Friday, October 29, 2010

Temperate Rain Forest Biome

Redwood national park, California
     Temperate rain forests vary throughout the world but because of their temperate latitude and high rainfall, the species that live there are remarkably similar in function and form.  The rain forest of North America's Pacific coast is the largest of the world's temperate rain forests.  It holds the most beautiful scenery I have ever seen and provides habitat for a bounty of wildlife.
Seen from Capilano Bridge, British Columbia
     The Pacific rain forest stretches along the coast in a relatively  narrow band from northern California to Southern Alaska.  The forest's most predominate plants are conifers including Spruce, Hemlock, Douglas Fir and the Giant Sequoia.  These conifers create a canopy cover in excess of 70 % and shade an understory of broad-leaf trees and shrubs. They do not need a fire event to regenerate but the Douglas fir does require a stand-clearing disturbance to establish a population of seedlings.  Other conifers germinate in shade or natural forest openings often making use of a fallen, decaying "nurse log" which provides the nutrients and moisture for germination.  They are well suited to the mean temperature of 4-12 degrees Celsius (39-54 degrees Fahrenheit).  They also thrive thanks to the 200-400 cm (79- 158 in) of annual precipitation which comes primarily as winter rain with snow at higher elevations and frequent fog near the coast and rivers.

Saturday, October 23, 2010

The Lake Seminole Reservoir Habitat (extra stuff I did just because I grew up near this lake)

A perfect day on Lake Seminole

     Lake Seminole’s 376 miles of shoreline borders a 37,500 acre man-made reservoir in the southwest corner of Georgia.  The lake boasts some of the best fishing in the southeastern U. S. with healthy populations of black, striped and hybrid bass, crappie, bream, shellcracker, and catfish.  Huge water lilies and other aquatic vegetation provide excellent cover for fish.  Duckweed presents a significant challenge on the lake.  It proliferates and chokes the channels so the Corp of Engineers uses herbicide and sterilized grass carp to keep the lake navigable.
Impressive comeback
      Over-harvesting in the past reduced alligator numbers to critical levels so they were a protected species for many years.  Their numbers have rebounded impressively and game regulations now allow for a few to be taken yearly during a closely regulated season.  Deer and waterfowl abound.  Birds of prey are the most unexpected residents on the lake.  Reintroduced about 20 years ago, Bald Eagles and Ospreys are not yet abundant but their nests are dotted about in the dead trees that rise from the lake bottom.
Jim Woodruff Dam made it happen in 1963
    The lake is backed up by Jim Woodruff dam at the confluence of the Chattahoochee and Flint Rivers and Spring Creek.  The lake borders Florida on the south.  The reservoir was created as a part of a much larger project to provide hydroelectric power and recreational areas for water skiers, campers, fishermen and hunters all along the lower half of the Chattahoochee River.  The abundant natural resources were enhanced by backing up the lake.  This area has been occupied by humans for at least 10,000 years.  An ancient Indian mound was hidden forever when the lake was backed up in 1963.

Orca: The Killer Whale Niche

Orca (Orcinus orca), more commonly called the killer whale, is the largest member of the dolphin family.  They live in groups called pods, usually led by a matriarch, and are found in all the worlds oceans from Arctic and Antarctic regions to tropical seas.  Orcas feed on a wide variety of prey items from bite-sized fish to marine mammals as large as gray whales.  There is even recent footage of an Orca killing a great white shark of the California coast.  Orca tend to exploit the most abundant prey in their habitat and develope specific strategies for catching it.  Killer whales visiting a seal colony in Pategonia actually beach themselves in order to catch seals pups.  Others hunt cooperatively to prey on sardines and salmon.  Their behaviors are taught to their young, creating a killer culture unique to each pod.

Friday, October 22, 2010

Mitochondrial Eve

     A 1988 Newsweek magazine offered this depiction of "Adam and Eve" which reflects humankind's evolution in central Africa.  This representation probably bears a little more resemblance to a typical modern African than the lady who is the topic of this blog, the real Mitochondrial Eve.  In reality, she probably stood around 5 feet tall with a medium brown complexion, course dark reddish- brown hair and dark eyes.
    As humans multiplied, populations began to fragment and venture out. Some groups remained in Africa as others crossed into the Middle East and beyond.  Populations became isolated as they began to fill different biological niches and this geographic isolation permitted cultural changes.  Simultaneously, natural selection was at work creating physical changes to better enable populations to cope with their new environments.  The result after a few million years is a myriad of diverse populations worldwide.
      Today, we live in a "global community".  Modern transportation, international trade and military activity are just a few of the factors that  bring these previously isolated communities into more frequent contact.  The result over time will likely be a return to less diversity in the appearance of the population although that may require several  thousand years.  After all, we didn't achieve this level of diversify overnight.  Humans also seem to have a nasty, innate need toward  feeling that their group is superior so I suspect  racism will probably die hard.  I hope we continue to evolve until that is no longer the case!
     The photos below represent just a small sample of the diversity in today's world.

Zulu warriors of South Africa (S. E. Africa)
Igbo or Ibo people of Nigeria (W. central Africa)
Inuit people of northern Canada

Japanese family from the Asian island of Japan

Nordic people of Scandinavia
Inca people of Peru