Biologist ___________________________
Date ______________
16-1 and 16-2 – PowerPoint Notes – Darwin’s Discoveries
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Darwin’s Epic Journey
- Charles Darwin was born in ___________ on February 12, 1809.
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He grew up at a time when the scientific view of the ___________world was shifting
dramatically.
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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 
___________
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5 year voyage HMS Beagle’s five-year mapping the coastline of South ___________.
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Wanted to explain the biological diversity he observed in a ___________ way.
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Darwin noticed three distinctive patterns of biological ___________: (1) Species vary globally, (2)
species vary locally, and (3) species vary over time.
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Species Vary Globally
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Darwin noticed that different, yet ecologically ___________, animal species inhabited separated,
but ecologically similar, habitats around the globe.
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Ex: Australia’s ___________ were no where else to be found
Species Vary Locally
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Darwin noticed that different, yet ___________, animal species often occupied different
habitats within a local area.
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Ex: Galapagos Islands, which are close together but have different ecological conditions,
which lead to very distinct giant ___________.
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Ex. Darwin’s Finches beak structure varied depending on their ___________.
Species Vary Over Time
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Darwin also collected __________, which are the preserved remains or traces of ancient
organisms.
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Darwin noticed that some fossils of extinct animals were similar to ___________ species.
Putting the Pieces of the Puzzle Together
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The evidence suggested that species are not ___________ and that they could change by some
natural process.
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An Ancient, Changing Earth
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By Darwin’s time, the relatively new science of ___________ was providing evidence to support
new and different ideas about Earth’s history.
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Hutton and Lyell concluded that Earth is extremely ____ and that the processes that changed
Earth in the past are the same processes that operate in the present.
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Hutton and Geological Change
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Hutton proposed most of Earth’s features were formed from processes that operate very
________. Therefore he concluded that our planet must be much older than a few thousand
years.
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Hutton introduced a concept called ___________—the idea that our planet’s history stretches
back over a period of time so long that it is difficult for the human mind to imagine—to explain
his reasoning.
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Lyell’s Principles of Geology
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Lyell presented a way of thinking called ___________, the idea that the geological processes we
see in action today must be the same ones that shaped Earth millions of years ago.
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Darwin asked himself, if Earth can change over time, could life change too?
Lamarck’s Evolutionary Hypotheses
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In 1809, the French naturalist Jean-Baptiste Lamarck proposed the hypothesis that organisms
could change during their ___________ by selectively using or not using various parts of their
bodies.
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He also suggested that individuals could pass these ___________ traits on to their offspring,
enabling species to change over time.
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Lamarck’s Ideas
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Lamarck proposed that all organisms have an inborn urge to become more __________and
perfect, and to change and acquire features that help them live more successfully in their
environments.
Structures of individual organisms could also change if they were not ______. If a bird stopped using its
wings to fly, for example, its wings would become smaller.
Traits altered by an individual organism during its life are called ______________________ .
Lamarck also suggested that a bird that acquired a trait, like longer legs, during its lifetime could pass
that trait on to its offspring, a principle referred to as ___________ of acquired characteristics.
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Evaluating Lamarck’s Hypotheses
Today, we know that Lamarck’s hypotheses were ___________ in several ways.
Organisms ___ have an inborn drive to become more perfect. Evolution does not mean that over time a
species becomes “better” somehow, and evolution does not progress in a predetermined direction.
In addition, traits acquired by individuals during their lifetime cannot be passed on to __________.
However, Lamarck was one of the first naturalists to suggest that species are not ___________.
He was among the first to try to explain evolution scientifically using ___________ processes.
He also recognized that there is a link between an organism’s __________ and its body structures.
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Population Growth
In 1798, English economist Thomas Malthus noted that humans were being born faster than people were
dying, causing ___________.
He reasoned that if the human ___________ grew unchecked, there wouldn’t be enough living space and
food for everyone.
Darwin realized that Malthus’s reasoning applied even more to other ________than it did to humans.
Darwin had become convinced that species evolved, but he needed a scientific explanation based on a
natural process to ___________ how and why evolution occurred.
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Artificial Selection
To find an explanation for change in nature, Darwin studied ___________ produced by plant and animal
breeders.
Breeders knew that individual organisms ________, and that some of this variation could be passed from
parents to offspring and used to improve crops and livestock.
Darwin called this selective breeding process ___________ selection, a process in which nature provides the
variations, and humans select those they find useful.
Darwin put artificial selection to the test by raising and breeding plants and fancy _____ varieties.
Darwin recognized that natural variation was very important because it provided the _______ material for
evolution.
When Darwin published his scientific explanation for ___________, it changed the way people understood
the living world.