Tanay Krishna12/13/20174th Period LoomisAPES”The Sixth Extinction” Book ReportSummary: “The Sixth Extinction” is an book that centers around the things that human beings are doing to the environment, and specifically argues that human beings are creating a “sixth extinction” on Earth as a result of their actions. The book is made up of thirteen chapters, each of which tackles a unique environmental issue. The book kicks off by speaking about what humans have done to frogs that live in Panama. The population of the Panamanian Golden Frog has recently dropped dramatically as a result of the introduction of an invasive fungus brought over by humans which has resulted in large-scale disturbances to the environment and has consequently resulted in a sudden drop in the frog population of the area. The book also notes extinction rates for frogs have often been connected with larger extinctions throughout Earth’s history.
The implication behind this data? If we do not change the way that we approach the concept of invasive species, we could cause lose far more species than we intend to. Kolbert also explains that catastrophes can be behind extinctions. In Chapter 2, she explains the impact of catastrophes by referencing George Cuvier’s study of the Mastodon. Theoretically, there was no real reason for the Mastodon to die out.
The mastodon’s traits, specifically its humongous size, should have allowed it to stay alive for a much longer amount of time than it did. Because of the fact that the organisms should have survived, but ultimately did not, Curvier concludes that natural disasters must have been the reason behind its extinction. Kolbert talks about the impact of catastrophe to show that human-created issues like climate change could cause more extinctions, as these are increasing the amount of natural disasters that occur each year. As we cause more of these issues, we undoubtedly will drive more species to their deaths.Chapter 3, the next chapter, takes a look at the Great Auk. The Great Auk was a large seabird that was hunted to extinction after sailors used it for feathers, oil, and meat.
Because of direct attacks by humans on the species, they died out. This chapter serves to show that humans have the power to drive species to extinction, something that we should never do in the future.In Chapter 4, the focus of the book switches and talks about the Cretaceous-Paleogene extinction. The extinction was caused by an asteroid that collided with earth.
However, the ecological impact that was made was not entirely caused by the asteroid. After impact, debris spread out across the world. Ammonites, a type of prehistoric organism that lived in the oceans, were not affected by the impact of the asteroid itself but by the humongous changes set in place by impact. As ash entered the sky and significant amounts of debris entered the hydrosphere, the ecosystem changed too drastically, and the ammonites were wiped out.The next two chapters speak about the importance of ocean chemistry, both in the scale of temperature and acidity. This issue is discussed largely because of the fact that people are polluting the oceans and the atmosphere, which change the chemistry of the oceans.
These changes happen due to greenhouse gases, which change the temperature of the ocean. On top of rising ocean temperatures, high concentrations of carbon dioxide also cause carbonic acid to form in the oceans, which lowers the pH, causing the oceans to become more acidic. Not only that, the book also speaks about the other ways we assault the oceans, like fertilizer runoff that leads to algal blooms, which result in dead zones. As if this all weren’t enough, we continue to blast carbon dioxide into the skies, and cut down the very trees that suck up the killer gas as we continue to deplete the earth’s forests. But the threat of carbon dioxide has a side that is talked about less than climate change: ocean acidification.The slow and gradual acidification of our oceans is costing us many key organisms, including coral, which depend on the ocean environment being a certain way in order to survive. Nowadays, the oceans require coral to use much more energy in order to calcify themselves, which causes the coral to die at a much higher rate, as they expend lots of energy on what should be a very simple process.
But the book doesn’t veer away from the issue of climate change. The very next chapter, Chapter 8, speaks extensively on the impact that climate change has on organisms who live in cold climates and therefore must be in such an environment to survive. These organisms oftentimes depend on the presence of ice, which is melting in humongous quantities.
Organisms like the polar bear are finding it increasingly hard to survive, and unfortunately, the situation appears to be moving in a direction in which only those that can live without ice will survive.In Chapter 9, the book switches topics. While the last few chapters focused on climate change and ocean acidification and their effects, the book veers into speaking about the impacts of isolation.
Extreme isolation can truly hit an area’s biodiversity, and cause species to become incredibly specialized to their environments because of the loss of gene flow or any large-scale changes to the environment. Chapter 10 speaks on the formation of a new “virtual Pangea.” Because of the actions of people, the moving of organisms throughout the world due to humans means that it is almost as though all continents are connected, because creatures can move between them.
This results in a variety of invasive species becoming prevalent across the globe, as previously discussed in the book. An example of the threat of invasive species is the American chestnut. Once the dominant tree across the Eastern United States, the tree has been more or less completely destroyed by chestnut blight.The next issue the book speaks on is habitat fragmentation, which doomed the Sumatran Rhino. Once bountiful, the rhino’s habitat was split into many small fractions due to human settlement, which made it difficult for the species to breed. Over time, this has resulted in the Sumatran Rhino almost going extinct, and remaining critically endangered.Finally, “breeding out” is the topic of the last chapter. Neanderthals were once common and probably would not have died out if human beings had not taken their place.
From here, the Neanderthals and humans bred, and over time, since there were more humans, Neanderthal genes became more and more diluted until the species was extinct. Reflection: I personally loved reading this book. It filled my head with knowledge and added more context and real-world examples to the concepts that we discuss in class. In particular, I enjoyed the example of the Great Auk. I see this species as a classic example of the power and subsequent responsibility that human beings have to protect the earth and its species. The Auk was wiped out within a few decades, and was used haphazardly and wastefully by sailors. We as a society need to make sure that we understand the kinds of impacts that our actions can have.
We also discussed the idea of humans needing to cut back on their power in order to help the environment often in class. This parallels the book, which gave me a clear and in-depth understanding of just how strong we as a species are, and what kinds of impacts we can have if we don’t control ourselves. The book also talks about how the increase in temperatures due to man-made climate change has caused effects on the habitat destruction of species living in polar regions, as well as the other effects this issue has, things like the acidification of oceans, which was an issue I had never deeply thought about until now. This was similar to what we did in class, as we learned about the many negative impacts of climate change, but the book gave me a vivid and angry feeling about the issue that I had never felt before. Overall, I thought this book gave a lot of context to the work we do in class, and I had a phenomenal time reading it.
