Message 34 of 67 (653399)
02-20-2012 4:46 PM
Reply to: Message 1 by CrytoGod
02-19-2012 6:25 PM
misinformation rather than reality
Hi CrytoGod, and welcome to the fray.
I'll just add a few points to the ones made by others concerning your misinformation:
|How come there is no ape species more human like than chimps or bonobos? |
There are many intermediate species that have become extinct through one of two processes: (1) they evolved into later species or (2) they were outcompeted by other species.
|Why is there such a huge gap? |
Measured by DNA the gap between chimps and humans is about 2%, and this is similar to the gap between horses and zebras and donkeys.
The gap between humans and chimps is similar to the gap between humans and bonobos. The gap between chimps and bonobos is also similar but not quite to the same degree, due to the evidence of there being a common ancestor to chimps and bonobos that is more recent than the common ancestor with humans.
The gap between chimps and humans is similar to the gap between chimps and neanderthals (and yes we have DNA evidence of neanderthals as well as for chimps and bonobos) and the gap between humans and neanderthals is similar to the gap between chimps and neanderthals, but again not to quite the same degree due to the evidence of there being a common ancestor to neanderthals and humans that is more recent than the common ancestor with chimps.
The differences in these genetic differences are not linear\additive, but more like the sides of a triangle (or quadrilateral when we include bonobos with chimps, neanderthals and humans).
There are scientists today that argue that chimps should be classified as hominids.
There are also elements in the DNA of chimps, bonobos, humans and neanderthals that show we all had a common ancestor. The DNA evidence also links us to a common ancestor with gorillas, other apes, other primates.
|You would expect to find living gradations of species leading up to human, right? |
Can you show how the theory of evolution would predict this?
Do you expect to see great great grandparents roaming the world? Their great great grandparents?
Evolution is the change in the frequency distribution and composition of hereditary traits within breeding populations from generation to generation, in response to ecological challenges and opportunities.
This necessarily means that evolution occurs over sequential generations. This predicts that intermediates would be found in ancestral populations rather than in current populations.
As an example we can look at part of the fossil record for Pelycodus:
A Smooth Fossil Transition: Pelycodus, a primate
Pelycodus was a tree-dwelling primate ...
The numbers down the left hand side indicate the depth (in feet) at which each group of fossils was found. As is usual in geology, the diagram gives the data for the deepest (oldest) fossils at the bottom, and the upper (youngest) fossils at the top. The diagram covers about five million years.
The numbers across the bottom are a measure of body size. Each horizontal line shows the range of sizes that were found at that depth. The dark part of each line shows the average value, and the standard deviation around the average.
The dashed lines show the overall trend. The species at the bottom is Pelycodus ralstoni, but at the top we find two species, Notharctus nunienus and Notharctus venticolus. The two species later became even more distinct, and the descendants of nunienus are now labeled as genus Smilodectes instead of genus Notharctus.
This shows the gradual evolution, the "gradations of species" leading, generation by generation, from Pelycodus ralstoni through the intermediate species Pelycodus trigonodus and Pelycodus jarrovii before reaching Notharctus nunienus and Notharctus venticolus.
It also shows a speciation event where one parent population (Pelycodus jarrovii ) divides into two reproductively independent daughter populations (Notharctus nunienus and Notharctus venticolus).
At any one time along those paths you would think you have a single species, and yet by the time you go from Pelycodus ralstoni to Pelycodus trigonodus you have sufficient differences that have accumulated that Pelycodus trigonodus appears different from Pelycodus ralstoni, and by the time you get to Pelycodus jarrovii there are additional differences that are now sufficient for Pelycodus jarrovii to appear different from Pelycodus trigonodus.
These differences are similar in quantitative measurements to the differences between Notharctus nunienus and Notharctus venticolus, which are each sufficiently different from Pelycodus jarrovii to appear different one from the other and from their parent population.
Evolution occurs within the breeding population, not within individuals: it is the accumulation of differences from parent to child over generations.
Your parents are an intermediate between you and your grandparents. You will understand why your parents are likely still living, but that your great great grandparents have likely died out, gone extinct along with other individuals of their generation.