Mitochondrial Eve

Mitochondrial Eve refers to the matrilineal MRCA (most recent common ancestor). She is the woman from whom all living humans today descend, on their mother's side, and through the mothers of those mothers and so on. This goes all the way back until all lines converge on one person. One hundred percent of mitochondrial DNA (mtDNA) comes from the mother. Mitochondrial DNA is separate from regular DNA. Your mitochondrial DNA is identical to your mother, grandmother. great-grandmother, and so on, tracing back to mitochondrial eve's.

Mitochondrial Eve is estimated to have lived around 200,000 years ago, most likely in East Africa. The same mtDNA is found in the 5 main populations of the world: Africa, Asia, Europe, Australia, and New Guinea.

African runway model Alek Wek

Asian film star Jet Li

European soccer star David Beckham

Australian singer Kylie Minogue

The famous Papuan people of Papua New Guinea

Lab 9: Dog Parks

 

Dog Park in Macon, GA

Dog parks are facilities set aside for dogs to exercise and play off-leash in a controlled environment under the supervision of their owners. Though parks may vary, a typical dog park offers a 4 to 6 ft fence; double-gated entry and exit points; adequate drainage; benches for humans; shade for hot days; close parking; water fountains (for humans and dogs); tools to pick up and dispose of animal waste; and regular maintenance and cleaning of the grounds.

Advantages
There are many advantages to taking your dog to a dog park.
(1) Dog Socialization Advantages
    - Dog parks provide an excellent source of dog-to-dog social interaction as well as dog-to-people     social interaction.
(2) People Socialization Advantages
    - Dog parks provide an excellent source of people-to-people social interaction. Dog-oriented people can meet and interaction, and from this doggy play dates can be arranged.
(3) Physical and Mental Stimulation Advantages
    - Dog parks provide an excellent source of off-leash exercise for active dogs. They allow dogs to get adequate physical and mental exercise, thereby lessening destructive and annoying behaviors in general which can benefit society as a whole.
(4) Educational Advantages
    - Dog parks provide a good opportunity for owners to learn about dogs through observation and provides the opportunity to learn from more experienced owners. It also allows for well-mannered-dog advocates to demonstrate how they turned their dog into a well-mannered dog.
(5) Community Advantages
    - Dog parks which are designed for dogs only lessen the chance of owners letting their dogs off-leash in on-leash parks.
    - No cars, skateboarders, bikes, etc. likely to be encountered
    - More likely to encounter people who enjoy dogs
    - Could provide a location for community dog activities

Disadvantages
(1) For People
    - Potential of danger from aggressive dogs
    - Potential of danger of physical injury from dog-related hazards
    - Potential of lawsuits arising from dog fights
    - Potential for parasites
(2) For Dogs
    - Potential of danger from aggressive dogs
    - Intact dogs may create problems
    - Potential for parasites and disease
    - Potential for lack of impulse control and over-excitement
    - Not appropriate for small and large dogs at the same time
    - Potential for injury
(3) For the Community
    - Some people will not understand the concept and will abuse the park by not picking up after their dog, leaving their dog unattended, or allowing their dog to indulge in inappropriate behavior
    - Some people will not be educated enough about their dogs to know if a dog park is appropriate for their dog
    - Potential for noise
    - Potential liability issues

Lab 8: Darwin's Dilemma

One of the most spectacular events in the history of life is the Cambrian explosion, which is also one the great mysteries of science. This was a moment of geological time when complex animals first appeared on earth fully formed, without evidence of any evolutionary ancestors. Charles Darwin viewed this as an inexplicable mystery. He envisioned the evolution of life through a multitude of small, undirected steps. Yet, the fossil record reveals no such pattern of gradual development. Instead, early in the Cambrian period compound eyes, articulated limbs, sophisticated sensory organs, and skeletons burst into existence seemingly out of nowhere.

Hallucigenia

The fossils of the Burgess Shale, more than half a billion years old, preserve an intriguing glimpse of early life on Earth. These fossils merit special interest for several reasons: they were buried in an underwater avalanche of fine mud that preserved exceptionally fine details of the structure of their soft parts. Only hard parts are preserved in most other Cambrian deposits, limiting information within the geologic record; they represent an early snapshot of the complexity of evolving life systems. The Burgess Shale fossils as a group have already developed into a variety of sizes and shapes from the much simpler, pre-Cambrian life forms; many of them appear to be early ancestors of higher forms - from algae to the chordates (a major group of animals that includes human primates). Other appear unrelated to any living forms and their later disappearance presents an intriguing mystery.

The Burgess Shale Site 510 Million Years Ago

From this picture it is easy to imagine how an avalanche of fine mud sliding down from the submerged reef top would have carried off any animals living in the shallow reef waters above. This avalanche could have caught some animals in mid-water and certainly would have overwhelmed and buried any creatures living at its base. The hard parts of all these animals caught in the mudslide were preserved as fossils, like the process at any other Cambrian site. However, here the fine mud also penetrated and filled all available spaces and crevices within the animals, thus preserving the shapes and locations of all the soft parts. 

A very busy place!

Cambrian Map

Take a careful look at this world map. Does China (3) lie due north of Africa? Is China really that small!? Why is Africa northeast of Europe? When is Europe way below the equator, two-thirds of the way to the South Pole? According to current interpretations of the paleogeographic record this is how the continental blocks were arranged about one-half billion years ago - before plate tectonics (which are still active) rearranged them into today's familiar positions.

Amphioxus

Lancelet, also known as amphioxus, is said to be the most primitive example of a vertebrate.

Lancelets are the modern representatives of the subphylum Cephalochordata. They are usually found buried in sand in shallow parts of temperate or tropical seas. In Asia, they are harvested commercially as food for humans and domesticated animals. Cephalochordates are small, eel-like unprepossessing animals. The reason lancelets hold such importance in the study of zoology is because of their remarkable morphology, providing an understanding of the morphology and evolution of chordates, including vertebrates.

Below is an external and internal view of the amphioxus cephalochordate. Cephalochordates have all the typical chordate features. The dorsal nerve cord is supported by a muscularized rod called the notocord. the pharynx is perforated by over 100 pharyngal slits, or "gill slits," which are used to strain food particles out of the water. The musculature of the body is divided up into V-shaped blocks called myomeres. There is also a post-anal tail. All of the above named features are shared with vertebrates. Arguably, there are features that vertebrates have that cephalochordates lack: the brain and sense organss are poorly developed in the amphioxus, and there is true vertebrae in the organism as well.

The fossil record of cephalochordates is extremely sparse because they have no hard parts. However, fossil cephalochordates have been found in very old rocks, predating the origin of the vertebrates. The fossils show that the chordate lineage appeared very early in the known history of the animal kingdom, and they strengthen the case for an origin of true vertebrates from a cephalochordate-like ancestor. 

Check out this video on Chordate Evolution!

Mystery of the Megafloods

On one of our lab days, we watched an informational filmed called the Mystery of the Megafloods. The film began by defining what a geologist is, stating that it is similar to a detective looking for clues in a crime scene. A geologist looks at the rocks for clues in history.

The primary question that was evaluated in the film was what caused the bizarre landscape in the Montana region (the scad lands). It took us through the thought process of those scientists trying to figure out the cause.Some of the possible causes included gradual erosion caused by rivers and a giant river flooded over and over again. These were later ruled out because of the enormous potholes.
The last ice age was approximately 20,000 years ago. Another hypothesis was that the glaciers melted, causing a great flood. This, too, was soon ruled out because the ice was too remote.
The next hypothesis was that it was been the result of an enormous catastrophe, perhaps a giant flood. This was thrown out too.
The geologists had trouble determining the cause of the bizarre landscape because they were looking at eye view. No one thought to look from a different perspective until aerial photos were shown. The photos revealed giant ripples in the earth, ripples that resembled those in the sand at the beach.

The next hypothesis was that a glacier dammed the lake, forming the ripples. Glacial Lake Missoula formed as the Cordilleran Ice Sheet dammed the Clark Fork River just as it entered Idaho. The rising water behind the glacial dam weakened it until water burst through in a catastrophic flood that raced across Idaho, Oregon, and Washington toward the Pacific Ocean. This was the cause of the bizarre landscape.

For more information on the flooding of Glacial Lake Missoula and how the flooding occurred, click here.

Lab 7: Hitchiti Experimental Forest

Hitchiti is a 5000 acre forest located in Jones County, GA. It is the site of the Brender Demonstration Forest, a cooperative effort by the Southern Research Station and the Georgia Forestry Commission to showcase pine management for nonindustrial private landowners. Hitchiti is a part of the Oconee National Forest and was established on 17 September 1938.

Our class at Hitchiti Experimental Forest!

I thoroughly enjoyed our trip to Hitchiti. We hiked over a mile through the forest, identifying different trees and plants that we learned about earlier in the semester along the way.

Asarum Canadense - Wild Ginger

One plant that we came across on our hike was wild ginger. Asarum canadense (Western wild ginger) is native to rich moist forests of North America. In the spring, it develops distinct hairy cup-shaped brown-purple to green-yellow flowers which terminate in three long curved lobes, often concealed by leaves. The long rhizomes give rise to persistent kidney/heart shaped leaves. Leaves are found in colonies or clusters (as depicted in the photo above). The leaves emit a ginger aroma when rubbed.

Sassafras

One tree that we came across on our hike was Sassafras. Sassafras is a genus of three extant and one extinct species of deciduous tress in the family Lauraceae, native to eastern North America and eastern Asia. Sassafras trees grow from 30-59 feet tall. The trunk grows from 28-59 inches in diameter with many slender branches, and smooth, orange-brown bark. All parts of the plant are very fragrant. The species are unusual in having three distinct leaf patterns on the same plant: unilobed oval, bilobed (mitten-shaped), and trilobed (three pronged).

Factoid: The largest Sassafras tree in the United States is located in Owensboro, Kentucky, which measures over 100 feet high and 21 feet in circumference.
Factoid: The name "Sassafras," applied by the botanist Nicolas Monardes in the 16th Century, is said to be a corruption of the Spanish word for saxifrage.

This is me hugging my very first tree at Hitchiti Experimental Forest!

Lab 6: Jackson Springs Park

On this particular lab day, we visited Jackson Springs Park. It is located off of Nottingham Drive in Macon, GA. It is in walking distance to the newly implemented Ocmulgee River Walk.

Here we were able to get hands on experience / learning with some of the different types of rocks. Our professor provided us with pick mattocks to break open the rocks that lined the creek. We mainly saw granite rocks, where we were able to identify hornblende, feldspar, and quartz.

We found a tunnel at one end of the park, which was kind of creepy but cool at the same time. On the rocks near the tunnel we were able to identify bits of mica.

Jackson Springs is a small but rather quaint park! The slow running creek adds a relaxation element which is always enjoyable.