Posted on 06/18/2016 3:05:57 PM PDT by SunkenCiv
It's called the latitudinal diversity gradient, a phenomenon seen today in most plant and animal species around the world: Biodiversity decreases from the equator to higher latitudes. A new study of fossils representing 63 million of the past 65 million years reveals that -- for North American mammals, at least -- the modern LDG is the exception rather than the rule.
The findings, reported in the Proceedings of the National Academy of Sciences, point to the importance of not assuming that the way things are today is the way they've always been, the researchers say...
It may seem obvious that more species can thrive in the relative warmth of lower latitudes, but that intuition about biodiversity may not always have been true, Marcot said. A warming planet does not necessarily lead to more diversity everywhere on the planet. It could just as easily lead to an expansion, or shifting, of individual species' ranges, with no corresponding increase in the overall number of species, he said...
A 2011 study by Marcot, Fox and other colleagues looked at fossils of mammals from many latitudes in western North America between 58 million and 63 million years ago. As in the current study, they used the Paleobiology Database for information about the fossils, the latitudes at which they were found and their ages...
That study found no evidence of a latitudinal diversity gradient for North American mammals at that time, only a few million years after the extinction of nonavian dinosaurs...
(Excerpt) Read more at eurekalert.org ...
In a study of fossils spanning 63 million years, University of Illinois animal biology professor Jonathan Marcot and his colleagues found that current patterns of mammal biodiversity in North America are a relatively recent phenomenon. [Credit: Photo by L. Brian Stauffer]
"I think he did a little too much LDG."
“Latitudinal Diversity Gradient — “latitudinal” meaning how far north or south of the equator, “diversity” meaning the number of species, and “gradient” meaning the transition between high and low. We’ll just call this mouthful the LDG for short. “
It’s pretty obvious that global cooling caused the diversity gradient, but we can’t say that.
Liberals are the part of science right? So... Mammals are all different. BUT, we humans are all exactly the same. There are ZERO genetic differences. Right? Heck, you can even change your gender regardless if you have XX or XY chromosomes.
What this article is saying that the Latitudinal Diversity Gradient does not have a constant slope.
There are changes in North America where the curve flattens and creates a zone, specifically the North America Latitudinal Diversity Zone.
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