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Date: ____________ PBS Evolution
Darwin’s Dangerous Idea Charles Darwin was educated as an Anglican clergyman and strongly held to a literal
interpretation of the Bible prior to beginning his career as a naturalist. He established the
theory of natural selection following a 5-year research expedition of South America and
the Galapagos Islands. Robert Fitzroy captained the HMS Beagle. He selected Darwin to accompany him
because he was looking for someone who shared his interest in science. He was a deeply
religious man and felt guilty for playing a role in the development of the theory of
evolution. Erasamus Darwin, nicknamed “Ras,” is the older brother of Charles Darwin. He
supported and encouraged his brother throughout the development of his theory. Bishop Samuel Wilberforce was a Bishop of Oxford, a member of the house of Lords, and
a Fellow of the Royal Society – one of the oldest scientific societies in existence. He was
considered one of the greatest speakers in England and harshly criticized Darwin’s theory. Emma (Wedgwood) Darwin was the wife and first cousin of Charles Darwin.
Richard Owen was an anatomist who founded the British Museum of Natural History in London. He was one
of Darwin’s greatest critics, agreeing that evolution had occurred but by different mechanisms than random
change and natural selection.
Thomas Henry Huxley, also known as “Darwin’s bulldog,” debated Bishop Wilberforce in what would
become a key moment in wider acceptance of evolution. PBS Evolution Series Worksheets | 1 Name: _____________________________________ Class: ________________ Date: ____________ Discussion Questions
1. During Charles Darwin’s first presentation following his voyage on the HMS Beagle, he attempts to
document his evidence of gradualism – an idea he learned about from reading Charles Lyell’s book
Principles of Geology. What evidence did he present? What did he describe as the “key” to the
formation of mountains?
A lot of time is the key.
He found fossils in top where it should be miles below. 2. If the geology of the Earth changes over millions of years, then life must change with it. Describe how
Darwin made the connection between the theory of gradualism and geology and the appearance of new
species using the finches he collected on the different islands.
He found that the birds in different islands were all finches.
He believes that they changed over time in order to adapt.
Creatures who adapted to their environment lived others, did not. 3. Darwin surmised that all life on Earth was connected, like branches on a tree of life. What would the
trunk of this tree represent?
The trunk is the ancient common ancestor. 4. Biologist Chris Schneider uses the example of the leaf mantis in the rainforests of
Ecuador. How is this mantis “highly modified” compared to the ones in North
America? How would these modifications give it an advantage in this ecosystem?
The thorax and the body are flattened 5. Describe the differences in climate between the low-lying rainforest and the highelevation grasslands near the Andes Mountains. What kinds of adaptations have the scientists found in
hummingbirds that have allowed them to colonize these different ecosystems? They drop body temperature to mimic hibernation. 6. At what point are two closely related organisms (such as the hummingbirds) considered separate
If two populations change so much that they can not reproduce together, then they
are considered two different species PBS Evolution Series Worksheets | 2 Name: _____________________________________ Class: ________________ Date: ____________
7. What tool do biologists now have to compare species that Darwin did not? Using this tool, how long
ago did the highland and lowland hummingbirds diverge?
DNA 8. Charles Darwin attempts to relate his theory to his cousin Emma Wedgwood, using the selective
breeding of dogs as an example. What problem does Emma point out with his analogy?
Runts won't survive because they're too small (natural selection) and can't
create a dog with perfect features 9. After dinner with his brother, Charles Darwin looked through a book by Thomas Robert Malthus, who
believed that humanity, if unchecked, could double its population size in 25 years. Why then, wasn’t the
Earth overrun with humans at this point? How does this relate to the stoning of the Darwins’ carriage?
The earth was overrun wit humans because of natural selection (famine, war) 10. Describe the theory of natural selection, using the ideas of individual variation, limited resources, and
Natural selection says that the weakest and less
fit of the group will not survive 11. At the time of this documentary, 19 drugs for HIV were available. Explain then, using the theory of
natural selection, why AIDS could not be cured. How does the speed of change in viruses compare to
AIDS cannot be cured because by chance you have that DNA mutation. Animal
diseases are cured quicker because they either don't do anything and die or it fixes
itself. Viruses adapt to the drugs. 12. Explain how having a patient temporarily stop taking drugs can help combat the emergence of drug
By not taking drugs for a while, the virus will continue to produce the wrong or
mutated DNA. after a while, the patient starts taking the drugs again and the DNA
that will help the drug come back and outnumber the other ones. PBS Evolution Series Worksheets | 3 Name: _____________________________________ Class: ________________ Date: ____________
13. Richard Owen showed Darwin sketches of several different animal
skeletons. What did both scientists find striking about their structure?
Describe both Owen and Darwin’s explanation for this observation.
They both thought that the skeletons had similar bone structure, so they
thought it was a common ancestor. 14. The eye was cited by many as a “perfect” organ – evidence that the hand of God must have guided the
creation of man. How is the eye actually imperfect, and why are these imperfections important to
understanding its evolution?
Natural selection favors random changes, not perfect ones (more fit to survive), eyes evolve to
survive, and natural selection doesn't have an end result 15. The documentary presents a series of possible “intermediary steps” in the formation of a complex eye
organ. Explain why natural selection would favor each of these changes, and give an example of a
modern organism that still relies on that design.
a. Cup-shaped vision organ, compared to the primitive flat patch of sensory cells.
movement and flatworms PBS Evolution Series Worksheets | 4 Name: _____________________________________ Class: ________________ Date: ____________ b. Constricted eye openings.
focus light more sharply, nautilus c. A clear convex lens in front of the opening.
sharp image, monkeys 16. The publication of the book On the Origin of Species drew a lot of controversy towards Darwin and
Thomas Henry Huxley, mostly for the suggestion that humans arose by the same natural laws as all
other animals. What was the main piece of evidence used against this theory by Bishop Wilberforce and
Richard Owen? How did Huxley counter this argument?
Every living thing is equally dependents from the same ancestor. 17. What additional evidence has emerged since the publication of Darwin’s book to support the close
evolutionary relationship between humans and chimpanzees? Fossils (skeletal), DNA, natural selection, language and speech. “There is grandeur in this view of life, with its several
powers, having been originally breathed into a few
forms or into one; and that, whilst this planet has
gone cycling on according to the fixed law of gravity,
from so simple a beginning endless forms most
beautiful and most wonderful have been, and are
- Charles Darwin, On the Origin of Species PBS Evolution Series Worksheets | 5 ...
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