Chapter 10. Chapter 10: Evolution and Extinction
Why do some scientists say that we are currently...?
Guiding Question 10.3
Why do some scientists say that we are currently in the middle of the “sixth mass extinction"?
Why You Should Care
Species appear to be going extinct much faster than they did before the existence of humans. Based on estimations from the fossil record of how rapidly species died off in the mass extinctions, they may in fact be going extinct faster now than they did in some of the previous five. And we now have to estimate how many species are going extinct by extrapolating from an incomplete set of information since not all species are described and it is difficult to know when some species are truly gone. Should you be skeptical of the estimates? Not really, because, besides the scientific evidence, the fact that a pattern of rapid extinction is clear at all lends credibility to the pattern. Why does it matter if many species are going extinct if those species are flies or moss that probably live in some tropical wilderness? Extinction is permanent. When people die, all of their experiences, knowledge, and stories die with them. When species go extinct, all of the accumulated variation of generations of organisms is lost. Most societies consider human life sacred and the untimely loss of life a tragedy, even for the humblest of people, because, at the very least, it means the loss of potential. When species experience an untimely extinction, even if that species is a round worm, who knows what that species could have contributed to the ecosystem, humans, or the world?
Question Test Your Vocabulary
Choose the correct term for each of the following definitions:
| Term | Definition |
|---|---|
| nPm9U5MzneWEgAoNCx8smU2n7bOdHn6oaHaBJTmxxyiiaMIzBnp3mo1oN24F6lenRx0U7JB9/0PVOc0aei87YBPBW1tJFVWBDkktSMuB7d798WK23A7rT47xC+i8pO/BViupEJIRpRUXaT8LDdW6xq828SmHO0xrPXnWfSGuwBY= | Describes a species that is native to a particular area and is not naturally found elsewhere. |
| 9D98p7B6p/XyUBESfvWkRFC/AB1QM66aBdZ/aB7+j4KeJnSmBulH1K5SG8TaLN8xQd4JFOpIYdqMMGlvkYzj17xhGvheFHl1RE9/IwEr4xQqhUNKcG02QfkR9oxTjvgdqmzZ/A/il/4gJRRTDLRM3Im/sG3eWUxsFkyFYXpzzB8= | A species that faces a very high risk of extinction in the immediate future. |
| Nw3wR1UKT80B4yQcBPQ8zOq2r4pV70NkTksWzxAG6cWXLnJ80PZESIfJXzgN9ZEx72kYRDelHfdUPxE00P9YAyiPni2F1X+HXX5W1C1iGl2M6raljqm1VtA9nqi1ZR+gFmDEXzowt3/INglbvqMHWJuCfLv95/grUUKg/sDMto8= | Local extinction in one or more areas, though some individuals exist in other areas. |
| fHPnnHYQ0+7W0uV+DS0+X+xMTXfLgUYqRTDKKe5uqtrVg/DM3lSLX3X8BjHwY5UtbGC7I3smj/IV9LLLXKu9a8g/e0allVYaGWElKOtzO/IGczf+e8YBvlwqJ1If32vVrc2cbcEv6i9lgpVR40uLthwVyYWa8OirkLHIIqa0+WI= | A species that is likely to become endangered in the near future. |
| Sy4Xr/lobZK0ogplwAtRuQvzKugcifKcPXBGgxwJJzbxpS7mtS3YkkCU8xqajNG4bQb82Tm1W9YGk2ZtFXXQhA9F3EJ5vwUkHi1o8EOQh20HOhzsfciiZlmNd70eJ/4Qc8jafiP+2isicRVY8gpsOuRFMMUGs0t4ChrMlyEqonM= | The complete loss of a species from an area; may be local (gone from an area) or global (gone for good). |
| RAoE85g4ic/nnB3Qx30PGPpmkF6Nd9v54nJ83+14mbDyi8bIiY7lMZu5aAS9Wl3JQmPnFmTu+z8LqCjCg8pdFoz+kXUgZfKIFK5VTuw2GShlPoeiA2qtsDfOEgDrqAuq3GL2AFX73gbvbe/PQw01x8xn7D34bImdwSWm4dcu8ks= | The total collection of fossils (remains, impressions, traces of ancient organisms) found on Earth. |
| Q5Hj4qplPDjfethJJHsQmbFB/LKTTIafGPfjdRkAeToWDCEpYR6e6KDcKBStmFXgDwI9UcoVZmBc8giN60uNBYlvIjyDx9jzKJvOTogapluGf05XjRCllC4hm1Qkl3DVk4coS0uGAaaRoTi2fHtdSmDEDuQuwntkNe53ZiUlk3Y= | The average rate of extinction that occurred before the appearance of humans or that occurs outside of mass-extinction events. |
Question 10.1
Match the description to the mass extinction:
| Mass Extinction | Description |
|---|---|
| N+g/wc1lJKoDm3bGxSJBYLih1XyYoT7IC+hxCJDprGIlsKds6GAsBuXyMkCbxrZWAFEJ7XGoIVZOIjsY | Made room for dinosaurs to evolve. |
| /RVKX2WT+MNME3OeBRpYiGHnW5odDv0e857dARc6ej+2N0OvI/3U0JPmjx/F9uxD+R2UR76W8y0wmQma | The earliest known mass extinction. |
| eqO4RlpdGO7eHLwMBcgHyg0tn4UHJM9R9lKe+kUhj811n2x4LV4Ysy45xlUIvIyv9LXZ9rZ0+EOnFXwq | This second mass extinction preceded the Carboniferous period, which was when the plants that are now fossil fuels were growing. |
| J2JH0irNZZlG23D0OCZtKFfxwUOudwRHbAQmbkQ6b2779HT3e64nsDuLpTBcCvJMcBmojhe+pr7BUk5Z | The largest known mass extinction. |
| Iyt4S6qM6HL+AMypmM5FDe9MSTIqfvHjSRjq6FLntVeWsW81HaN368y4XtWNiTAI/fMWercHvyzDZz6A | The extinction event that killed the dinosaurs (except birds). |