Download Evolution Notes

Theory of Evolution:
Change in living organisms over many
successive generations.
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http://science.nationalgeographic.com/science/prehistoric-world/prehistoric-time-line/
COMMON ANCESTOR:
an organism from the past in which present organisms
have evolved from
PRESENT
PAST
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 Fossil: Preserved remains or evidence of an ancient
organism.
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 The lower the layer
is, the older the fossil
is.
 The higher the layer
is, the younger the
fossil is.
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 Homologous Structures: organisms with similar
structure, but different function.
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 Analogous Structures: Different structure, similar
function. These organisms DID NOT inherit their
structural adaptations from a common ancestor.
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 Vestigial Structures: a structure that is no longer used
by an organism, but is found in closely related species.
(Ex. Human appendix and tail bone, penguin wings,
whale hip bone).
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 Comparative Embryology: the study of early embryo
development
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 Comparative Biochemistry: comparing the DNA or
amino acid sequence of organisms
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 Charles Darwin: The founder of the theory Natural
Selection and author of “Origin of Species”
It is not the strongest of the species that survives,
nor the most intelligent that survives.
It is the one that is the most adaptable to change.
-Charles Darwin, Origin of Species
Adaptations (structural and behavioral):
inherited characteristics that increases an organisms
chance of survival and opportunity to reproduce in it’s
niche.
 Natural Selection: a process by which individuals that
are better suited to their environment survive and
reproduce most successfully
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1.
Overproduction – Each species produces more
offspring than can survive.
2.
Genetic Variation – Individuals in the population
have different traits. (ex. Different fur color, size of
claws, length of tail).
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3. Struggle to Survive – The natural environment can not
support all organisms. This can lead to competition of
food, shelter & mates.
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4. Reproduction: The organisms that are well adapted to
their environment reproduce and pass the favorable
traits to their offspring. Those who survive &
reproduce are considered “the fittest”.
- Charles Darwin from Origin of Species
“Light” colored pepper moth
“Dark” colored pepper moth
 The Peppered Moth is a species commonly found in
the countryside of Britain. There are two versions of
the peppered moth. The peppered moth lived in an
environment where trees had light colored bark.
Which kind of peppered moth was more favorable to
survive? Why?
 Coal burned during the early decades of the industrial
revolution and produced soot that blanketed the
countryside of the industrial areas of Britain.

Naturalists noticed a change in the peppered moth
population...
Before Industrial Revolution
After Industrial Revolution
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 Some species have evolved physical adaptations that
allow them to blend with their environments.
Camouflage allows organisms to become invisible to
predators. As a result, more of the camouflaged
individuals survive and reproduce.
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One species evolved to resemble another species.
Harmful species
Harmless species
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
Species of bacteria that originally
were killed by penicillin and other
antibiotics have developed drug
resistance. For almost every
antibiotic, at least one species of
resistant bacteria exists.
 One unintended consequence of
the continued development of
antibiotics is that some diseases,
which were once thought to be
contained, such as TB, have
reemerged in more harmful forms.
Genetic Change!
Nucleotides or genes of DNA/RNA can change
randomly (mutations). This can lead to a new
variation of an organism, this may or may not give the
organism an advantage to survive.
A group of similar organisms that can successfully breed
AND produce fertile offspring.
 Mules are infertile!!!