The pit of my stomach

SUBHEAD: Avocados, papayas, mangoes and yucca should have gone extinct millions of years ago.

By Natashia Hakimi on 9 December 2013 for TruthDig.org -
(http://www.truthdig.com/eartotheground/item/avocados_shouldve_gone_extinct_millions_of_years_ago_20131209)


Image above: Painting of a family of ambelodon, a gomphothere proboscidean in midground, by Sam Matternes, 1964. From (http://rhamphotheca.tumblr.com/post/11197204477/the-gomphotheres-and-the-avocado-most-plants-bear).

The Gomphotheres and the Avocado
Most plants bear fruit so that animals can eat them and then disperse their seeds. Avocados, and a few other fruits, are too large (or rather have seeds too large) to be eaten and be dispersed by any animals that are extant (currently in existence). These large seeded fruits, that are found throughout the Americas, evolved along with the large mammals of the Pleistocene epoch (the “Pleistocene Megafauna”), like Gomphotheres, other proboscideans, and Giant Ground Sloths. These animals went extinct around 10,000 years ago, and the Avocados lost their chief dispersers. Many plants went extinct along with the megafauna, but some, like avocados, found new dispersers (like humans and slightly smaller mammals). The geographic range of many of the fruits that survived decreased greatly, but they managed to hold on. (From source of image above.)

Many don’t know that if it weren’t for homo sapiens’ avocado fetish, their favorite fruit would have been wiped off the face of the planet by now. It’s common knowledge that fruits spread their seed through animals’ digestive tracts, and avocados are no exception. In order for their seeds to be planted far enough from their “parent” tree, fruits depend on animals to eat them, and then leave their seeds elsewhere. 

However, avocados’ huge, lethal pits present a modern day problem for most animals since most can’t reach, chew or digest the massive brown seeds at the core of the creamy fruit. So how is it the delicious green fruits are still found in dishes all over the world?

According to writer Maria Popova on her blog Brain Pickings:

...apparently, avocados coevolved with ground sloths and were originally eaten by gomophotheres — elephant-like creatures that lived during the Miocene and Pliocene, between 12 million and 1.6 million years ago, who happily reaped the fruit with their hefty trunks, crunched them with their massive teeth, and passed the seeds comfortably through their oversized digestive tract.

The problem, of course, is that gomophotheres no longer roam the Earth — and yet avocados still exist.

 Popular science writer and evolutionary biology champion Connie Barlow writes:

Avocado’s strategy for propagation made a great deal of sense throughout the long life of its lineage — until the present moment. Even after thirteen thousand years, avocado is clueless that the great mammals are gone.

For the avocado, gomophotheres and ground sloths are still real possibilities. Pulp thieves like us reap the benefits. Homo Sapiens will continue to mold the traits of the few species of genus Persea it prefers.

Ultimately, however, wild breeds will devolve less grandiose fruits, or else follow their animal partners into extinction.

And avocados aren’t the only vegetation that have been around past their due date.

Apparently, mangoes, papayas and yucca are also evolutionary anachronisms that have survived natural selection thanks to humans’ hankering for them.

.