Transcript changes in the frequency of alleles (called ______)

Natural Selection
The members of a species that live in a specific area
population
are known as a _____________.
There are many different populations in a single
ecosystem. Each population of organisms has a
______ to play in the role
ecosystem. It can be a
predatoror it can be
_________ and eat another species,
prey
the _______ of another predator.
It might recycle nutrients as a decomposer or
create sugars as a producer at the foundation of a
food chain.
Some organisms, like trees, provide shelter for
many different communities.
The role that an
organism plays in
the ecosystem is
known as its ______.
niche
Within a population of organisms, there are many
genesmight be more
versions of certain ________. There
than one version of the gene for hair color, so that
some animals are _______ while others are
gray or _______. The different
brownversions of a
________
gene
white
are known as ________.
alleles
Genotype for Fur
Color
Phenotype for Fur
Color
Subject A
Subject B
Subject C
GG
Gg
gg
Gray Fur
Gray Fur
White Fur
frequency refers to how common a
The ________________
certain allele (version of gene) is within a
population. If almost all of the animals in a
population have brown fur, than we would say
frequency
the _______________ for brown
fur is high.
Random changes in the frequency of an allele
occur all of the time. This is known as
genetic driftand many different things can
_____________,
cause it.
1. Genetic drift can be the result of ________
randomIf a population of plants is mostly tall, it
mating.
can become shorter and shorter simply by
________. The shift inchance
the frequency of the tall
allele is called _____________.
genetic drift
2. _________
Plagues and ___________
epidemicscan randomly
affect the frequency of a gene. The number of
animals in a population with gray fur might be
decreased ___________ because ofrandomly
a new virus
which killed a large number of animals with gray
fur. This change in the frequency of the allele for
gray fur is known as _____________.
genetic drift
3. A small group of organisms from the population
migrate
might ________ to a new
location and start a new
population. If the original population was mostly
________ hair, but the new population
had an
brown
unusually high percentage of _______ haired
individuals, then thered
new population will _______
towards a higher percentage of red drift
hair. This form
of genetic drift is known as the ______________.
founder effect
Some alleles make it
easier for an organism
to _________. Once
survive________ has
random
changed inchance
the
___________ of the
frequency
alleles,
the organisms
which have the alleles
best _________ for the
new environment will
adapted
survive
the longest and
pass their genes down
to their ___________.
Theadaptation
process of organisms with the best _____________
genes
surviving to pass their ________ down to their offspring
is known
as
_________________.
natural selection
The _________________
peppered moth is a classic example of
natural selection in action. Before the industrial
revolution, the moths were mostly a light grey
color which allowed them to hide from
predators
__________ by blending in with the
bark of trees
while dark moths were easily spotted and eaten.
After the industrial revolution began, the _______
black
soot
from the factories began to cover the trees.
The grey moths were now easily spotted and
eaten by birds, but the few ______ moths were
dark
now very
well camouflaged.
The variation or __________
diversityof the moth
community allowed them to survive. The dark
moths were now the best adapted and were able
to live and reproduce because of the process of
natural
selection
________________. Now
most
of the moths are
_______ instead of the original
dark
light grey.
If two populations of the same species become
adapted
__________ to different environments, the processes of
natural selection
_________________
and _____________ will cause
genetic drift
them to change so much that the two populations will
become different _________. The process two
species
populations of the same species becoming two
different species is known as _____________.
speciation
____________
Phylogeny is the study of the relatedness of
organisms. This is very closely related to the subject
taxonomy
of ____________ which
deals with placing organisms
into kingdoms.
Scientists examine organisms and _______ infer
where
the process of speciation has occurred. To show
these conclusions, they create a diagram known as a
__________________.
phylogenetic tree
closest
The organisms which are _________ to each other
most
on a phylogenetic tree are the _______ related.
The organisms which are __________ from each
farthest
other on
the tree are the ________ related.
least
In order to draw their conclusions about the
relatedness of animals, scientists often compare
genes
the _______ found
in each organism. If the genes
of two organisms are very similar, then the
organisms are assumed to be very closely related.
Since the genes in DNA are translated into
proteins
__________, these are often compared as well as
their
physical structures or __________. The
anatomy
organisms which are most similar are considered
to be the most
closely _________.
related
Orangutan
Dog
Swine
Cattle
Tapir
Horse
Organismsare
Q and
Organism
R related?
Which two organisms
the most
closely
___________________________________________
How can you tell?
__________________________________________
They have the most in common!
Most scientists believe
that the great variety or
diversityof life on the
___________
planet is because of a
combination of changes to
DNA (called __________ ),
changes in the frequency
mutations
of alleles (called
_____________) and the
process of the organisms
with the best
genetic
adaptations
drift
surviving and having
offspring (called
_________________).
Photo © 2004 Richard Ling
The first life form was believed to be a ___________.
Thisprokaryotes
is where the name comes from since pro- is a
before
prefix meaning ________.
The processes of
mutation, genetic drift
and natural selection
are believed by many to
have begun with a
simple prokaryote and
continued over great
amounts of time until
all of the great variety
or __________ of life
was formed.
diversity
Photo by Luc Viatour
The theory that a series of random __________
mutations
coupled
with the process of natural ___________
resulted in selection
all of the life forms on the planet is
known as ___________. The first scientist to
evolution
popularize
this idea was named _______________.
Charles Darwin
This is why when an organism is very well
adapted to a certain environment, scientists
evolved
assume that it __________ in that
environment.
If a plant can tolerate snow, then they say that it
_________ in a cold environment.evolved
It is also why animals with similar characteristics
are assumed to
common ancestor
have evolved from a _________________. Birds, reptiles,
amphibians and mammals
are all considered ____________
vertebrates
because they all have a backbone. Scientists assume that all of
these very different organisms evolved from acommon
________________
ancestor
which had a backbone.