10 Million years ago

The intelligence of the African Forest

 

 

 

 

 

The climate is warmer than today, wetter in some areas and very dry in others with ice restricted to the poles.  The sea rises and falls at higher than current levels, up to 80 meters higher.  Life fills the planet.  Mammals, in particular, evolve rapidly, adapting to specific climates and habitats across the globe. (more)

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Mammals evolve for every habitat

 
Base map adapted from Ron Blakey DeepTimeMaps.com
Movement of continents
 

Measures 

 
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7.8 billion

2020 Population

415 parts per million

2020 CO2 concentration

14.9° C

2020 Average Temperature

22 cm above level in 1900

2020 Sea Level

Shaded area shows 

uncertainty,

Dotted line is model

Homo diverges from chimpanzees

Pliocene Warm Period 

CO2 concentration above current level

Increase in Arctic ice

Shift to more extreme climate oscillations

Millions of years

Tens of Millions of years

 

About 4-5 million years ago is the last time carbon dioxide levels are as high as today. The climate overall is stable without ice age cold although it still fluctuates with the cycles of earth’s orbit. In the warm periods temperatures are about 2-3°C higher than the present and sea levels about 10 meters above current levels.  Northern latitudes are warmest, by as much as 6°C and oceans hold permanent el nino-like heat.

 

In Africa complex social behavior and intelligence emerges in diverse species, including parrots, elephants and the many lineages of primates, which travel the forest as connoisseurs of its riches.  In this intellectually competitive world, the apes that would become humans and their cousins, chimpanzees, differentiate from the gorillas.  They are the first primates to hunt, and they develop hand gestures to communicate silently.  In the forest they climb easily through the 3-dimensional space of the tree canopy under a dappled dome of leaves.

 

 

On each continent, flora and fauna evolve in isolation since the breakup of Pangea about 150 million years ago.  Australia, South America and Madagascar remain separated far longer than other continents, developing entire families of animals unique to their locale.  This isolation also left plants and animals vulnerable when foreign species finally did enter, as when the isthmus of Panama formed 3 million years ago, allowing North American animals to walk south.

 

Over tens of millions of years, major evolutionary changes in large animals becomes apparent.  Although evolution can be observed at much shorter timescales, even days or weeks for microbes, and modifications such as the size of the beak of the finch observed by Darwin can happen in a few years.  But the evolutionary tree of familiar animals plays out over long time spans that encompass myriad genetic mutations that may or may not survive the selection pressures of competitive life in a changing world. 

 

References

Image: Composite of Adobe Stock images.  Parrots from photo by World Wildlife Fund and National Geographic

Map: MapLarge. (2018). "GlobalFloodMap.org,."   Retrieved 23 September 2018, 2018, from GlobalFloodMap.org,.

CO2: Pearson, P. N. and M. R. Palmer (2000). "Atmospheric carbon dioxide concentrations over the past 60 million years." Nature 406: 695-699. https://www.nature.com/articles/35021000

Stap, L. B., B. Boera, M. Ziegler, R. Bintan, L. J. Louren and R. S. W. van de Wala (2016). "CO2 over the past 5 million years: Continuous simulation and new δ11B-based proxy data." Earth and Planetary Science Letters

 439: 1-10.

Stap, L. B., R. S. W. van de Wal, B. De Boer, R. Bintanja and L. J. Lourens (2016 ). "The MMCO-EOT conundrum:Same benthic " Paleoceanography 31 1270–1282.

Temperature and Sea Level: James Hansen, M. S., Gary Russell, Pushker Kharecha (2013). "Climate sensitivity, sea level and atmospheric carbon dioxide." Philosophical Transactions of the Royal Society A: Mathematical, Physical, and Engineering Sciences 371(20120294).https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3785813/

Miller, K. G., M. A. Kominz, et al. (2005). "The Phanerozoic Record of Global Sea-Level Change." Science 310(5752): 1293-1298. https://www.researchgate.net/publication/7458328_The_Phanerozoic_Record_of_Global_Sea-Level_Change

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