Download Darwin*s Voyage - Miami Beach Senior High School

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Darwin developed a scientific theory of
biological evolution that explains how
modern organisms evolved over long periods
of time through descent from common
ancestors.
He sailed on HMS Beagle around the globe
collecting plant and animal specimens.
Darwin noted that 1) species vary globally
2)species vary locally and 3) species very over
time
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Darwin noticed that different, yet
ecologically similar, animal species inhabited
separated, but ecologically similar, habitats
around the globe.
(Rheas, large flightless birds, live in the
grasslands of South America look like
ostriches, yet ostriches live only in Africa)
Why are there no kangaroos anywhere
except in Australia?
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Darwin noticed that different, yet related,
animal species often occupied different
habitats within a local area.
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In addition Darwin collected fossils. Some
looked similar to living species while others
did not.
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Darwin noticed that some fossils of extinct
animals were similar to those alive today.
Why did they disappear?
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Hutton – geologist. In 1785 he hypothesized
that slow acting geological forces shaped the
planet. He estimates Earth to be millions, not
thousands of years old.
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Lyell published “Principles of Geology” in
1830- the same processes affecting Earth
today have shaped Earth’s ancient geological
features.
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Lamarck -1809 – suggested that organisms
could change during their lifetime by
selectively using or not using various parts of
their bodies. He also suggested that
individuals could pass these traits on to their
offspring, enabling species to change over
time.
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In 1798 Malthus
reasoned that if the
human population
continued to grow
unchecked, sooner or
later there would be
insufficient living space
and food for everyone.
 He found that any
When Darwin
domesticated plant or animal
returned home he
bred to accentuate desirable
studied and read
characteristics is the result of
other people’s
artificial selection. (Nature
materials about
provides variation and humans
geological changes.
select the variations that they
 He also studied the
find useful)
selective breeding of
 Many vegetables that we eat
domestic animals
today came from the wild
and crops.
mustard plant through
artificial selection.
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Darwin’s book, published in 1859, was a quick
success. It came from the clear and understandable
argument that natural selection and selective
breeding of animals was in wide use at the time.
There was a massive array of biological and fossil
evidence to support the argument.
Selective breeding: breeding of organisms to
produce certain desired traits in their offspring. It
came from the argument that natural selection and
selective breeding of animals was in wide use at the
time. There was a massive array of biological and
fossil evidence to support the argument.
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Individuals that are best suited to an environment
(adaptations that enable fitness) survive and
reproduce most successfully.
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Over time, natural selection results in changes in
the inherited characteristics of a population. These
changes increase a species fitness in its
environment.
4 Main Points.
1.
2.
3.
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5.
There is variation with a
population.
Some variations are
favorable.
Not all young produced in
each generation survive.
Individuals that survive
and reproduce are those
with favorable variations.
Descent with
Modification
Ostriches are the fastest birds on land due to favorable
traits such as long, powerful legs.
 Natural Selection leads to organisms
that are well suited in particular
environments.
 It provides a scientific explanation for
the history of life on Earth as
depicted in the fossil record and
similarities evident within the
diversity of existing organisms.