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Evolution
Review for UNIT TEST
Hint, Wink, Nudge, Do a Dance
Inhabiting the Earth
• Big Bang
Bacteria
Plants
Plant – Eaters
Meat Eaters
Darwin
• The process of
Natural Selection –
the biological
mechanism that
promotes the
evolution of a
species.
Genetic Variation
• Needed for Natural
Selection to occur.
• Can be caused by a
mutation or genetic
recombination.
Darwin’s Observations
• Darwin noted similarities between
species living on the Galapagos
Islands and those living on the Coast
of South America.
• Finches, plants, iguanas
His Explanation
• Ancestors of
similar species
migrated from
South America to
the Galapagos
Islands.
Adaptations
• Animals and plants develop
characteristics that allow them to
survive (eat, maintain homeostasis) and
reproduce.
Competition
The land iguana and the marine iguana
have different adaptations and occupy
different niches in order to reduce
competition between the two.
Invasive Non – Native Species
• If a non-native
animal is
introduced to
an ecosystem,
the native
species must
adapt.
Coevolution
• Animals that evolved
at the same time will
have different
adaptations that allow
them to occupy
different niches.
Evidence of a Common Ancestor
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Fossils (Transitional Forms)
Carbon Dating
Homologous Structures
Vestigial Structures
DNA Fingerprinting
Embryo Development
• All of these show the relatedness
among a species.
Carbon Dating
• The half-life of carbon – 14 is 5,730 years. If
an organism containing one gram of carbon
– 14 in its tissues died about 17,000 years
ago, how much carbon-14 is left in its bones?
Relative Dating
• No! It is not dating your relatives.
• It is looking at rock layers in order to
determine the relative age of the rock.
Homologous Structures
• Same structure, different function
• Evidence of a common ancestor
Embryology
• Embryology shows us the at early
stages all vertebrates have the same
characteristics = common ancestor.
Transitional Forms
• Intermediate
stages found in
the fossil record
between the
common ancestor
and the present
stage of an
organism.
Kettlewell’s Experiment
• Before the industrial revolution there
were many white moths, and very
few dark moths – because the trees
were white.
After the Industrial
Revolution
The trees are covered in
soot, so white moths are
more easily seen and
get eaten, leaving dark
moths to survive and
reproduce.
Increase in dark moths
due to natural selection
Kettelwell’s Hypothesis
• Based on his
observations,
Kettelwell
hypothesized that
moths whose body
color matches the
color of the tree bark
are more likely to
survive.
Evolution of the Horse
Summary:
Horses have
undergone several
changes that are
evident in the fossil
record.
Classification
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Kingdom
Phylum
Class
Order
Family
Genus
Species
Classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order:
Perissodactyla
Family: Equidae
Genus: Equus
What makes a species?
• In order for two
organisms to be
considered
members of the
same species
they must be
able to produce
fertile offspring.
Hominid
Evolutionary
Tree
Able to determine
the ancestors of
human.
Evolution of Primates
• Paleontologists can distinguish an ape
skull from a human skull by the size of
the cranial cavity.
• Several species developed and then
became extinct, leaving no
descendants.
• Fossil evidence suggests that human
beings did not evolve from modern
apes.
Comparing Amino Acid Differences
Number of Amino Acid
Differences when
compared to human
hemoglobin = 0
They are most closely
related to humans.
Artificial Selection
• When HUMANS
intervene.
• Change the
genes of plants
or animals.