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BIO 1, Chapter 1; Biology and the Tree of Life

Terms in this set (16)

1. How did Anton van Leeuwenhoek make an important contribution to the development of the Cell Theory?
d. He invented more powerful microscopes and was the first to describe the diversity of cells.
2. What does it mean to say that experimental conditions are controlled?
d. All physical conditions except for one are identical for all groups tested.
3. The term evolution means that______change through time.
populations
4. What does it mean to say that a characteristic of an organism is heritable?
b. The characteristic can be passed on to offspring.
5. In biology, to what does the term fitness refer?
An individual's ability to survive and reproduce.
6. Could both the food competition hypothesis and the sexual competition hypothesis explain why giraffes have long necks? Why or why not?
c. Yes. Long necks could be advantageous for more than one reason.
7. What would researchers have to demonstrate to convince you that they had discovered life on another planet?
That the entity they discovered replicates, processes information, acquires and uses energy, is cellular, and that its populations evolve.
8. What did Linnaeus's system of naming organisms ensure?
a.
9. What does it mean to say that a species is adapted to a particular habitat?
Over time, traits that increased the fitness of individuals in this habitat became increasingly frequent in the population.
10. Explain how selection occurs during natural selection. What is selected, and why?
Individuals with certain traits are selected, in the sense that they produce the most offspring.
11. Is the logic of these two statements sound?
Yes. If evolution is defined as "change in the characteristics of a population over time," then those organisms that are most closely related should have experienced less change over time. On a phylogenetic tree, species with substantially similar rRNA sequences would be diagrammed with a closer common ancestor - one that had the sequences they inherited - than the ancestors shared between species with dissimilar rRNA sequences.
12. Explain why researchers formulate a null hypothesis in addition to a hypothesis when designing an experimental study.
A null hypothesis specifies what a researcher should observe when the hypothesis being tested isn't correct.
13. Explain the difference between a scientific theory and the everyday use of the word theory by using the cell theory and theory of evolution as examples.
A scientific theory is not a guess - it is an idea whose validity can be tested with data (a set of propositions that defines and explains some aspects of the world). Both the cell theory and the theory of evolution have been validated by large bodies of observational and experimental data.
14. From which structure did eukaryotes originate? Bacteria, Archaea, or Eukarya?
If all eukaryotes living today have a nucleus than its logical to conclude that the nucleus arose in a common ancestor of all EUKARYOTES. If it had arisen in a common ancestor of bacteria or archaea, than species in those groups would have had to lose a trait...an unlikely event.
15. Why was it reasonable to conclude that the cell theory was valid, when it could not be proven correct in the sense of providing incontrovertible evidence that all organisms are made up of cells? They could only state that all organisms examined to date were made of cells.
The data set was so large and diverse that it was no longer reasonable to argue than non cellular life forms would be discovered.
16. In areas of the world where HIV infection rates are high, are human populations evolving? Explain.
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