1. Intrapopulation variations can be genetic or non-genetic. Non-genetic variations include individual, social, ecological, and traumatic variations. 2. Individual variations over time include age variations, seasonal variations within an individual's lifetime, and seasonal variations across generations. 3. Social variations occur in social insects where there are distinct castes or groups within a colony serving different functions. 4. Ecological variations arise from differences in habitat, climate conditions, host organisms, population density, growth patterns, and neurogenic responses to the environment.

1. Intrapopulation variations
I. Non-genetic
II.Genetic
Non- genetic:
i.Individual variationin time
ii.Social variations
iii.Ecological variations
iv.Traumatic variations
I.Individual variations intime:
 Age variations
 Seasonal variations of an individual
 Seasonal variations of generations
Age variations:
Animals ingeneral pass througha series of juvenile or larval stages inwhich
they may be quite different fromadults e.g the immature stages of the
eel(Anguilla) were originally describedas LeptocephalusbrevirostrisKaup.
Similarly the difficulties for the taxonomist are evengreateringroups with
larval stages whichare so different that they have not eventhe faintest
resemblence tothe adult(e.g catterpiller andbutterfly)
Seasonal variations of the same individual:
In animals that live as adults throughseveral breeding seasons,it sometimes
happens that the same individual has a very different appearance indifferent
parts of the year.In arctic and subarctic birds suchas Ptarmigans ,there may be a
change from a white winter dress toanormally colouredsummer dress .
Rock ptarmiganin summer:grey and brownupperparts;

2. In winter:white plumage
In the europeonstarling (Sturnus vulgaris) the freshly moltedbirdof october is
coveredwithwhite spots andall the feathers showwhittishmargins.During
winter the edges of the feathers wears off ,and in the spring,at the beginning of
the breeding season, the whole birdis a beautiful glossy black without the molt
of a single feather.
Seasonal variations of consecutive generations:
These variations are calledpolyphenisme.g Africanbutterfly Bicyclusanynana.
Wet seasonform --- eyespots along the margin(onventral side) Dry seasonform
– very small or almost no eyespots
II.Social variations:
In social insects like honey bees there are definite groups of individuals withina
colony inaddition tothe reproductiv castes(Queenandmales or
drones),workersandsoldiers.The drones are the males ina bee colony. They are
the product of unfertilized eggs.The queenis one of many females inthe colony;
however, she is the only one that is developedspecifically for laying eggs.The
queenis the product of a fertilizedegg that is fedan abundance of royal jelly
during its development
They are all females and, thus, come from fertilizedeggs. The workers are the
majority of the population of the colony. There are about 2,000 to60,000
workers per colony
III.Ecological variations:
a.Habitat variation
b. Variationinducedby temporary climatic conditions
c.Host-determinedvariations
d.Density dependent variations

3. e.Allometric variation
f.Neurogenic color variations
Habitat variations:
Populations of a single species that that occur indifferent habitats inthe same
regionare oftenvisibly different.Dall gave avery instructive account of all the
variations he observedina study of the oyster(Crassostreavirginica).Whena
specimengrows instill water,it tendstoassume amore roundedor broader
form.Whenit grows in a strong current the valves become narrowand
elongated,usually alsoquite striaght.
When an oyster grows incleanwater on a pebble,whichraises it slightly above
the bottom level,thelower valve is usually deepandmore or less sharply
radially ribbedacquiring thus a strength whichis not neededwhenthe
attachment is to a perfectly flat surface whichacts as a shieldon that side of the
shell..for the same reasonoysters whichlie ina muddy bottomwith only parts
of the valve s above the surface , are less commonly ribbed.
Variations inducedby temporary climatic conditions:
Some animals witha highly plastic phenotype may produce year classes that
differ visibly fromthe norm owing tounusual conditions(drought,cold,food
supply).
Host determinedvariations:
Gerouldhas reportedthat the braconidwasp Apanteles flaviconchae,spins
white cocoons when rearedfromblue-greencatterpillers of Coliase philodice,
but goldencocoons when rearedfromyellow-greencatterpillers fromthe same
species.
Density dependent variations:
Kennedy and others have shownthat gregarious species of locusts exist in
various unstable biological phases.these phasesdiffer inanatomy,color and
behaviour characteristics andhave oftenbeendescribedas distinct

4. species.Whennewly hatchednymphs are rearedunder crowdedconditions,they
intothe transitional phase and whenisolatedand rearedseparately,intothe
solitary phase.
Allometric variations
Allometric growthresult inthe disproportionate size of some structurein
allometric growth,animals of different size will showallometric variability.
Neurogenic variations:
Neurogenic variationis color change inresponse tothe environment.
Chameleons have specializedcells, chromatophores, whichcontainpigments in
their cytoplasm, inthree layers belowtheir transparent outer skin.The
chromatophores inthe upper layer, calledxanthophores anderythrophores,
containyellowand red pigments, respectively. Belowthe chromatophoresis a
secondlayer of chromatophores callediridophores or guanophores;these
containguanine, appearing blue or white.The deepest layer of chromatophores,
calledmelanophores, containthe dark pigmentmelanin, whichcontrols how
much light is reflected.
Chameleonchange color in reactiontotemperature as well as to
camouflage.Different chameleonspecies are able tovary their colorationand
patternthroughcombinations of pink, blue, red, orange, green, black, brown,
light blue, yellowand purple
Accidental andteratological variations
undergometamorphosis, injuries toanearlier stage may produce later
abnormalities whichare not so easily recognizedas such.this is especially true
when the anomalies involve characters whichare normally of taxonomic value
in the group concerned.e.g symmetrical modificationof wing pattern.
Post mortemchanges:

5. In many group of animals it is impossible toprevent post-morteumchanges of
preservedspecimens.Some extremecases are knowninbirds.e.g deeporange
yellow plumes of twelve-wire birds of paradise(Seleucidisignotus) fade in
collectiontowhite -skinof chinese jay(Kittachinensis) whose plumage is green
in life,turnblue incollections -
overexposedtocyanide turnbright red.
Genetic variations:
1.Sex-associatedvariations
A.-Primary sex differences
B.-Secondary sex differences
C.Alternating generations
A.Primary sex difference:
These are differences involving the primary sex organs utilizedinreproduction.
They are rarely a source of taxonomic confusion.
B.Secondary sex differences:
sexual dimorphism
-in some cases male and female are strikingly different fromone another
Examples :King parrot Eclectus roratus :
Male--------greenwithanorange bill
Female-------redandblue withblack bills
Mutilidwasp:Small wingless female
Large wingedmale
C.Alternating generations:

6. In aphids the parthenogenetic winglessfemales are usually different fromthe
wingedfemale of the sexual generations.
2.Nonsex associatedvariations:
A.continous variations
B.Non-continous variationss
Continous variation is the result of slight genetic differences whichexist
betweenindividuals.Itis nowevident that no one individual is “typical”of the
characters of a populations.only the statistics of the whole populationcan give a
true picture of the population.114 speciesof the snail genus melaniawere
found to be nothing but individual variants .
Discontinous variation:Incertainspecies,the members of apopulation can be
groupedinto very definite classes,determinedby the presence of certain
conspicous characters.suchdiscontinousvariations is called
polymorphism,commonalfalfa butterfly ---Coliase eurytheme—has two
strikingly different female forms-oneresembling the orange coloredmale while
the other is largely white