Alycia Stigall's Research

Mary Strickland was born in 1839, Bowenfels along the Billabong Creek and was the daughter of Pierce and Letitia Strickland. Pierce Strickland whose mother was Mary Strickland who had been the lady who administered first aid to Ben Hall, when as a youth had severely broke his leg in the mid-1850's. Peirce Strickland was part of the Strickland family who controlled large stations, the most well known being Bundaburrah Station on the Lachlan Plains, and one in which Ben Hall had a close association with for most of his life. During her childhood and into early womanhood young Mary Strickland was raised in the company of the hard men of the Lachlan plains and the many stockmen and laborers working for her father and from this company had the friendship

The author and his colleagues specifically chose to focus on 375 million year old rocks in their search for fossils because this was the time frame that provided fish that would be useful to study from. The 385 million year old rocks provided fish that look too similar to the ones we have now and the 365 million year old rocks have fossils that don’t resemble fish. The 375 million year old rocks, however, provide fossils that show the transition between fish and land living animals.

8. The periods in which there were mass extinctions are Permian – volcanic eruptions which spewed lava and put CO2 into the air which warmed the climate an estimated 6 degrees Celsius. The resulting of oxygen deficiency. And Cretaceous – asteroid or comet

The author and his colleagues chose to focus on 375 million year old rocks in their search for fossils because amphibians that look dissimilar to fish were discovered in 365 million year old rocks, while fish without amphibian characteristics were discovered in 385 million year old rocks. Thus, it is possible that the evolutionary intermediary, or the “missing link” between fish and amphibians, would be discovered in 375 million year old rocks, between the two time periods. The rocks examined were sedimentary in composition, as the gradual and relatively gentle formation of sedimentary rock under conditions of mild pressure and low heat are conducive to the fossilization of animal remains. Sedimentary rock is also often formed in rivers and seas, where animals are likely to live. This site provides a resource that describes means by which fossils are formed and how the fossil record may be interpreted, and shows some examples of fossils demonstrating evolution through geological periods: http://www.fossilmuseum.net/fossilrecord.htm. In 2004, Shubin and his colleagues were looking for fossils on Ellesmere Island, in northern Canada. This location was chosen because of its lack of human development, as well as of obstructing natural formations and life forms such as trees, which

“A minority disputes this theory, arguing that other events-such as volcanic eruptions, sea-level changes or a series of impacts-were to blame for the spectacular loss of species that occurred at the transition between the Cretaceous and Tertiary periods…”

Anadromous salmonids, which travel between freshwater and saltwater, is an example of how habitat loss can change evolutionary patterns. Dams constructed for hydroelectric power generation are blocking the access for these fishes, but culverts and river engineering have also reduced the amount of habitat that anadromous fishes can use (Furniss et al. 1991; NRC 1996). These results suggest that loss of habitat will alter evolutionary patterns in salmonid populations.

Dinosaurs ruled the earth for over 65 million years and thankfully for the human race, they became extinct. Ultimately, only a major catastrophe could completely wipe out an entire species, let alone an entity of dinosaurs and the debacle on the causes of dinosaur extinction have flooded the minds of paleontologists for centuries. Geologist and zoologist Stephen Jay Gould published “Sex, Drugs, Disasters, and the Extinction of Dinosaurs,” to compare scientific and speculative causes of dinosaur decimation. Personally, I found this passage very informational and enjoyed reading it. Gould provides three theories that capture the reader’s curiosity, allowing room for pondering in one’s mind.

Assess the different hypotheses put forward for the mass extinctions at the end of the Permian and Cretaceous (KT) Periods.

<b>Introduction</b><br>Think of a world which existed 290 million years ago. As you look out over the terane in front of you, you think that you are on an alien planet. You see volcanoes spewing ash and lava. Beside them is the ocean which is swarming with many different species of echinoderms, bryozoans and brachiopods. As you look down onto the sea floor you are amazed at the countless number of starfish and urchins. Some animals leave you can't even describe and you have no idea even what phylum they belong to. This is a world at its height in diversity of oceanic species. Millions of wonderous species existed at this time in the ocean and most of them will never appear again in earth's history. In the geologic time scale, a million

Most critically threatened is the Mexican axolotl, A. mexicanum, a species endemic to the Xochimilco lake system, which is now reduced to an area only 1% of its historical size (Fox, 1965). Recent surveys show that the remaining population decreased substantially due to overexploitation, introduced species and habitat modification (Zambrano et al., 2007). Long-term isolation and reduction in population size leads to genetic erosion (O’Grady et al., 2006; Vilas et al., 2006), but the magnitude of these effects depends necessarily on the ancestral genetic composition of the species (G. Parra-Olea1 , K. R. Zamudio2 , E. Recuero3 , X. Aguilar-Miguel4 , D. Huacuz5 & L.

The Permian (alongside the Paleozoic) finished with the Permian– Triassic annihilation occasion, the biggest mass eradication in Earth's history, in which almost 90% of marine species and 70% of earthbound species kicked the bucket out. It would bring great into the Triassic for life to recoup from this catastrophe. Recuperation from the Permian– Triassic termination occasion was extended; ashore, biological communities took 30 million years to recover.

Ever since the history of Earth has been studied using fossil records, extinctions have always been the object of fascination and interest, particularly the mass extinctions that occurred throughout Earth's history. A mass extinction can be caused by disruptive global environmental changes, where large numbers of species have become extinct (Urry et al. 2008). There have been five major extinctions documented based on fossil records over the past 500 million years, but the Cretaceous (KT boundary extinction – a name that meant it began the Tertiary era) extinction caught a lot of

These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils.

Jurassic is a period of time with Dinosaurs, rodents and birds. There were also island seas consisting of sharks, sea monsters and blood-red planktons. The existing plants in that period were cycads, ferns and conifers. The Mesozoic era was about 245 million years ago to 65 years ago, so it almost lasted about 180 years in total. The Mesozoic era is divided into three periods of Triassic, Jurassic and Cretaceous. Mesozoic era means middle animals and it is the era, which the word’s fauna has changed from what is in the Paleozoic era and the most famous organisms of this era are dinosaurs. In the Mesozoic era, the extinction of more than 90 percent of species in the earth was observed and the reason behind it was mostly volcanic eruptions and climate changes. On the other hand, this era had massive changes that represented ecological niches and rise to new creatures such as rodent-size mammals and first dinosaurs. In Triassic, which was the first period of Mesozoic, the mammals and first dinosaurs existed. Later than that, the second period was Jurassic, which giant shaped dinosaurs and other kinds of dinosaurs were developed. Besides that the first flowering plants and primitive birds, with long teeth appeared in that era as well.

The patterns of biological diversity in rivers and streams among taxa vary on a spatial and temporal scale (Ligeiro et al. 2010; McGarvey and Terra 2015). Variations in stream ecology can be contributed to water quality, habitat, and history of disturbance (Lingeiro et al. 2010). Creeks and streams feed into rivers and other larger bodies of water, which provide food, water, and other commercial and recreational services as well as a home to an array of plants and animals which rely on clean water. The health of these smaller bodies of water can act as indicators for the health of the larger watershed.