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front 2 Compare and contrast gradualism (uniformitarianism) and catastrophism
explanations of the history of earth. | back 2 - Catastrophism -> The hypothesis by Georges Cuvier that each
boundary between strata corresponded in time to a catastrophe that
had destroyed many of the species living there.
- Gradualism
-> A view of Earth's history that attributes profound change to
the cumulative product of slow, but continuous processes.
- Uniformitarianism -> Charles Lyell's idea that geographic
processes have no changes throughout history.\
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front 3 • How does descent with modification explain the adaptations of
organisms as well as the unity and diversity of life? | back 3 - -decent with modification simply means that organisms share
many characteristics, each coming from a common ancestor, the
diverse modifications come from each animal living in different
environments. They accumulated these modifications over
generations.
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front 4 • How are natural selection and artificial selection different? | back 4 - Artificial Selection -> Modification of a species by human
intervention so that certain desirable traits are represented in
successive generations.
- Natural Selection -> The process
in nature by which, according to Darwin's theory of evolution, only
the organisms best adapted to their environment tend to survive and
submit their genetic characteristics in increasing numbers to
succeeding generations.
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front 5 • What are Darwin's four observations/inferences about nature? | back 5 - Observation 1 - members of a population vary in inherited
traits.
- Observation 2- all species can produce more offspring
than their environment can support, and many survive to
reproduce.
- Inference 1 - individuals whose inherited traits
give them a higher probability of surviving and reproducing in a
given environment tend to leave more offspring.
- Inference 2
- the unequal ability of individuals to survive and reproduce will
lead to the accumulation of favorable traits in the population over
generations.
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front 6 • Summarize the main ideas of natural selection. What role do
individuals versus populations have in this process? | back 6 - Natural selection is a process in which individuals with
favorable inherited traits are more likely to survive and
reproduce
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front 7 • List two direct observations of evolutionary change and explain. | back 7 - Two examples provide evidence for natural selection: natural
selection in response to introduced plant species, and the evolution
of drug-resistant bacteria
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front 8 • What are homologous structures? | back 8 - Homologous structures are anatomical resemblances that
represent variations on a structural theme present in a common
ancestor
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front 9 • Explain the four types of data that are used to document
evolutionary change. | back 9 - Homology
- The fossil record
- Biogeography
- Direct observations
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front 11 • List and explain four sources of genetic variation. | back 11 - Mutation
- Translocation
- gene duplication
- Crossing over
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front 12 • Why is genetic variation important? | back 12 - Variation in heritable traits is a prerequisite for
evolution
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front 13 • List the five conditions for Hardy-Weinberg equilibrium and explain
why populations are rarely in Hardy-Weinberg equilibrium. | back 13 - No mutations
- Random mating
- No natural
selection
- Extremely large population size
- No gene
flow
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front 14 • What does the Hardy-Weinberg equation test? | back 14 - Tests whether a population is evolving or not.
- The
Hardy-Weinberg equation describes the genetic makeup we expect for a
population that is NOT evolving at a particular locus
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front 15 • Describe three ways that allele frequencies can be altered in a population. | back 15 - Natural selection
- Natural selection results in alleles
being passed to the next generation in proportions that differ
from those in the present generation.
- Genetic drift (bottleneck and founder effects) including the
four key points
- The process in which chance events cause
allelic frequencies to fluctuate unpredictably from one
generation to the next
- The bottleneck
effect is a sudden reduction in population size due to
a change in the environment
- The founder
effect occurs when a few individuals become isolated
from a larger population
- Explain gene flow
- The transfer of alleles into or out of a population due
to the movement of fertile individuals or their gametes
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front 16 • How does natural selection lead to adaptive evolution? | back 16 - Natural selection consistently selects for traits that will
allow members of a population to best adapt to their environment,
while gene flow and genetic drift can possibly decrease the
advantageous alleles
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front 17 • Explain the role of directional, disruptive, stabilizing, and
sexual selection in natural selection. | back 17 - Directional selection favors individuals at one extreme end of
the phenotypic range
- Disruptive selection favors
individuals at both extremes of the phenotypic range
-
Stabilizing selection favors intermediate variants and acts against
extreme phenotypes
- Sexual selection is natural selection
for mating
- It can result in sexual dimorphism, marked
differences between the sexes in secondary sexual
characteristics
- Intrasexual selection
is direct competition among individuals of one sex (often
males) for mates of the opposite sex
-
Intersexual selection, often called mate
choice, occurs when individuals of one sex (usually females) are
choosy in selecting their mates
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front 19 • What are the four different species concept approaches to defining
a species? | back 19 -
The biological species concept states that a
species is a group of populations whose members have the potential
to interbreed in nature and produce viable, fertile offspring; they
do not breed successfully with members of other populations
-
The morphological species concept defines a species
by structural features
-
The ecological species concept views a species in
terms of its ecological niche
- Whether two can survive in
each other’s environment.
-
The phylogenetic species concept defines a species
as the smallest group of individuals on a phylogenetic tree
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front 20 • Know the prezygotic and postzygotic reproductive barriers that
contribute to reproductive isolation. | back 20 - Prezygotic barriers block fertilization from occurring by
- Impeding different species from attempting to mate
- Preventing the successful completion of mating
-
Hindering fertilization if mating is successful
-
Habitat isolation: Two species encounter
each other rarely, or not at all, because they occupy
different habitats, even though not isolated by physical
barriers
- Temporal isolation:
Species that breed at different times of the day, different
seasons, or different years cannot mix their gametes
- Behavioral isolation: Courtship
rituals and other behaviors unique to a species are
effective barriers to mating
- Mechanical
isolation: Morphological differences can prevent
successful completion of mating
- Gametic
Isolation: Sperm of one species may not be able to
fertilize eggs of another species
- Postzygotic barriers prevent the hybrid zygote from
developing into a viable, fertile adult
- Reduced
hybrid viability
- Reduced hybrid
viability: Genes of the different parent
species may interact and impair the hybrid ’s
development or survival in its environment
- Reduced hybrid fertility
-
Reduced hybrid fertility: Even if hybrids
are vigorous, they may be sterile
- Hybrid breakdown
- Hybrid
breakdown: Some first-generation hybrids are
fertile, but when they mate with each other or with
either parent species, offspring of the next generation
are feeble or sterile
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front 21 • Explain how allopatric and sympatric speciation occur. | back 21 - In allopatric speciation, gene flow is
interrupted or reduced when a population is divided into
geographically isolated subpopulations
- For example, the
flightless cormorant of the Galápagos likely originated from a
flying species on the mainland
- sympatric
speciation occurs in populations that live in the same geographic
area. Occurs if gene flow is reduced through polyploidy, sexual
selection, and habitat differentiation
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front 22 • Explain the time course of speciation in terms of the fossil record
and rate of speciation. | back 22 Fossil records don’t show gradual changes between species they just
show a rapid change |
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front 24 • Differentiate between macroevolution and microevolution. | back 24 - Macroevolutionary changes over large time scales
- Formation of a new species
- microevolution -changes within a species; not the creation of a
new species
- Examples: resistant bacteria to antibiotics and
insects resistant to pesticides.
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front 25 • Understand what information can be found in the fossil record. | back 25 - Old layers in the fossil record would be associated with older
species
- The fossil record reveals changes in the history of
life on Earth
- The fossil record shows changes in kinds of
organisms on Earth over time
- The fossil record is biased in
favor of species that
- Existed for a long time
-
Were abundant and widespread
- Had hard parts
- Fossil record only shows sudden change not gradual
change in species.
- The fossil record is biased in favor
of species that
- Existed for a long time
- Were
abundant and widespread
- Had hard parts
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front 26 • Explain how radiometric dating is performed. | back 26 - The "absolute" ages of fossils can be determined by
radiometric dating
- radioactive “parent” isotope decays to a
“daughter” isotope at a constant rate
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front 27 • Know the hypothesis for the origin of eukaryotes through serial endosymbiosis. | back 27 - The endosymbiont theory proposes that mitochondria and
plastids (chloroplasts and related organelles) were formerly small
prokaryotes living within larger host cells
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front 28 • Understand how continental drift could explain the distribution and
diversity of life on earth. | back 28 - Continental drift has many effects on living organisms
- A continent’s climate can change as it moves north or
south
- Separation of land masses can lead to allopatric
speciation
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front 29 • What is the role of Hox genes in animal development? | back 29 - homeotic genes that determine where basic features are located,
providing positional information in an animal embryo. Changes to
these genes result in significant morphological changes. For example
two hox genes prevent limb formation in snakes.
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front 31 • How can hierarchical classification and phylogeny be linked together? | back 31 - Phylogeny is the evolutionary history of a species or group of
related species
- Systematists depict evolutionary
relationships in branching phylogenetic trees
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front 32 • Know how to "read" a phylogenetic tree. | back 32 - Phylogenetic trees show patterns of descent, not phenotypic
similarity.
- Phylogenetic trees do not indicate when species
evolved or how much change occurred in a lineage.
- It should
not be assumed that a taxon evolved from the taxon next to it.
- Shared ancestral
- Shared derived characteristics
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front 33 • Explain how phylogenies are determined. | back 33 - morphological and molecular data. To infer phylogenies,
systematists gather
- information about morphologies, genes,
and
- biochemistry of living organisms.
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front 34 • Understand the difference between analogy (convergent evolution)
and homology (shared ancestry). | back 34 - Homology is similarity as a result of shared ancestry
- Analogy is similarity due to convergent evolution.
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front 36 • What is a shared derived character? | back 36 - A shared derived character is an evolutionary novelty unique to
a particular clade. In comparison with its ancestor, an organism has
both shared and different characteristics.
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front 37 • How are maximum parsimony and maximum likelihood different? | back 37 - Maximum parsimony assumes that the tree that requires the
fewest evolutionary events (appearances of shared derived
characters) is the most likely
- The principle of maximum
likelihood states that, given certain rules about how DNA changes
over time, a tree can be found that reflects the most likely
sequence of evolutionary events
- Parsimony is the fewest
turns But since there’s construction the route is slower -so maximum
likelihood
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front 38 • What are molecular clocks and how can they be used? | back 38 - A molecular clock uses constant rates of evolution in some
genes to estimate the absolute time of evolutionary change
- similar genes or segments of DNA occur in different species and
appear to have a reliable mutation rates, they can be used as a
molecular clock
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