The feature(s) that maximize variance and minimize reconstruction error are equivalent.

The result of PCA can be considered

Each Principal Component is a non-linear combination of a subset of the original dimensions

Each Principal Component is a linear combination of all of the original dimensions

Kelp forests: List, with brief explanations, four (4) ways that the role of kelp in the ocean ecosystem, i.e., effect on the ecosystem, is similar to the role of trees on land.  If you list structural similarities between kelp and trees, you must explain the roles/effects of those kelp structures in the ecosystem.

Deep-ocean trenches are the deepest parts of the ocean.  a) What are deep-ocean trenches?  How are they related to plate tectonics?  Be sure to explain in your own words. b) Name a deep-ocean trench and describe where it is located. Extra credit:  Why are trenches always deeper than the seafloor next to them?    Do not rely just on Figure 4-11 for this question.  Also see Figure 4-15.

Global warming and sea level: a) How has global warming caused global sea level to rise over the past century?  Explain 2 different mechanisms.  b) Where are the 2 regions of ice that could cause the largest global sea level rise if they melt?

Global climate models: Refer to Figure 12.23 in the chapter (or click to download it).  This figure shows “Components of global climate models and improvements to each over time.” a)  Why did global climate models start with the atmosphere?  (There are several good answers to this.) b)  Why is ocean carbon important to these models? c)  Constructing a model to simulate a highly complex system like Earth’s climate is a long, stepwise process.  This figure shows that scientists have been working on it for 50 years.  Consider a point in the process before the model is “complete” and “perfect”.  How would you decide whether the model is good enough to be useful?

Ocean in the climate system: a) Why is the ocean a dominant factor in the Earth’s climate system?  Give 4 global-scale reasons and for each one explain how the ocean affects climate. b) Which do you think is the most important, and why?

Longshore currents: a) Under what conditions do longshore currents form? b) Describe 2 ways in which rip currents are different from longshore currents.  Do not simply give definitions of each one.  Instead, explain how they are different.Rip currents are described in the second reading assignment: Segar page or Mpora page.