic event
The Cretaceous-Paleogene Mass Extinction
Russell and Tucker proposed that what catastrophic event ended the cretaceous period?
A large supernova explosion near Earth
Walter Alvarez and his father supported the theory that what catastrophic event ended the cretaceous period?
An asteroid collision with Earth
Which element is rare and indicative of an asteroid collision?
Iridium
Amino acids of et origin, glassy materials called spinels, “impact diamonds,” and rapid extinction in pollen-producing plants and marine taxa are all proof of…
Asteroid contact with Earth
Largest mass extinction, Occurred ~250 MYA, 90% of species went extinct, the slate of life was almost wiped clean
Permian Mass Extinction
A large volcanic eruption in Siberia ~251 MYA causing an initial cooling period followed by warming, increased ocean acidification and low levels of oxygen are thought to be the cause of which mass extinction?
Permian Mass Extinction
Does species longevity have an effect on probability of extinction?
No
Does geographical range have an effect on probability of extinction?
Log-odds ratio of zero means no association, positive value indicates that species with broad ranges show reduced extinction rates
A model in which new species arise from a gradual transformation of an ancestral species through slow and constant change
Phyletic gradualism model
One way that new species in the fossil record may arise: branching speciation events
Cladogenesis
One way that new species in the fossil record may arise: gradual modification of form without branching speciation
Anagenesis
Lineage has not died out but changed so much that it is now classified as a new species
Pseudoextinction
A model in which a minor degree of change is always occurring but stasis, is the rule during the vast majority of lineage’s history
Punctuated Equilibrium Model
Caused there to be a new array of multicellular organisms with new body forms and shapes; most of the animal groups that have ever lived appeared for the first time in this era
The Cambrian Explosion
Trend in which the direction of diversification is limited due to some constraint on evolution
Passive trend
Trend in which the tendency for entire distribution to increase/decrease
Active trend
Two types of active trend
Parallel or Species Selection
When environmental unpredictability is high, is sexual or asexual reproduction high?
sexual reproduction
When the number of niches is low, is asexual or sexual reproduction high?
asexual reproduction
When parasite load is high, is asexual or sexual reproduction high?
sexual reproduction
The production of offspring from unfertilized gamete (multicellular eukaryotes)
Asexual reproduction
Unfertilized eggs are produced by mitosis-like cell division (daughter cels with an unreduced number of chromosomes); daughter cells are genetically identical to mother
Apomixis
Production of haploid gametes from meiosis which subsequently fuse to restore diploidy; daughter cells are genetically distinct from mother and siblings
Automixis
The joining together of genetic material from two parents
Sexual reproduction
Alternating phases of meiosis and gamete fusion
Amphimixis
What are the three steps of amphimixis?
Recombination, gamete production, gamete fusion
Do sexual or asexual females pass on twice as many copies of their genes?
Asexual
Who showed that the number of asexual individuals would grow at twice the rate of sexual individuals?
John Maynard Smith
Sexual reproduction by the fusion of dissimilar gametes
Anisogamy
Sexual reproduction by the fusion of similar gametes
Isogamy
Two-fold cost of sex is only seen in what type of sexual reproduction?
Anisogamy
An allele at one locus os favored when it occurs in the presence of a specific allele at another locus
Favorable gene combination
Does sex break up or favor favorable gene combinations?
Break up
Despite all of the costs, sex still does these two things that seem to be most important…
Purges deleterious alleles, and generates genetic variation, some of which can be favored by natural selection
The irreversible buildup of deleterious mutation in asexual species is referred to as…
Muller’s ratchet
Recombination allows natural selection to operate at a quicker rate
The Fisher-Muller Hypothesis
- Oscillations in the relative frequency of asexual lineages when parasites are present
- Time lags: for a brief time the asexual host may evolve defense, until selection favors parasite
- A correlation between parasite load and sexual reproduction
The Red Queen Hypothesis
Selection favors females who have a genetic predisposition to choose mates that provide them with resources-above and beyond sperm- that increase their fecundity and/or survival
Direct benefit of intersexual selection
Ofte males display elaborate ornaments and females exhibit a preference for these ornaments. Why?
Good genes
Some females express a preference for an ornament, and because of this preference, selection favors both the male ornament and further female preference for it. What does this describe ?
Fisherian Sexual Selection
When statistical associations are preset between the alleles at 2 different loci
Linkage disequilibrium
Females benefits from mating with colorful males because they are more likely to produce sons who are colorful and this preferred by females
Sexy son mechanism
If genetic correlation between trait and preference is extremely high =, the system can “run away” in a positive feedback loop
Runaway sexual selection
Females initially prefer a certain male trait, not because of any mating benefit, but rather female nervous systems respond to the trait either because it is associated with some benefit outside of mate choice or simply as an artifact of how the stimulus excited their nervous system
Sensory bias
The probability that an all in one individual has a copy that is identically decent in another individual
Coefficient of relatedness
A pair of strategies in which neither player can benefit by unilaterally changing his strategy
Nash equilibrium
