DAT Bootcamp - Evolution
_____ is the gradual development and change of heritable traits in a population over successive generations
evolution is the gradual development and change of _____ in a population over successive generations
evolution is a long process that brings about _____
what are the 5 lines of evidence for evolution?
fossils; biogeography; embryology; comparative anatomy; biochemistry
what is the study of fossils?
what are the 2 types of fossils?
actual remains; ichnofossils
ichnofossils are fossils of _____, such as footprints and nests
the process of a fleshy organism turning into solid rock is called _____
describe the process of petrification:
dead organism buried by sediment --> sediment minerals slowly replace organic body matter
_____ explains the spread of different species throughout the world
_____ separated into 7 different continents, causing evolution
embryological similarities are observed during the development stage in related organisms, which provides evidence for _____
_____ compares different body parts from different animals to see possible connections between them
comparative anatomy gives evidence for _____
may or may not
perform the same function, but they are derived from a common ancestor
what is an example of homologous structures?
the forearm of a bird and the forearm of a human
_____ structures have the same function, but they are not derived from a common ancestor
what are some examples of analogous structures?
shark v. penguin v. dolpfin
_____ structures do not serve a purpose
what are some examples of vestigial structures?
ostrich wings (cant fly), or the human appendix (can't digest cellulose like cows)
biochemical evidence of evolution comes from the comparison of conserved _____ & _____ in related species
DNA regions; metabolic pathways
name 3 important scientists that contributed to the theory of evolution:
Cuvier; Lamark; Darwin
Cuvier was the founder of _____
Cuvier proposed _____ as his evolutionary hypothesis, based on his observation of _____
catastrophism; fossil layers
_____ says that sudden catastrophes caused mass extinctions, leading to landscape changes and evolutionary changes
which 2 hypothesis did Lamarck propose for his belief of evolution?
the use/disuse hypothesis, and the inheritance of acquired traits hypothesis
describe Lamark's hypotheses, as well as how they fit together:
structures that are used will develop and pass to subsequent generations
(not true - aquired traits are not heritable)
are Lamark's hypotheses true?
no - environmentally acquired characteristics are not heritable from generation to generation
Darwin proposed the theory of _____
is the theory of natural selection true?
does the theory of natural selection add support to the theory of evolution?
what is the main thing that evolution refers to?
heritable changes in allele frequencies in populations over time
_____ is the
process where alleles become more or less common as a result of the individual's interaction with the environment
natural selection is the
process where _____ become more or less common as a result of the individual's interaction with the _____
genetic variations that lead to different traits in organisms are _____, but natural selection is _____
(individuals/populations) evolve over the course of generations
_____ describes an organism's ability to survive and produce viable and fertile offsprings
describe the general conditions for increasing an organism's fitness:
reproducing more viable and fertile offspring
what are the 4 requirements for natural selection to occur?
the demand for a resource must exceed its supply
there must be fitness differences between traits
traits must be heritable
the different traits in question must be significant to reproduction/survival
natural selection occurs on the basis that there is always an _____ supply to the growing demand, which leads to competition
natural selection occurs on the basis that there is a difference in the ability of _____ to affect _____
heritable traits; fitness
natural selection occurs on the basis that traits must be _____
natural selection occurs on the basis that trait variations are significant to _____ or _____
(would not affect fitness otherwise)
what are the 3 different types of natural selection?
stabilizing; directional; disruptive
in stabilizing selection, the _____ trait is favored
what is an example of stabilizing selection?
(babies are roughly the same general weight)
in _____ selection, one extreme is favored
what is an example of directional selection for bacteria?
in _____ selection, rare traits (oddballs) are favored over mainstream ones
(this is the opposite to stabilizing selection)
_____ occurs when there is
mating between male and female
females boost the _____ of their offspring because they _____ of energy to mating
quality; devote a lot
males boost the _____ of their offspring because they _____ of energy to mating
quantity; do not devote a lot
why is/isn't sexual selection a type of natural selection?
sexual selection is a special case of natural selection because the traits that make for a more attractive mate could also signal predators
artificial selection is not a type of _____ selection
artificial selection is usually carried out by humans when they breed for favorable traits - what are some examples?
dog breeds and agriculture
allele frequency is the same as _____ frequency
_____ describes how often you can find a gene variant
_____ refers to the process when gene frequencies change within a population (from generation to generation)
describe gene equilibrium:
there is no change in gene frequencies, meaning there is no evolution
what are the 2 Hardy-Weinberg formulae?
p + q = 1
p² + 2pq + q² = 1
what happens if only 1 of 2 Hardy-Weinberg equations holds true?
the population is not in Hardy-Weinberg equilibrium
what are the requirements for Hardy-Weinberg equilibrium?
andom mating; no *M*utation; no *N*atural selection; no
arge populations; *R*andom mating; no *M*utation; no *N*atural selection; no
(where & = N)
Hardy-Weinberg equilibrium _____ occurs in the real world
large populations minimize the effects of _____
(large populations are a requirement for Hardy-Weinberg equilibrium)
genetic drift is the random increase/decrease in _____
the founder effect is a special type of _____
the _____ occurs when a group of emigrating individuals do not reflect the allele frequencies of the original population
_____ describes the phenomena where individuals do not seek a particular type of individual to mate with
(condition for Hardy-Weinberg equilibrium)
individuals that mate randomly do not mate only with _____ individuals or express _____ selection
random mating decreases the chances of a specific allele changing in frequency, so it is a condition for _____
there cannot be any mutations to introduce new alleles in the population in order for _____ to occur
in Hardy-Weinberg equilibrium, the environment is not impacting the allele frequencies, and all traits are neutral - in other words, no _____ occurs
migration _____ occur in Hardy-Weinberg equilibrium
(no gene flow - aka the population must be isolated)
what are the 4 sources of genetic variation?
mutation; sexual reproduction; balanced polymorphism; polyploidy
_____ is the most straightforward way to develop a new allele (genetic variation)
what are the 3 ways sexual reproduction creates genetic diversity?
crossing over; independent assortment; random joining of gametes
what is a balanced polymorphism?
the maintenance of different phenotypes in a population
what are the ways to maintain a balanced polymorphism?
heterozygote advantage; minority advantage; hybrid advantage; neutral variations
how do certain heterozygous individuals create balanced polymorphisms?
they could be more fitted to the environment than homozygotes
give a common example of a heterozygote advantage, which leads to a balanced polymorphism:
African sickle cell
note that sickle cell carriers do not have sickle cell anemia
how do certain minority groups create balanced polymorphisms?
their rare phenotypes could offer higher fitness than the more common phenotypes
describe the mechanism of the minority advantage:
rare allele has high fitness --> rare allele becomes more common --> "rare" allele is no longer rare or advantageous --> evolution to new rare allele
minority phenotypes cycle between low and high _____ to balance a polymorphism
a _____ is a result of breeding between 2 different strains of organisms
_____ are usually superior to the species that made them, due to their combination of different genes
(hence, hybrid advantages lead to balanced polymorphisms)
hybrids can create balanced polymorphisms because the species that make them are given more _____, which leads to more _____
breeding options; variety
what type of variations do not cause any benefit or harm to the organism?
_____ can create balanced polymorphisms because there is not selective advantage/disadvantage; there is only increased variety
what are some benefits of diploidy?
2 copies of each chromosome = 2 copies of each trait (maintain variety + protect against mutation)
dominant > recessive alleles (maintain variety + protect against certain diseases)
_____ contain multiple copies of chromosomes, and multiple alleles for each gene
polyploids have a high _____ of traits, which leads to the maintenance of more _____ in the genome
(never know when those traits/alleles may become favorable in the environment)
what are the 5 key factors that lead to microevolution?
genetic drift; non-random mating; mutations; natural selection; gene flow
_____ is a
in the allele frequencies of a gene pool
what size population is most affected by genetic drift?
(large populations tend to be protected from genetic drift)
the _____ occurs when there is a disaster that kills off most of the population, leaving only a handful of alleles
the bottleneck effect is a type of _____
describe the founder effect:
a small portion of a population migrates to a new location, altering the allele frequency of the ensuing population in that new location
the founder effect is a type of _____
_____ describes the process where individuals with a low relatedness end up breeding
_____ describes the process where highly related individuals breed with each other
is involved with _____, traits are selected for based on how they confer fitness within an ecosystem
_____ is the process of moving alleles between populations through migration
gene flow causes alleles to _____ and eventually make variations between populations _____
_____ describes allele changes at the species level, or higher
genes can change within 1 generation in _____, but evolution takes time in _____
species are individuals that can _____
different species are _____ separated (gene pool isolation)
what are the 2 mechanisms for reproductive isolation?
_____ isolation prevents fertilization, even if mating is attempted between 2 different species
prezygotic isolation prevents the formation of a _____
what are the 5 main types of prezygotic isolation?
habitat; temporal; behavioral; mechanical; gamete
habitat isolation is a _____ mechanism, where mating is hindered between 2 species that occupy different habitats
_____ is a prezygotic isolation mechanism, where 2 species breed and reproduce at different times/seasons
behavioral isolation is prezygotic isolation mechanism, where 2 species do not _____ for each other
perform the correct courtship rituals
mechanical isolation is a prezygotic isolation mechanism, where _____ between different species
male and female genitalia are not compatible
gamete isolation is a _____ mechanism, which occurs when gametes cannot recognize and fertilize each other
the zona pellucida is a form of _____ for humans
prezygotic gamete isolation
_____ isolation is the backup in case a hybrid zygote forms
what are the 3 main mechanisms for postzygotic isolation?
hybrid mortality; hybrid sterility; hybrid F2 breakdown
hybrid mortality is a postzygotic isolation mechanism where the hybrid zygote is _____, so it _____ before reaching reproductive age
not viable; dies
why does hybrid mortality occur?
different species tend to have a different number of chromosomes, which do not pair correctly
describe the postzygotic isolation mechanism of hybrid sterility:
a hybrid zygote survives to reproductive age, but it cannot reproduce
what is the most common example of a sterile hybrid?
even if hybrids could reproduce, their offspring would suffer from decreased fitness - this is a postzygotic isolation mechanism known as _____
hybrid F2 breakdown
what is speciation?
the process that describes how species actually form
what is the first and most important step of speciation?
describe the mechanism of reproductive isolation as it relates to speciation:
interruption of gene flow between populations --> separation where alleles cannot cross between populations --> new species
what are the 2 modes of speciation?
allopatric speciation occurs due to the presence of a _____ that stops populations from breeding
adaptive radiation is a type of _____
in adaptive radiation, many new species arise from a single ancestor - why?
populations adapt to their niches differently
what is a famous example of adaptive radiation?
_____ occurs without the presence of geographical barrier
what are the 3 ways to achieve sympatric speciation?
balanced polymorphism; polyploidy; hybridization
what are the 2 main theories of macroevolution
phyletic gradualism; punctuated equilibrium
_____ says that evolution happened gradually, with the accumulation of many small intermediate changes
phyletic gradualism is not likely to be true - why?
we cannot see intermediary changes in the fossil record
_____ says that there are short spurs of evolutionary changes during long periods of stasis (no evolution)
punctuated equilibrium is more likely to be true than phyletic gradualism - why?
it is more supported by the fossil record
what are 4 patterns of evolution?
divergent; convergent; parallel; coevolution
_____ evolution occurs when species diverge from a common ancestor (i.e., the species went through different changes)
_____ evolution describes the process where 2 completely unrelated species grow more and more alike, due to adaptations in similar environments
convergent evolution tends to give rise to _____ structures
describe the process of parallel evolution:
when 2 related species diverge off from a common ancestor, but they both went through similar changes
coevolution occurs when 2 species impart _____ on each other, resulting in the evolution of _____
selective pressures; both species
what are some conceptual examples of coevolution?
camouflage; aposematic coloration; mimicry
_____ allows animals to avoid visual detection through matching their appearance to the environment
camouflage (cryptic coloration)
describe aposematic coloration (warning coloration):
a bright and vibrant coloration that warns predators about poison
_____ occurs when 1 species evolves to resemble another species
what are the 2 types of mimicry?
batesian mimicry occurs when when a _____ species mimics the coloring of a _____ species
_____ mimicry occurs when different poisonous species that share a common predator evolve to resemble each other
branch diagrams that show the
evolutionary relationships between different taxa are known as _____
a _____ includes an ancestor and all descendants from that ancestor
could a clade be as large as the entire phylogenetic tree?
yes - clades include a common ancestor and all the descendants from that ancestor
the phylogenetic tree with the least number of assumptions is preferred because it minimizes _____
homoplasy (convergent evolution)
homoplasy is also called _____ evolution
homoplasy describes when two distinct clades develop _____ structures
(homoplasy = convergent evolution)
a phylogenetic tree with the least number of evolutionary reversals or convergent/parallel evolutions is the simplest and therefore the best - what is this known as?
when did the Big Bang give rise to the Universe?
14 billion years ago
when was the Earth created?
4.5 billion years ago
the Earth is _____ as old as the Universe
when did the first prokaryotes arise?
3.5 billion years ago
when did eukaryotes arise?
2 billion year ago
what are the components of the modern Earth's atmosphere (in order of abundance)?
nitrogen (78%); oxygen (21%); argon (0.9%)
trace amounts of CO2, CH4, and O3
what are the main components of the modern Earth's crust (ranked by % weight)?
oxygen (47%); silicon (28%); aluminum (8%)
what as earth primordial atmosphere made of?
compounds, except for oxygen
the primordial atmosphere was a _____ environment without oxygen
what happened as the gases in the primordial atmosphere began to cool down?
a primordial sea developed
what did the primordial sea contain (primarily)?
H2O, and minerals found in the Earth's crust
what were the first organic compounds?
acetic acid, amino acids, and formaldehydes
why is it important that the early Earth environment was a reducing environment (i.e., that it did not contain oxygen)?
organic compounds could not have formed otherwise
which scientists developed the Organic "Soup" Theory
Oparin & Haldane
the Organic "Soup" Theory shows support for the benefits of an early _____
which scientists supported the Organic "Soup" Theory?
Miller & Urey --> Miller-Urey experiment
what were the most important factors that lead to the development of organic compounds in the Earth's early atmosphere?
reducing environment (oxygen is too reactive to have allowed chemicals to form); lightning; volcanic heat; UV radiation
a _____ is someone who looks and behaves like a human
a _____ is something that looks and behaves like a protein
simple _____ of the early Earth gradually became proteinoids
proteinoids are _____ produced proteins
what happened after proteinoids were formed in the early Earth?
_____ are biological prototypes because they had microsomes and proteinoids
(basically cell precursors)
_____ are membrane like substances
what formed after protobionts arose in the early Earth?
heterotrophic prokaryotes formed
heterotrophic prokaryotes obtained their energy by _____
consuming surrounding organic materials
what happened after heterotrophic prokaryotes formed?
they evolved into autotrophic prokaryotes
autotrophic organisms have the ability to _____
make their own food
cyanobacteria are photosynthetic, autotrophic prokaryotes - why is this important?
they (and organisms like them) introduced oxygen into the atmosphere
what happened after autotrophic prokaryotes formed?
oxygen accumulated, terminating abiotic chemical evolution
with the introduction of oxygen, the earth transformed from what to what?
a reducing environment to an oxidizing environment
what ended abiotic chemical evolution?
what important molecule was introduced by autotrophs?
how did the ozone layer form?
oxygen reacted with incoming UV rays
_____ was probably the biggest source of energy for propelling the abiotic formation of organic compounds
what is the significance of the ozone layer?
it cut the supply of UV radiation short, forcing abiotic chemical evolution to terminate (added to the effects of oxygen alone)
what happened after oxygen accumulated and abiotic chemical evolution terminated?
primitive eukaryotes formed
the _____ theory suggests that some membrane-bound organelles (mitochondria/chloroplasts) were free-living prokaryotes that were engulfed by other cells
the endosymbiotic theory suggests that some _____ were free-living prokaryotes that were engulfed by other cells
membrane-bound organelles (mitochondria/chloroplasts)
the endosymbiotic theory suggests that some membrane-bound organelles (mitochondria/chloroplasts) were actually once free-living _____, which were engulfed by other prokaryotes by _____
what evidence is there to support the endosymbiotic theory?
mitochondria/chloroplasts have their own unbound DNA and divide by binary fission; thylakoid membranes resemble cyanobacteria membranes
what happened after primitive eukaryotes formed?
more complex eukaryotes and multicellular organisms came about
the _____ tried to mimic the primordial Earth environment to test out the Organic "Soup" Theory
(it confirmed the Organic "Soup" Theory)