PDS APES 8th Period 2009-10

Plate Tectonics and the Rock Cycle

http://www.merrittcartographic.co.uk/plate_tectonics.html

The theory of plate tectonics came about in the mid twentieth century after compiling centuries of speculation andcontemporary  oceanographic studies that suggested that the earth’s surface was actually made up of moblie plates of solid rock floating on a sea of liquid hot mantle that flows at a rate of inches per year.  This mantle operates like a convection cell with hotter liquid metal rising towards the surface and denser cool rock sinking down back towards the Earth’s core.  The floating rocks, or plates, each cover immense area on the Earth’s surface and fit together like a 20ish piece puzzle across the globe.  The most interesting part of the theory of plate tectonics is the area where two plates meet, or a plate boundary.  Due to the plate boundaries unstable and mobile nature, volcanoes and earthquake activity cluster around active boundaries, which are sometimes referred to as faults.  The most notorious of these active regions surrounds the Pacific Plate, the largest tectonic plate on Earth, is dubbed the “Ring of Fire”.  This is one of the most highly active areas on the earth and contains a plethura of subduction zones and oceanic trenches that contribute to massive earthquakes and tsunamies, as well as a multitude of active and inactive volcanoes.  The subduction zones, most of which are in the pacific off the coast of asia and North America, create deep abysses and ocean trenches.  The marianas trench, the deepest point on the Earth, is the subduction zone on the Western plate boundary of the Pacific Plate.

Plate tectonic activity

The Rock Cycle

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/boundaries.gif

The rock cycle is constantly in motion across the planet, and keeps recycling rock over eons through natural processes.

https://www.e-education.psu.edu/files/earth530/image/rock_cycle.gif

I am slightly confused on the differences between Keystone and Engineer Species.  Are they completely different, or is there overlapping?  Can an Engineer species be a Keystone Species, like the elephant?  Or is an engineer species automatically considered a keystone?  If anyone has any distinctions, categorizations, or knowledge that could help me out i would appreciate a comment.  Ill check back later tonight.

Friday was an exciting and fun filled day overcrowded with Population Biology: thestudy of  characteristics of populations.   Population Biology is broken down into five ways to describe populations:

1- Age Structure

2-Geographical Distribution

3-Size

4-Density

5-Growth Rates

These five categories are used to describe populations and create maps or charts filled with population related  numbers.  The age structure of a population of organisms is comprised of three different age groups.  Pre-Reproductive, Reproductive, and Post-Reproductive organisms comprise a population.  The three have interesting relationships and whether the population is young and about to boom or aging and about to decrease can aid in studying animals in the field.  You can also describe a population by it’s geographical distribution.  Geographical distribution has three means of occuring.  Random Distribution, Clumped Distribution, and Uniform Distribution.  The names are pretty self explanatory but here they go: Random is random, Clumpers are animals that live and grow in concentrated locations and rely on or utilize other members of the population for their success, and uniform distribution means that they are spread equally over the target region.  The size of a population and the changes that can occur to it can be measured by the equation (Births +Immigrants)-(Deaths + Emmigrants).   Population Density is generally described as the number of indivuals over area inhaited.  This can be a very important classification for population biologists.  Population Growth and the rates with which it occurs can also be mapped out.  There are two types of population growth, exponential and logistic.  Exponential growth occurs with an increase of a certain proportion to what is already there.  In a population sense, the exponential growth is a percent and as there are more organisms, the annual growth is more organisms than previous years but not a different annual growth rate.   Logistic change is when a population has reached the limits of its resouces, either through competition or reproduction, and at a fluxuation  If anyone has any questions or there are issues requiring more clarity i will try and check up on the blog over the next few days