Evolution Final Flashcards
what is biological evolution
phenotypic change in a population or in a species at a multi generational basis
what is geological evolution
chemical or physical attributes of the earth changing over time
what are the time units in general for evolution
generally decades and centuries
what are the levels of phenotype
biochemical, cellular, morphological, physiological, behavioral characteristics
what a biochemical phenotype
ex. proteins, blood type
why are behavioral characteristics phenotypic
can be programmed genetically making it phenotypic
what does it mean for something to be heritable
parent passing genetic information to offspring
what are novel alleles
alleles that can manifest within a population
whats an example of genetic material undergoing change
novel alleles
whats an example where having dominant genes is bad
huntingtons disease
what are the dominance types
dominant, codominant, incomplete dominance
what are the modes of genetic expression
mendelian or non mendelian
what are the reproductive modes
sexual vs asexual
what level does biological evolution work at
population and species level
what is the defination of evolution at the biological level
change in genetic makeup over time
changes in allele abundance in a population over time does what
causes biological evolution
what is biological success
ability to survive and produce reproductive offspring
what was the evolutionary view in the 18th century
species were immutable (biblical creation unable to change)
what was overlooked to uphold the idea of immutable species
individual variation
what physical evidence exists to support evolution
fossils
what are the two types of evidence to support evolution
physical and circumstantial
what is circumstantial evidence
information that is consistent with the overall process (something that can be assumed)
what is physical evidence
information that directly indicates changes in living organisms
what is the cosmic perspective
hypothesis on the way the earth was created (big bang->nebular hypothesis->origin of earth)
what did the big bang create and how long ago was it
14bya created universe
when and how was the solar system created
4.6bya by the nebular hypothesis
how long does it take to form a star
about 1 million years
what is the nebular hypothesis
gravitational attraction gas and dust particles
how long ago was the earth formed
4.5bya
what is the orientation of plants
planets form an acceleration disk associated with a rotating star, matter gravitationally attracts creating larger bodies with higher gravitational fields
what did compression of matter do to the earth
cause it to heat up
how many eons is earth history broken into
4
what is the first eon of earth history
haldean
what was haldean atmosphere like
very rich in carbon dioxide, with water vapour, ammonia, and methane
what helped decrease atmospheric pressure of earth in haldean eon
venting of gasses into space
what was the surface of earth in haldean like
very hot surface(but was cooling), volcanism, massive precipitation
how hot was the surface of earth in haldean
230C
what are the 4 eons of earth
haldean, archean, proterozoic, phanerozoic
what arose from the proterozoic eon of earth
eukaryotic life and diversification of cells
when was life first found on earth
late haldean
when did vertebrates appear
end of proterozoic, beginning of phanerozoic
when did oxygen peak in earth history
carboniferious
what are some events that allowed for life to proliferate
more oxygen, change in ocean circulation/chemistry
how did continental drift influence life
moving continents changed climate and moved species
how did climate change affect life
dry vs wet periods, hot vs cold, rising vs falling sea level
how was co2 in the atmosphere removed
by precipitation because it dissolves in water
who was one of the first to propose a model for evolution
rene lamark-not darwin
whats an example of circumstantial evolution
similaries in limb structure
what study did carroll and boyd do
soapberry bug study
what was in short the soapberry bug study
soapberry bugs fed on balloon fruit that had a thick skin, balloon vines removed, bug started eating the golden rain tree fruit, fruit was thinner so proboscis got shorter because it was better adapted for that fruit. insects that still have balloon vine have long, those who have golden rain have short
what is the soapberry bug an example of
physical evidence towards evolution
what are some other examples of physical evidence for evolution
antibiotic resistance in bacteria, rise in pesticide resistance in dipterans
what is the role of fossils
gives evidence of past life on earth
how can original chemical components be lost in fossilized bone or tissue
mineralization
why is it better to have newer fossils
more likely to be able to extract DNA
how are fossils and rocks dated?
by layering of rock strata or by radioisotopes
what can layers of rock strata tell you
relative age of sedimentation and weather
how do radioisotopes work
nuclear decay of isotopes (looking at their half life)
what are the 3 eras of the phanerozoic eon
paleozoic, mesozoic, cenozoic
how are periods divided within eras
around every 30-80million years
which eras have epochs
cenozoic and mesozoic
when are we currently living
Eon: phanerozoic
era: cenozoic
period: quaternary
epoch: holocene
who first emphasized the idea of extinction
georges cuvier
what did william clift do
law of succession (illustrator)
what is the law of succession
graded transition
what is punctuated equilibrium
rapid change (jumps) in evolution where you may not find intermediates
what is an evidence for circumstantial evidence
vestigial organs
what are examples of vestigial organs
human coccyx and human arrector pili
what is homology
featured in different species have the same developmental source
what is the purpose of phylogeny
shows degree of relationness
what is an example of homology
different arm components used for different functions (mammal: dolphin, bat, human)
what is adaptation
a population or species becomes better able to cope with its environment
what is speciation
new species arises from a preexisting species
what drives sexual selection
female choice
what is natural selection linked with
adaptation and extinction
how do you evaluate changes in a population
hardy weinberg equation for population dynamics
how can environmental induction cause evolution
phenotype changed after conception can be heritable (ex. tanning)
what is amonomorphic gene
one allelic type for a gene
what is polymorphic gene what is polymorphic gene
at least 2 allele variances for a gene, the frequency of those alleles can be very different
when can a mispair of nucleotides cause heritable changes
if mispairing happens in reproductive cells
what is altered when you change nucleotides
the codon message leading to phenotypic changes
how can a nucleotide change alter heritable phenotype
if the nucleotides are changed in reproductive cells (somatic cells dont matter for heritability)
what kind of substitution happens when a codon is changed
replacement substitution
where was a replacement substitution first noted
in sickle cell anemia (val for glu)
what are two casual ways for nucleotide changes to occur
replication errors, damaged sites
what are some ways for a nucleotide to be damaged
chemical mutagens and radiation
what are the types of changes happening when a nucleotide changes a codon
transition or transversion
what nucleotides are changed in transition
purine for purine or pyrimidine for pyrimidine (AG or TC)
what nucleotides are changed in transversion
purine for pyrimidine (ACT or GCT)
what type of nucleotide change is more common
transition is more common than transversion
why is transversion less common than transition
transversion is easier to detect in proofreading ebcause it causes a conformational change to the DNA
which group has higher point mutation rates
sexually reproducing organisms have higher point mutation rates
the number of new alleles per individual should match the ____
mutation rate
what is the human mutation rate
1.6 per person (0.8 for sperm + 0.8 for egg)
machinery of DNA replication and repair are encoded by what
all are gene encoded proteins
what are the impacts of mutation to a species
mutations can be detrimental, but mutations are the source of individual variation
why can slight allelic variation help a population
can help population overcome change in environment so they can thrive
if you have a high mutation rate, what is your survival rate
low
how do new genes evolve
genes take on new functions and are evolved
how are new genes formed
gene duplication and unequal crossover
how does unequal crossover of genes work
loss of genes for one chromosome and gaining for the other chromosome (chromosomal alteration)
what is a chromosomal alteration
change in the morphology of chromosomes
what are some consequences of chromosomal alteration
affect gene order and organization, produces duplication and deletions, inversions, polyploidy
what is a chromosomal inversion
break occurs in the chromosome and it flips and reanneals (chromosome attachment can get mixed up)
what is the nickname for genes that have been inverted
supergenes
what is polyploidy
change in number of chromosomes per set
what is polyploidy most common in
plants not animals ( thought it can happen in animals)
what are some animal examples of polyploidy
salamanders, frogs
when is viability in polyploidy low
when polyploid is crossed with normal ploidy
what is a consequence of polyploidy
can cause reproductive isolation
how can you assess genetic diversity
direct measurement of allelic and genotype frequency
what is a direct method for measuring geneti diversity
gel electrophoresis
what does genetic diversity allow for
evolution allows a change in allelic frequency over time
what percent of loci are polymorphic in a population
33-50%
what percent of loci in an individual are heterozygous
4-15%
is allelic variance more neutralist or selectrionist
neutralist
who had a big impact on Darwin as far as natural selection
Thomas Malthus
when was there interest in population dynamics
late 18th century, early 19th
what did malthus hypothesize
populations cannot maintain exponential growth indefinitely due to insufficient resources (geometric increase)
what are the three ideals made by Malthus
geometric increase, resource limitation, intrinsic regulatory mechanisms on population growth and size
the power of population is ___ than the power of earth to produce subsistence for man
greater
subsistence increases in what kind of manner
arithmetical
populations are held within resource limits by what
death rate an birth rate
what scientist came up with the same idea as Darwin on natural selection
Ernst Mayr
what did Mayr contribute to the idea of evolution
multigenerational perspecitive, genetic diversity, importance of environmental interactions
what is differential survival
survival based on different characteristics
what is something darwin underestimated in his evolution theory
the speed at which evolution occurs
what is intraspecific
within a population
what is interspecific
population interacting with environment or other populations
what is a population
group of individduals of the same species that interacts with one another in a given area
what are the three important characteristics for a population
number of individuals, density, biomass, age distribution, growth rate, distribution, genetic makeup
how do two populations interact with each other
competition, predatory prey interactions, symbiosis
what is natality
all reproductive means (asexual vs sexual)
what factors cause change in abundance
loss and gain
what is exponential growth
continuous population growth in an unlimited environment (assumes a perfect or unlimited environment)
what is the equation for exponential growth
dN/dt=rmaxN
how do you calculate the size of an exponentially growing population at any point in time
Nt=Noermaxt
how do you calculate the standing number in a population at any point in time
Nt=BT+IT-DT-ET
how do you calculate the number expected at a future time interval
deltaN=B+I-D-E
organisms that reproduce fast have a fast ___
genetic turnover
what is heroparous
reproduce multiple times in lifetime
what is semelparous
reproduce once then die
what can you have discrete population growth
non-overlapping genetations
what is the name of the figure for discrete population growth
stair stepping cycle
what is logistic population growth
limits in resources cause limits in population size (intraspecific factors)
what is the shape of the logistic population growth graph
sigmoid shaped
what factor is dealt with in logistic population growth
fudge factor
what is the logistic population growth equation
dN/dt=rmaxN((K-N)/K)
what is the key point of the logistic population growth equation
allows for changes in r
what is k
carrying capacity
what are the ideals of robert may
stoichastity between genetations, not everything has same reproducive output, not everything same same lifespan
what did PF Verhulst do
limitations on population growth, fixed resources, logistic growth equation
what did pearl study
extended verhulsts work in population genetics
what does the k value represent
stable number of individuals that can exist in an environment (carrying capacity)
birth and death rates are not always directly related with ___
population density
when will you have the best r value
moderate density
what are the consequences of interspecific interactions
mutualism, partism/predation, interspecific competition
what growth model does intraspecific competition follow
logistic growth model
when does competition between species occur
when there is a sharing of a resource that limits growth, survival, or reproduction of each species
what are examples of resources
food, water, light, space
who did competitive exclusion experiments
Gause
what was gause’s study on
3 species of paramecium, populations stable K when grown alone, when paired some species went extinct
3 species of paramecium, populations stable K when grown alone, when paired some species went extinct
p. aurelia has more efficient feeding
what is the competitive exclusion principle
two species that use a limiting resource in the same way cannot coexist
what is resource partitioning
species using a limited resource in a different way
what kind of competition is inveigled with resource partitioning
interspecific
what are the two niche types
fundamental versus realized
what did connell look at
niche factors (distribution, survival, reproduction) of barnacles in scotland
what did peter and rosemary grant do
looked at competition in galapagos finches (beak size based on seed size)
what elements of competition are shown in the finch study done by Grant
interspecific competition, resource patitioning
what is a way to look at predator-prey relations
lotka-volterra models
what is the lotka volterra model equation
(dN)/(dt)=(rN)-(aNP)
N=number prey, P=number predators, r=population growth rate, a=capture efficiency
what is aNP
overall rate of prey removal
what happens when P=0
prey population grows exponentially
what is the equation for exploitation and population cycle
(dP/dt)=baNP-mP
m=mortality rate
b=efficiency with which prey are converted to predator offspring
what can prey do to avoid predation
behavioral or biochemical changes
what can predators do to gain prey
try to counteract prey advantages
what is the predatory arms race
prey and predators fighting to have the better advantage
what did Huffaker do
mite study with oranges and rubber balls (population cycles)
what contribution did Wallace have on Darwin
he stressed mutability of species
what evidence did darwin use for natural selection
artificial selection and natural examples of adaptations among species
what are darwins postulates
variable individuals, variation due to parents, survival of it fittest, reproduction of the fittest
whats a major example documenting darwins postulates
medium ground finches show phenotypic change over time that had no human intervention. phenotypic change was result of drought causing seeds to change in size
what did ernst mayr look at
vertebrate evolution
what did thomas huxley do
degree of gradualism, genetic inheritance and expression
who does natural selection act upon
individuals in the population
what does natural selection act upon
phenotype
is natural selection goal oriented (focusing on complexity or intelligence)
no
is natural selection predictable
yes
how is natural selection predictable
improved populations ability to deal with environment
what are the types of selection that have a favoured condition
stabilizing, directional, disruptive
what is stabilizing selection
intermediate phenotype has greatest fitness level
what is directional selection
change in env where previously less fit phenotype now has highest fitness level
what is disruptive selection
two or more phenotypes show equally high fitness levels so that polymorphism is supported in the population
what does the hardy weinberg equation predict
stability, models expected changes in a population over time
what does the hardy weinberg equation assume
no mutation, random mating, no genetic drift, no natural selection, NO EVOLUTION
what is the allele frequency equation
p+q=1
p+q+r=1
what is the genotype frequency equation
p2+2pq+q2=1 for diploid (change powers if other ploidy)
what is fitness (w)
contribution of each phenotype to the genetic makeup of the next generation
what is the highest fitness number
1.0
when would an organism have a fitness of 0
if they have lethal alleles that cause death
what is the best selection coefficient you can have (s)
0
how do you integrate fitness into hardy weinberg?
by using selection coefficient (sort of the reciprocal of fitness)
whats the selection coefficient of a highly fit organism
0
why can you not get rid of a recessive allele by natural selection alone
heterozygosity
what is the fitness of non-mendelian codominance
Aa=1-hs
AA=1
aa=1-s
does phenotypic plasticity exist
allele expression sensitivity to the environment may shape fitness
is natural selection equally operative throughout the environment
spatial differences, temporal differences
what is the model prediction for a stable population
frequency values for genotypes multipied by average population size to predict number of individuals for each genotype
what is the model prediction for a growing population
if s is low and growth is fast then number of individuals with disadvantaged phenotypes may increase
what is the model prediction for a declining population
absolute number decline for all phenotypes if r is sufficiently negative
what are the two types of selection directed towards heterozygotes
overdominance and underdominance
what is overdominance
w=1 s=0 heterozygotes favoured over dominant or recessive individuals
what is underdominance
w<1 s>0 heterozygote inferiority
what happens to alleles in overdominance
no extinction since heterozygotes favoured
what happens to alleles in underdominance
chance events can cause allelic extinction
what is frequency dependent selection
selection coefficient changes as a function of genotype frequency
what are the types of frequency dependent selection
negative or positive
what is negative frequency dependent selection
more rare phenotype in population is favoured
what is positive frequency dependent selection
more abundant phenotype is favoured
what was the example given in class on frequency dependent selection
elderflower orchid
what is the source of new alleles
mutation
introduction of new allele copies yield changes in _____
allele frequency
assume ___ mutation per 10,000 copies of a normal allele
1
what does migration allow for
movement of alleles to different populations
what example was used in class for allele migration
lake erie water snakes
what changed between two populations of lake erie water snakes
their colour morphs (melanistic vs not)
why is one colour morph in lake erie water snakes favoured over the other
predation, blending into setting, rocky versus sandy shore
what are random components of evolution
mutation, environmental changes, migration, random genetic drift
what is a process that changes evolution randomly
random genetic drift
what are key factors to the random genetic drift
chance events, population size, opportunity for inbreeding
what does longterm genetic drift lead to
reduced genetic diversity
is the success of alleles over time related to their survival value (fitness)
no
what is an example of allelic segregation
meiosis producing ova and sperm
what is sampling error
source of change in a population
random genetic drift can lead to
reduction in variabiity in a population
what makes genetic drift most likely
small population
are individuals subject to natural selection in the bottleneck effect
no
what is bottle neck effect
major reduction in survival (due to env seq causing large number indv die off)
what does bottleneck effect lead to
change in allelic abundances
what is the founder effect a reduction of
genetic diversity
what is the founder effect
formation of a new geologic population
what is jump dispersal
indv displaces from main pop over a long distance (often islands)
what is the founder effect driven by
chance dynamics
what is founder effect driven by
normal dynamics of dispersal
what is vigility
ability to cover long distances
what organisms most use jump dispersal
those with vigility (flying animals)
what are chance dynamics
outcome isnt fixed with any specific group
what are two mitigating factors
chance dynamics and colonization
what is colonization
allelic representation isnt representative of main population
what are reproductive encounters driven by
proximity and population size
whats the formula for any individual in a randomly mating population
F=1/(2N)
how can you increase the decline in heterozygosity
by having a smaller population
what can disrupt a decline in heterozygosity
migration
what was sonya cleggs work on
microsatellite DNA in silvereye birds
what is microsatellite DNA
highly repetitive non coding DNA
when would you use microsatellite DNA
systematic studies
TA TATA TATATA TATATATA TATATATATA TATATATATATA
mono nucleotide repeat di tri tetra penta minisatellite DNA
what disease deals with microsatellite DNA
huntingtons disease
huntingtons disease
australia and new zealand
what effect is seen in cleggs silvereye work
founder effect and genetic drift
what are the long term outcomes of random genetic drift
alleles drift toward fixation or loss, there is a loss of H, these outcomes assume no NS migration mutation
what is another name for sexual selection
assortative mating
what is mate choice based on in sexual selection
phenotypic features (visual, olfactory, auditory)
who initially recognized sexual selection
charles darwin
what is the more common directionality in sexual selection
female choice for males
sexual selection has parallel dynamics to what
natural selection
what is one critical dynamic in sexual selection
parental investment
what is parental investment
both sexes have an investment in their offspring
what is the genetic contribution in sexual selection
generally equal between sexes
what is the energetic contribution in sexual selection
much greater on the part of the female
ova, hatching, after care
a females reproductive success is tightly tied to what
the fitness of her mate (time and energy cost)
what are the 4 match schemes
monogamous, polygyny, polyandry, promiscuity
what is monogramy
one mate per individual with common joint care
what is polygyny
male mates with many females
what is polyandry
female mates with multiple males with male caring for offspring
what is promiscuity
multiple mates in one season for both sexes with no care being common
where is monogamy most common
birds and some fish and a few mammals
what is a group of females that a male may guard
harem
what is sexual dimorphism
phenotypic differences between sexes
what are the two types of sexual dimorphism
attractiveness and territorial defense
what are examples of attractiveness in sexual dimorphism
colouration, adornment, vocalization, courtship behaviors
what are examples of territorial defense in sexual dimorphism
size, strength, speed
what does the handicap principle counterbalance with
natural selection
whats is the handicap principle
excessive energetic cost and diminished defense
why does territoriality happen in intrasexual selection
males are territorial over females or a habitat so females can be well nested
where is polygyny territoriality popular
in lizards and mammals
size strength intelligence
what are the formats for intrasexual selection
sperm competition, infantcide, territoriality
what is sperm competition
multiple closely spaces mating by female or spermatozoan release is affected by presence of another suitor
what is infantcide
males killing rival offspring or competitors raiding nests
what did we look at for the gray treefrog
mate choice driven by female choice
what is kin selection
help to benefit members of pop that youre related to
what are the possible outcomes of kin selection
cooperative, altruistic, selfish, spiteful
who benefits from cooperativity
actor and recipient
who benefits from altruistic
recipient only
who benefits from selfish
actor only
who benefits from spiteful
none
what did hamilton propose
inclusive fitness in support of altruism
what is a key driving dynamic to sociality
kin selection
what are the three keys to eusociality
overlapping generations, cooperative brood care, nonreproductive castes
what groups is eusociality common in
formicidae, apidae, vespidae
how is communication done in eusocial animals
pheromones, tactile signals, visual ques
what is the r value of full siblings
0.5
what is the r value of cousins
0.125
what is hamiltons rule for altruistic allele
Br-C>0 (B is benefit to recipient, C is cost to actor)
what led to complex ant and bee colonies
kin selection
all ___ are eusocial
ants
most ____ are eusocial
bees (apidae)
what did hamilton propose is key to eusociality
haplodiploidy (XY ZW)
whats a mammal that shows eusociality
naked mole rats
what phenotypic change involves features that improve fitness
Adaptions
do adaptions happen to an ind. or a population
ind.
what type of organisms adapt with group fitness
eusocial
what are adaptions generally shaped by
environmental (Predation, competition) (abiotic)
what aspects of an organism may be enhanced with an adaption to enhance fitness
any (biochemical, physiology, behavior, life history)
how many genes are altered during adaptions
single gene to multiple genes
what organism did we study that had physical and behavioral changes to “stride on water”
water strider
what is critical for a population in order to have NS occur
genetic variation
What is a limitation in maximizing fitness
Biophysical
What is it referred to when you get really good at living in cold environments, but you cant live in warm environments
trade offs
what are three types of adaptive trade offs
energy cost
compromise of fitness for other selection pressures
loss of competitiveness
what fish occupies shallow marine waters where temp is -1.9
antantic notothenid
what protein did the notothenid fish add to adapt to the cold temps
AFGP (stops crystal growth)
what is the cTmax temp of notothenid fish where protein denaturation occurs
5 to 10 C
why do notothenids have a low solute concentration
evolves from fresh water
boney fish are thought to have ________ body fluids (solute concentration compared to sea water)
hypo osmotic
what temp does sea water freeze at
-1.86
what is the freezing point of boney fish
-.7 to -.8 C
what protein gave raise to AFGP
Trypsin
what AA sequence attaches to the ice
Ala Ala Thr
when did the boney fish evolve AFGP
30 MYA
what is it referred to when evolutionary changes in one species influence selection pressures acting on another species
coevolution
coevolution produced more effective __________ __ _________ _____________ in cooperating species
facultative to obligatory mutualism
what example did we go over that had to evolve mutualist responces to eat wood
termites
coevolution produces _________ __________ among interspecific comeptitiors
resource partitioning
what is an example of resource partitioning
finches
what is it referred to when there is coevolution between predators and preys or parasitism or herbivory
arms race
what is the hypothesis in coevolution where each organism is separately enhancing its advantage generating new selection pressures on alternate species
Red queen hypothesis
where was the red queen hypothesis derived from
Alice and Wonderland (we don’t need to know this)
what is the red queen hypothesis
if a prey improves, the predator will improve, then the prey will improve again….. and so on and so fourth
who came up with the red queen hypothesis
Leigh Van Valen
what was the example randy-jack thought was cool for the “arms race”
Newts
what does cryptic mean
camouflage
for the newt example, what was the newt genus
Taricha
what did the newt develop high levels of
TTX-texrodotoxin
what type of poison is TTX
blocks NA channels ( nerve and muscle impairment)
what did the garder snakes develop in order to keep eating the newts (red eft)
resistance to TTX
what did the newts evolve to survive
increased their ability to produce TTX
what is it referred to when ALL members of a population show common morphological bright coloration to show predators they are dangerous
aposematic coloration
what is it referred to when the environment alters gene expression
phenotypic plasticity
the ability to go through phenotypic plasticity is an __________, doing the change is not an _________
adaption
adaption
what type of phenotypic plasticity has continuous changes
continuous plasticity
What is an example of continuous plasticity
tanning, or membrane fluidity
what type of phenotypic plasticity has large-scale changes “on- off switch”
polyphenism
what is an example of polyphenism
locust migratory phase
what is the genus species name of the locust
schistocerca gregaria
what caused the physiological, morphological, and behavioral trait changes in the locust
over crowding… so toxic food
when locust eat toxic food what is the color change referred as
aposematism
who realize that the aposematism of the locust cause less prediction
G. Sowrd
what is the key to induce the migratory phase in locust
hormones
what phenotypic plasticity event is induced during the formative period of the organism and is very common in plants
developmental response
what animals were examples of the dev. response
snails and tadpoles
is the developmental response reversible
what is an example of the developmental response
no
plants…. they have roots that grow into poor nutrients, (while in formative period it was helpful, but because it is irreversible…they struggle as adults)
what was lamarks idea
He believed that an organism would adapt to its environment( not randomly)..
what involves a change in phenotype due to exposer to a specific environment
acclimation
is acclimation reversible
yes
how long does an acclimation take to occur and how long does it last
hours
days to weeks
what example did we go over for acclimation
ectothermic metabolism response to temp change
when there is a change in temperature, what is altered in ectotherms in regards to metabolism
kinetic energy and then thermal induced enzyme change
what is it referred to when there is an acclimation response to metabolism
metabolic composition
