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Author Topic: Given the speed of evolution, how can one be certain that speciation does occur?  (Read 485 times)

Offline Irfan Samad

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Given the fact that speciation is an extremely slow process taking millions of years according to the theory of evolution that is hard to notice or observe in nature, how can one be certain that speciation does occur?
« Last Edit: 22/06/2016 08:06:23 by chris »


 

Offline puppypower

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One problem with answering this question is the cataloging of species is not consistent across the board. Lions and tigers are considered separate species yet they can reproduce. While humans from the same geographical areas are not considered separate species even if they look different. The cataloging of species began before we knew about evolution. Evolution had an impact, and changed further cataloging. Once we knew about DNA, that changed the way we catalog, but not all the past changed. Then, more recently, the catalog was impacted by social sciences and politics; PC. There is something for everyone, so there is always an explanation; rigged system. There has been no attempt to rewrite the catalog based on the latest science.

With humans, there are basic similarities within each race. Any human can tell the difference between African, Asian, Indian, Middle Eastern, European. Within each race, there is a wide variety of different looking people. Even within each family, there can differences between children and parents from height, weight, temperament, personality, intellect, muscularity, health.  Variations happen quickly and all the time, with humans, even child to child. There are seven foot humans and three foot humans. We could call these different species, if we wanted to, but PC has had an impact on cataloging. 

The question is how can you get so much variation in humans in such a short time span, when genetics takes so long according to evolution, to form stable species? Or why do humans vary so much when other species tend to be more uniform and easier to catalog with one standard?

Genetics can't be the full answer. I tend to think the brain and nervous system, which impacts cellular differentiation control, can tweak differential control, allowing new stable variations even in a family. Human have the strongest brains making variations, higher, while also allowing stable integrations. Although not all integration are stable and may lead to health problems.
« Last Edit: 22/06/2016 12:33:48 by puppypower »
 

Offline Semaphore

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Breeding can change species very rapidly. Your cute little Pekinese was bred from wolves, and all our domesticted animals came from their wild ancestors. That's all in a few thousand years. There was study done in domesticating foxes and by breeding the least aggressive animals, they got the same passive traits that we see in dogs, in just a few generations.

All it needs to create a new species is a niche environment. If some birds move to a new valley and the food sources there produce their fruit earlier or later, then the birds will change their mating habits accordingly and will no longer mate with their cousins. Evolution will then further separate the new species.

ETA: it's true that lions and tigers can breed, but their offspring is sterile.
« Last Edit: 23/06/2016 16:14:32 by Semaphore »
 

Offline evan_au

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Quote from: Irfan Samad
how can one be certain that speciation does occur?
Darwin collected finches on the various Galapagos Islands; Gould classified them as different species by the the different beak shapes, related to the different food they ate. They were separated into non-breeding groups by geography and diet - a process that does not take millions of years. He did not imply that they couldn't breed, just that they didn't breed. There are hints that with habitat changes, some hybrids of Darwin's finch species are appearing.

Today, with world-wide transport (accidental and intentional), the long-distance barriers between populations in different regions are breaking down.

But at the same time we are creating new micro-habitat islands due to expansion of cities. If these fragmentary habitats are big enough to prevent extinction, then we may see new local species appearing.

One speciation that is of interest to us humans is that of our nearest living relatives: The chimpanzees and bonobos.
Along with the common chimpanzee, the bonobo is the closest extant relative to humans. Because the two species are not proficient swimmers, the formation of the Congo River 1.52 million years ago possibly led to the speciation of the bonobo. Bonobos live south of the river, and thereby were separated from the ancestors of the common chimpanzee, which live north of the river.
 

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