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Pollen question

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Pollen question

Postby popgen » Wed Jun 08, 2005 1:04 am

I have a few questions that I cannot answer, Id appreciate some assistance.

8. In a core sample taken, pollen grain concentrations showed a progression from spruce and fir trees to pine, deciduous trees and grasses, to grasses and deciduous trees over the last 11 000 years. The probable reason for this reverse succession would probably be:
A. a disease of conifers.
B. the area getting warmer and drier over time.
C. forest fires.
D. destruction of evergreens by herbivores.

Explain WHY succession proceeds in a series of stages

. In a paragraph, interpret the meaning of the following statement: "Actual population size represents a compromise between biotic potential and environmental resistance."

THANKS
** Edited by thank.darwin - See rule #4**
<A post containing "anyone?" is deleted. It makes no sense.>
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Postby mith » Thu Jun 09, 2005 5:49 pm

hmm, why is the first post #8?
anyway the answer should be in your ecology notes.

Let's look at the problem first.

The problem states that there's been a change in pollen. Now since the plants don't really change their pollen production much from year to year, we can conclude that pollen production is an effect of something else such as perhaps something that eats specific pollens? Or more simply, the numbers are declining. Note the question only asks about the reverse portion of this trend.

So what would cause a decrease in deciduous trees? Well, herbivores could have run through the area and eaten everything(locusts maybe?). The trees could have died out due to disease. A forest fire could have wiped out the tree population but left the seeds intact. Warmer and dryer weather might kill off trees/grasses.

Conceivably it could be any of the choices.
Living one day at a time;
Enjoying one moment at a time;
Accepting hardships as the pathway to peace;
~Niebuhr
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