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16.1 and 16.2 Darwin’s Voyage of Discovery

Questions Answers

1. Briefly explain the three patterns of variation Darwin noticed (global, local and over time) (16.1) Global- He noticed that similar species inhabited ecologically similar places across the globe

Local- Noticed that different but closely related species inhabited different habitats within a close area.

Over time- Fossils of dead species looked very similar to living animals.

2. From where did Darwin believe the Galapagos species originated? What evidence did he have to support this? (16.1) He believed that they originated from the South American mainland.  The Galapagos species were found nowhere else except the mainland, which they resembled a similar species.
3. Who were Hutton and Lyell? How did their conclusions support Darwin’s theory? (16.2) Hutton and Lyell were Geologists  that concluded that the earth had to be more than a few thousand years old for certain rock formations to appear.  They supported his theory because Darwin believed that evolution would take more than a few thousand years as well.
4. Lamarck gets a bad rap because his theory is completely refuted by the way that genes and heredity work. However, Lamarck died when Gregor Mendel was only seven years old, so his ideas were just before their time.

Describe how Lamarck’s theory compares to Darwin’s. How are they similar? How are they different?  (16.2)

Both theories say that animals change over time, however Lamarck’s sais that animals will change to achieve perfection within its lifetime.  Like if a mouse’s tail is cut off, then it will grow back in its lifetime.  Darwin’s theory says that organisms will change over lifetimes.  
5. Who is Thomas Malthus? What idea from the ecology unit does his work relate to? How did this relate to Darwin’s theory? (16.2) Malthus is an economist who predicted that low survivors naturally kept the population low.  It works into the population density and size unit.  It relates to Darwin’s theory of natural selection because the ones that are not fit to survive are eaten, keeping the population low.
6. Give two examples of artificial selection used today – one for plants, and one for animals. (16.2) We breed cats and dogs to have nice colours and have good temperment for families, or an attack animal to keeps unwanted people out.  We also breed corn to be bigger and sweeter.


16.3 Darwin Presents His Case

Questions Answers

1. Darwin’s theory is dependent on a few basic requirements. Explain why the following MUST be true in order for natural selection to act upon a species’ traits:

  1. Struggle for existence
  2. Variation and adaptation
  3. Survival of the Fittest
  1. This acts on competition of food when a population grows too large.
  2. Species adapt to survive better, they change to their surroundings.
  3. Only the best organisma ca live, which is how species stay alive.
2. What is an adaptation? Can an individual organism adapt? Why or why not? An adaptation is a change in a species that helps fix a problem in survival.  They cannot change in a lifetime because adaptations are genetic, and you cannot change your genotype.
3. A common misconception is that natural selection is the process through which a species “improves” or “gets better”. Explain why this is not true. An adaptation is usually a mutation, so it could negatively impact a species.
4. Many people think that “common descent” means that humans evolved from chimpanzees. Explain why this is NOT true. Apes evolved separately into chimps and humans, they are both separate species.


16.4 – Evidence of Evolution

Questions Answers

1a. Give an example of two species that are closely related but different

1b. Give an example of two species that are distantly related but similar (You may have to answer this question LAST. It’s an important idea to come back to)

  1. The Finches on the Galapagos Islands.  They are all finches, but have different aspects about them that make them different.  
  2. The Emu on Australia and another bird on South America.  They both have very similar bodies but are different in structure.
2. What two major types of data have been collected since Darwin’s time that support his theory about the true age of the Earth? Vestigial organs help prove his theory because the animal evolved to not need what they were originally intended for.  Also some fossils show the changing of evolution.  
3. What is a homologous structure? What evidence about a species ancestry does it provide? Why do the organisms look so different today? They are structure shared by many species, indicating a common ancestor.  Organisms look different today because they have evolved in different ways from the same ancestor.  Each one doing different things.
4. Organisms with analogous structures are not actually closely related. Why might analogous structures have confused Darwin? They may have been confusing because they have a similar function, but are  made differently.  There is no common ancestor, only a common ecosystem.
5. How is a vestigial structure similar and different from a homologous structure? They are similar because they both come from a common ancestor,  however the vestigial structures no longer have any use to the organism.
6. What is embryology, and why do evolutionary biologists love studying it so much? It is the study of how embryos turn into fetus’s.  They like to study it because it can help determine which species are descended from a common ancestor.

a. Molecules can actually be homologous. DNA is the ultimate homologous structure. Explain what I mean by that.

b. How do genetic mutations lead to evolution?

c. How does genetic homology between species (the noun form of homologous) help us in modern-day research of human genetics? (Hint: Think about how all genetic research starts. We can’t easily experiment on humans…)

  1. You mean that everything is made up of DNA
  2. If a genetic mutation helps an organism and is dominant, then it will help future generations of that species.
  3. The more genes you share the more closely related the species are.

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