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EVOLUTION
Brianna Manuel, Emma Page
Stacia Paglieri and Georgia Pullis
CHARLES DARWIN
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Charles Darwin discovered the beginning of
evolution. In his theory, he had an idea that
animals could change through time.
Darwin found that different birds could have
different beaks depending on where they lived
and what type of food they ate.
He soon realized that species of animal can
change through time, according to the animals
environment.
DARWIN’S JOURNEY
 In
1831 Charles Darwin set off on a scientific
expedition on the ship H.M.S. Beagle
 During the five-year trip, Darwin took notes
and a few special specimens for later
studying
 He was most successful on his visit to the
Galapagos Islands
 After the voyage Darwin discovered he had
collected different varieties of the same
species
 He came up with a theory of evolution
DARWIN’S THEORY
A species is a population of organisms that breed
with each other to produce more offspring.
 Living organisms have been passed down
modifications from those, in the species, that
have lived before them.
 Natural selection is the explanation of evolution.
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NATURAL SELECTION
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Natural selection is when types of animals in a
species die because they are not able to live in the
environment. Therefore, the surviving organisms
pass down traits to their offspring for survival.
Resources may be limited because of overreproducing of organisms. There is competition
for resources such as shelter and food.
NATURAL SELECTION
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Individuals in a population have different traits
and some of these traits are passed on to
offspring if they are traits that offer success.
Some organisms are more adapt to survival than
others because of mutations that have been
passed on.
Those who are able to survive pass on their genes
to their offspring; those who are not able to
survive become extinct.
EVIDENCE OF EVOLUTION
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Homologous Structures:
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Analogous Structures:
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Similarities in ancestors
Similarities in looks and functions
Vestigial Structures:
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Helpful functions for ancestors, but not for modern
organisms
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Embryology Similarities:
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Different embryo’s show similarities proving they
originated from the same ancestors
Macromolecules Similarities:
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The more similar a species homologous proteins, the closer
the species’ are
ISOLATION
 Isolation
happens when two parts of a
interbreeding population stop interbreeding.
There are two specific types that create
species’.
 Geographic Isolation:
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The physical separation of populations such as by climate
change
 Reproductive
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Isolation:
Barriers between breeding of a population in a certain area
FOSSILS

Fossils trace old, dead organisms, often found in
sedimentary rock and formed by sediment
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Sediment is made out of things like dust, sand or
mud, which is deposited by wind or water
Fossils give us evidence of past organisms and
how they evolved to be the modern organisms
that we see today.
PATTERNS OF EVOLUTION
There are many ways that animals can change to
adapt to their habitats and the pattern.
 The speed of this change depends on the changes
in the environment.
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When there is a change within a species that is in
close association with one another, it is called co
evolution. Predators and prey often co evolve with
each other. An example is animals that pollinate the
plants.
 When
organisms appear to be closely related
but are actually different from each other, it is
called convergent evolution.
 Convergent evolution happens when the
environment selects similar phenotypes,
even though the ancestors were very
different from each other.
 An example is sharks and porpoises. Sharks
are fish and porpoises are mammals, but
their features are similar and they share the
same environment.
 When
two or more related species become more
and more dissimilar, it is called divergent
evolution.
Divergence is usually a result of differing environments. It
can eventually result in making a new species.
 Adaptive radiation is one important type of divergent
evolution. This is when many species evolve from a single
ancestral species. Darwin discovered this when he studied
the Galapagos tortoises.
 Artificial selection is when the process of divergence is sped
up artificially. An example is how different dogs are bred by
humans.
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VARIATION IN TRAITS
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Within a population, the observable traits of an
individual can vary. For example, in a population
of fish, the fish can vary in size.
In populations, things like height and weight tend to
show a variation pattern in a bell curve.
 Biologists can study the variation of traits within a
population by measuring that trait in a large sample.
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CAUSES OF VARIATION
Variation can be influenced by environmental
factors like the amount and quality of food. It is
also influenced by heredity.
 Parents produce several children, but all are
different. Variation is found among the children,
who have varying genes. Generations of species
can look similar, but they have differences.
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Variation in genes can happen in three ways
Mutation: this is a result from flawed copies of individual
genes.
 Recombination: this is the reassociation of genes in a
certain individual. This occurs during meiosis.
 The random fusion of gametes: this is mostly a game of
chance by individual gametes. There are millions of sperm
involved in mating and it is just a matter of chance which
one fertilizes the egg. This process makes sure that
offspring are not complete copies of their parents.
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THE QUESTION
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Where do the species on Earth come from and
what is the role of extinction?
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There are many theories about how life began, but
the world is ever-changing and new species are
always being found. These species have evolved from
past species through mutation. This is evolution.
Evolution is how the species eventually change there
observable traits to adapt to their ever-changing
environment.
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Extinction is a major part of evolution.
Many of the ancestors of species are now extinct because
they were not fit to survive their environment. These
ancestors helped in the process of evolution. Before they
became extinct, they created a new generation. This
generation was mutated by the different genes of the
parents and made more fit to survive the environment.
 Extinction is important to evolution because, to make new
species that can survive our environments, old species need
to die out.
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EVOLUTION WITH THE EARTH
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Our starship earth is very important to us. We
need all of our animals to survive and keep the
circle of life in motion.
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Evolution brings us the best of certain species of
animals and they become the best in the best of ways.
Through natural selection, earth chooses her own
inhabitants. We as humans are lucky to be a part of
the Earth as we know it. We are even a part of
evolution.
SOURCES
http://www.tutornext.com/system/files/u81/chapte
r%209-final-9.gif
 Modern Biology– Holt, Rinehart and Winston
 All pictures are from google
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