AP BIOLOGY
NAME:____________________________________
DATE:__________________________PER:______
CH. 22
“Descent with Modification”
Darwinian EVOLUTION
 EVOLUTION = “descent with ___________________”

a ___________ over _________ (______________ change) in the _______________
composition of a population.

can possibly result in enough genotypic & _________________ changes that result
in new ____________!
 Occurs THROUGH _______________ _________________!
 NATURAL SELECTION: (___________________________________________________________)
o “_____________ _____________” specific ___________/________________ that a better
suited for survival in a particular _________________ at a particular __________.
o a ________________ can ___________ over generations if individuals that possess
certain heritable traits leave more ______________ than other individuals.
o acts on _________________.
o Darwin proposed that species ___________/____________ through the process of
_____________ _______________.
 ADAPTATION: certain traits/_________________ that increase an __________________
chance of _______________, because it is “well suited” to a particular _________________.
 See Fig.22.6:

Beak variation in Galapagos
Finches.

Different ___________ =
_______________________________
_______________________________
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 EVOLUTIONARY ADAPTATION: the result of _____________ ________________.
o an accumulation of inherited characteristics that enhance organisms' ability to
______________ & _______________ in specific __________________.
 Lamarck's Theory of Evolution: (____________________)
o "Use & disuse" - the idea that parts of the
________ that are used a lot become larger
& _____________, while those that are not
used deteriorate.
o "Inheritance if acquired traits" - states that
an organism could pass modifications/acquired
traits to its offspring.
o Also proposed the idea that organisms have an innate drive to become more
complex.
King
KINGDOM
Philip
PHYLUM
Came
CLASS
with _____________ & _________________
Over
ORDER
living ________________.
From
FAMILY
Germany
GENUS
Soaked
SPECIES
 TAXONOMY: the branch of biology concerned
 FOSSILS: remains or traces of _______________
from the _________.
o most fossils are found in sedimentary
________________
rocks formed from the sand and mud that
settle at the bottom of ________, ___________
and marshes...then new layers of sediment
cover older ones and compress into
superimposed layers of rock called strata (pl.)
(singular: ______________), which can then be
studied to show relative _________ periods and
the types of organisms (___________) that are
found within that period.
--> ____________ ______________!
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__________________
 DESCENT with MODIFICATION: (see Fig.22.7)
all organisms have a common ancestor but have _____________ over __________ by
_______________ traits. (i.e.________________)
"TREE of __________"!
o can explain why certain characteristics in related species have an underlying
similarity even though they may have very different functions (HOMOLOGY).
 See Fig.22.8 - Descent with Modification

This evolutionary tree of elephants & their relatives is based on
_____________, their anatomy, & geographic distribution.
 GENETIC VARIATION:
o the natural genetic __________________
between members of the same _____________.
(See Fig.22.9)
Both of these
pictures show
_________________
within a
_________________.
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 EVOLUTIONARY ADAPTATION:
the result of _____________ ________________.
o an accumulation of inherited
characteristics that enhance organisms'
ability to ______________ & ________________
in specific ___________________.
______________________
__________________
 ARTIFICIAL SELECTION: the process of humans modifying species over generations
by selecting and breeding ________________ that possess desired __________.
o ex: __________, ____________, _____________________
o results in domesticated animals bearing little resemblance to their wild
_________________.
o aka _______________ _________________
 See Fig.22.9:

Original wild natural species:
______________________

Artificially bred/_____________ species:
_____________________________________
_____________________________________
 VESTIGIAL ORGANS:
o structures that seemingly have little or
_____ use to the _______________ (______________).
o remnants of structures that served a
function in the organism's _____________.
 Vestigial organ:
__________
o Ex: __________________________________________________________________________
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 HOMOLOGY: [“homo” = __________  _________ source/origin]

underlying similarity between related species with common _______________,
even though they may have very different functions.
 See Fig.22.15:

Anatomical similarities in
vertebrate embryos.
 Implies ____________
from a _____________
ancestor.
 HOMOLOGOUS STRUCTURES: structures in different species that are ______________
because of ____________ ______________.
o Ex: __________________________________________________________________________
o SEE Fig.22.14/22.17
 See Fig.22.14/22.17:

Mammalian forelimbs: ______________________ structures.
 have become adapted for ___________________ functions,
but all constructed from the same basic skeletal elements.
(same _______________).
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 NATURAL SELECTION & ADAPTATION
 How does NATURAL SELECTION work??? & how does it explain
ADAPTATIONS???
 3 inferences, BASED ON 5 observations!:
o OBSERVATION #1: For any species, population sizes would
_____________ exponentially if all individuals that are born, survived &
_________________ successfully.
o OBSERVATION #2: Nonetheless, populations tend to remain __________
in size, except for seasonal fluctuations.
 Why?
o OBSERVATION #3: Resources are ______________.

Ex of resources: _______________________________________________
INFERENCE #1: Production of more individuals than the
environment can _____________ leads to a struggle for
existence (_________________) among individuals of a
population, with only a fraction of their offspring surviving
each ________________. (______________ of ______ _____________)
o OBSERVATION #4: Members of a population vary extensively in their
characteristics; no ___ individuals are exactly alike;
(_______________ ________________).
o OBSERVATION #5: Much of this variation is ______________.
INFERENCE #2: Survival depends in part on ______________
traits. Individuals whose inherited traits give them a high
probability of surviving & _______________ in a given
________________ have higher fitness & are likely to leave
more ______________ than less fit individuals. (______________
of the _____________!)
INFERENCE #3: This unequal ability of individuals to
_____________ & _______________ will lead to gradual ___________ in a
population, with favorable __________ accumulating over generations.
 Darwin's theory of natural selection as the mechanism of evolution in
populations is evidenced by the vast _____________ we see among living things
(_____________ of __________!)
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 SUMMARY of NATURAL SELECTION:
o
Natural selection is the differential success in ________________ among
individuals that vary in their heritable __________. These reproductive
differences emerge as each individual interacts with its _________________.
o
Over time, natural selection can _____________ the adaptation of
organisms to their ________________.
o
If an environment changes _________ __________, or if individuals of a
particular species move to a new environment, _____________
______________ may result in adaptation to these new conditions,
sometimes giving rise to new ___________ in the process.
 Remember!:
o The process of evolution happens _________ _________ in response to
___________ in the _______________.
o Evolution results from ______________ ________________ (the mechanism)
o Environmental factors vary from place to place and from ________ to
________.
* A trait that is favorable in one situation may be useless, or even
detrimental, in different circumstances.
** Favorable traits in a specific environment are not "created" in the face of
change, but are "selected for" as individuals that possess those favorable
traits survive, passing on their _________ for those _________ to the next
______________, while those that do not possess those favorable traits,
________, thus NOT passing on their genes to the next generation.
o Natural selection is always operating, but which _________ are favored
depends on the ________________ at a particular _________.
 MAKE SURE to read the examples in CH.22.3 of "Differential Predation" &
"Guppy Populations" & "The Evolution of Drug-resistant HIV"
 READ white EVOLUTION PACKET & tan Ch.22 Summary packets!
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