86.
[Main Idea] Present the primitive marine species survived the extinctions and the study of three groups. The K/T extinctions need long time to recover. But since the change does not happen suddenly, so the loss of species diversity was not that much.
[Structure] P1: Primitive marine species survived the extinction: 3 groups P2: K/T extinctions resulted in evolutionary disaster P3: The Species’ demise were not sudden nor catastrophic P4: The effect of K/T extinctions was not that strong
[Each Paragraph] P1: The smaller, more generalized, or primitive forms of marine species survived the extinction. - Groups 1: The primitive forms moved from cooler water and high latitudes toward the equator to take place off the tropical species.
- Groups 2: The groups with good fossil records: tropics — younger; higher latitudes — ancient.
- Groups 3: The fossil history of these groups is not well known: higher latitudes — primitive.
P2: The K/T extinctions caused an ecological vacuum, and the process of recover takes long time. P3: The fossils showed that extinctions in major groups of animals began before the K/T boundary and took a long time. The pelagic plankton species’ change took a shorter time, but not sudden nor catastrophic. P4: The effect of the K/T extinctions has been exaggerated. Recent estimates have no scientific basis. The loss of species diversity is much less.
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发表于 2022-8-26 13:10:27
