From the Museum of Paleontology
When you clicked on the bookmarks, which events were listed, and in what order?
The first event was the formation of the earth and the moon, which was estimated to have occurred 4,600,000,000 years ago. The second event marked the earliest life; this was believed to have happened 3,900,000,000 years ago. The third event showed the beginning of early land plants, which was predicted to have existed 420,000,000 years ago. In addition, the fourth event was mentioned as the largest mass extinction.
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This event is estimated to have occurred 248,000,000 years ago. The event is also referred to as the Permian extinction. Furthermore, the fifth event referred to the Dinosaur extinction, which is thought to have occurred 65,000,000 years ago. Finally, the sixth event was known as the discovery of the early hominid Lucy, this was dated to be 4,000,000 years ago (University of California, Berkeley, Museum of Paleontology, 2016).
In the Geologic Time Scale section, which images of organisms are included in the Archaean time period?
Archean period occurred between 2,500 and 3,800 million years ago. The images shown in the archean period include cyanobacteria and stromatolite. It is believed that single-celled organisms like bacteria started to evolve in this period (University of California, Berkeley, Museum of Paleontology, 2016).
Which three periods of time are described as Eras? List the representative organisms included in the photos that appear when you click on each Era
In the Phanerozoic period, three major changes were observed in biodiversity. These periods were called Eras in the geological time scale. The three periods referred to as eras are Cenozoic, Paleozoic, and Mesozoic. The three periods refer to ancient life, middle life, and recent life respectively (University of California, Berkeley, Museum of Paleontology, 2016).
In ancient life or the Paleozoic era, it is believed that most animals originated in this period. The organisms represented in the photos in this era are archaeocyathid, trilobite, brachiopod, progymnosperm, and blastoid (University of California, Berkeley, Museum of Paleontology, 2016).
In the middle life or Mesozoic era, there was an abundance of cycads, ferns, and dinosaurs. The organisms represented in the photos during the Mesozoic era are birds, conifers, dinosaurs, and cycads (University of California, Berkeley, Museum of Paleontology, 2016).
In the recent life or Cenozoic era, mammals, ray-finned fishes, flowering plants and birds became abundant. The organisms represented in the photos shown in this period include saber-toothed cat, megaceros, mammoth and flowering plants (University of California, Berkeley, Museum of Paleontology, 2016).
From the Sam Noble Museum Mass Extinctions, how many major mass extinction periods are listed here? Follow the links from that page to learn more about each period. What caused each, and which major groups of species disappeared from each period?
Sam Noble Museum Mass Extinctions provides five major mass extinction periods. The mass extinction periods mentioned are end-Ordovician, late Devonian, end-Permian, end-Triassic, and end-Cretaceous events (University of Oklahoma, 2016).
This was the oldest of the big five mass extinction events. Extinction was mainly confined to sea life because animals had not taken to land. It is estimated that it removed 85% of marine animals. The extinction was caused by climate change. Ice age caused cooling throughout the world. It occurred in two phases, the first during cooling and the second during the warming of the world after the great ice age. Species that became extinct included Trinucleidae, Thaerodonta, Bathyuridae, Climacograptidae, Diplograptidae, and plaesiomys (University of Oklahoma, 2016).
Late Devonian period
During the Devonian period, three mass extinctions were recorded. However, the last of the three, known as the Frasnian event was the most devastating of all. It occurred mainly in tropical environments, especially in the reefs of shallow seas. Climate change is thought to have contributed to this extinction due to the cooling of the global climate near the end of the Devonian period. It is also believed that limited carbon dioxide caused cooling. The affected species included Odontopleurid, Dalmanitid, Phacopid, Atrypid, and Pentamerid (University of Oklahoma, 2016).
Two extinction events were witnessed in this period. However, the last of the two was the most destructive. Global warming, which was associated with changes in oceans caused it. This was caused by the massive production of carbon dioxide from increased volcanic activity. Species that disappeared included Trilobites, Tabulate corals, and Rugose corals (University of Oklahoma, 2016).
Global warming near the end of the Triassic period also caused this extinction. Increased volcanic activity due to the breaking of the Pangea supercontinent introduced carbon into the atmosphere, which led to global warming. Species that were extinct included Brachiopods, corals, sponges, and shelled cephalopods. Moreover, land animals such as phytosaurs were destroyed (University of Oklahoma, 2016).
This extinction is much talked about because it gave an opportunity to mammals for their survival. It is believed that an asteroid of 10 kilometers in diameter crashed on earth. This caused dust to rise in the atmosphere, thereby blocking the sun’s rays. Eventually, this led to the extinction of plants because of reduced food production through photosynthesis. In addition, it is believed that global warming also caused extinction. Species affected included Ammonite, gryphaeid oyster, inoceramid, Pterosaurs, non-avian dinosaurs, and Mosasaurs (University of Oklahoma, 2016).
Choose two of the recent extinctions listed on this link and explain how they occurred
Moas extinction on Islands
It has been found that species on islands are usually vulnerable to extinction because they are small. Extinction happens because of human activities on islands such as hunting, the introduction of competitors or predators, and habitat alteration. For instance, in New Zealand, around 40% of forests were cleared by fire. In addition, dogs and rats were introduced into the environment. Alteration of habitat led to the extinction of moas. Other species threatened due to the existence of people in New Zealand included Tuataras and kakapos (Gerstein, 2015).
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Overexploitation of Sea Cow
Overexploitation of the earth’s biosphere led to past extinction. Moreover, further overexploitation will lead to more extinction in the future. Some of the species that have become extinct due to overexploitation include Steller’s sea cow from Eastern Russia. the sea cow was discovered in 1741 and it became extinct in 1768. Past records show that Russians hunted more sea cows than they could eat using harpoons (Gerstein, 2015). The other species, which was hunted in large numbers, was the passenger pigeon, which was overexploited in the U.S. and Southeastern Canada.
Review tutorial on the carbon cycle and greenhouse gases
What was listed as human activities related to greenhouse gas production? What does this do to the rate at which carbon is returned to the atmosphere?
Human activities listed include overexploitation, alteration of habitat, and industrialization (Denkabe, Pessey & Saeed, 2016). These activities can lead to the release of greenhouse gases, especially carbon dioxide that increases the temperature of the world (Cummings, 2016).
When you click on the graph menu, what is the relationship between Percent (%) of greenhouse gases and temperature? What is the relationship between temperature and ice? Which mass extinction from the Natural History Museum website in part I does this remind you of?
The percentage increase in greenhouse gases leads to an increase in temperature change. In particular, the percentage increase in gases goes to over 200% as temperature change increases to more than 6 degrees Celsius. Additionally, as temperature change increases to 6 degrees Celsius, the percentage of ice decreases to 25% of the current. Therefore, as ice increases, temperature decreases, and as ice decreases, temperature increases (Biogeosphere- Atmosphere Stable Isotope Network [BASIN], 2016). This reminds us of the end-Permian extinction period because it happened due to global warming (Cummings, 2016).
What role does human activity play in the current global warming trend?
Human activities contribute to more production of greenhouse gases in the atmosphere, especially carbon dioxide. Carbon dioxide contributes to global warming (Cummings, 2016).
It can be observed from the case studies above that climate change has contributed to most of the extinctions in the past. In this regard, the current climate change has the ability to cause future extinctions. Therefore, more studies should be done to establish the effects of climate change on the inhabitants of the world, especially the most vulnerable species.
Biogeosphere- Atmosphere Stable Isotope Network [BASIN] (2016). Tutorial: how are isotopes used to understand the global carbon cycle? Web.
Cummings, B. (2016). Greenhouse gas simulation pearson learning solutions: The greenhouse effect. Web.
Denkabe, A., Pessey, D., & Saeed, A. (2016). Tutorial for community climate change awareness project. Web.
Gerstein, J. (2015). Recent extinctions 11 extinct animals we’ve lost in our lifetime. Web.
University of California, Berkeley, Museum of Paleontology (2016). Geologic time. Web.
University of Oklahoma (2016). Sam noble museums: mass extinctions. Web.