How Do We Know That Evolution Has Occurred?

The evidence for evolution has primarily come from four sources:

1.	the fossil record of change in earlier species
2.	the chemical and anatomical similarities of related life forms
3.	the geographic distribution of related species
4.	the recorded genetic changes in living organisms over many generations

The Catholic Position

What is the Catholic position concerning belief or unbelief in evolution? The question may never be finally settled, but there are definite parameters to what is acceptable Catholic belief. 

Concerning cosmological evolution, the Church has infallibly defined that the universe was specially created out of nothing. Vatican I solemnly defined that everyone must "confess the world and all things which are contained in it, both spiritual and material, as regards their whole substance, have been produced by God from nothing" (Canons on God the Creator of All Things, canon 5). 

The Church does not have an official position on whether the stars, nebulae, and planets we see today were created at that time or whether they developed over time (for example, in the aftermath of the Big Bang that modern cosmologists discuss). However, the Church would maintain that, if the stars and planets did develop over time, this still ultimately must be attributed to God and his plan, for Scripture records: "By the word of the Lord the heavens were made, and all their host [stars, nebulae, planets] by the breath of his mouth" (Ps. 33:6). 

Concerning biological evolution, the Church does not have an official position on whether various life forms developed over the course of time. However, it says that, if they did develop, then they did so under the impetus and guidance of God, and their ultimate creation must be ascribed to him. 

Concerning human evolution, the Church has a more definite teaching. It allows for the possibility that man’s body developed from previous biological forms, under God’s guidance, but it insists on the special creation of his soul. Pope Pius XII declared that "the teaching authority of the Church does not forbid that, in conformity with the present state of human sciences and sacred theology, research and discussions . . . take place with regard to the doctrine of evolution, in as far as it inquires into the origin of the human body as coming from pre-existent and living matter—[but] the Catholic faith obliges us to hold that souls are immediately created by God" (Pius XII, Humani Generis 36). So whether the human body was specially created or developed, we are required to hold as a matter of Catholic faith that the human soul is specially created; it did not evolve, and it is not inherited from our parents, as our bodies are. 

While the Church permits belief in either special creation or developmental creation on certain questions, it in no circumstances permits belief in atheistic evolution. 

http://www.catholic.com/tracts/adam-eve-and-evolution

HUMAN EVOLUTION!!!

MAMMALS

Say hello to your greatest grandparent. Cute, furry, long-tailed and with a penchant for insects – it sounds like something we would keep as a pet rather than be related to. But it seems that such a creature was the last shared ancestor of placental mammals – a group including all living mammals apart from marsupials and those that lay eggs. An exhaustive analysis, combining genomic information and fossil evidence, suggests that our ancestor lived soon after the asteroid impact that wiped out the dinosaurs 66 million years ago. Its descendants rapidly spread around the globe and evolved into all the major placental groups seen today, from bats to whales and from mice to men.

Molecular biologists and palaeontologists have long argued over the origin of placental mammals. For a long time, the accepted theory, based on fossil evidence, was that mammals had diversified after the dinosaurs were wiped out, exploding into myriad different species once the world was no longer dominated by these giants. However, recent genetic analyses have suggested that our earliest ancestor would have walked with the dinosaurs – living about 100 million years ago, and diversifying into more than 20 different lineages in the succeeding 35 million years. But palaeontologists have found no fossils from any modern placental group that date from before the impact, suggesting that the ancestor of living mammals evolved after the dinosaurs were gone. Family get-together In an attempt to resolve the conflict, Maureen O'Leary of Stony Brook University in New York state and colleagues built a family tree combining genetic information with data on more than 4500 anatomical traits – the most ever used in this way – from 46 living species and 40 fossil species.
None of the fossils dating from before the impact could be classified as modern placental mammals. The oldest fossil they identified as being a modern placental lived 200,000 to 400,000 years after the impact. Their analysis showed that rapid evolution followed, producing the first members of the major placental lineages, such as primates and rodents, about 2 to 3 million years later. The team's genetic analysis suggests that the last common ancestor was a small insectivore weighing between 6 and 245 grams that climbed trees and had a long furry tail (see image above). "We have no real idea" where it originated, or how its descendants spread around the world, O'Leary says. And although the reconstruction looks like a rodent, "its teeth were completely different". Boom or bust Placental mammals weren't the only mammals to diversify after the impact. Marsupials experienced a similar but smaller burst of evolution following the asteroid hit, with a single lineage leading to all living species, O'Leary says. As did the multituberculates – a group of rodent-like mammals that died without descendants 35 million years ago. Palaeontologist Donald Prothero at the Natural History Museum of Los Angeles County, is delighted with the results. "This is more in line with what the fossil record has told us for a long time," he says.

Lamarck's Scientific Thought

Beginning in 1801, Lamarck began to publish details of his evolutionary theories. Where men like Buffon had hinted at the possibility of evolutionary change, Lamarck declared it forthrightly. In 1801 he wrote: . . . time and favorable conditions are the two principal means which nature has employed in giving existence to all her productions. We know that for her time has no limit, and that consequently she always has it at her disposal. What was the mechanism for evolution? "Lamarckism" or "Lamarckianism" is now often used in a rather derogatory sense to refer to the theory that acquired traits can be inherited. What Lamarck actually believed was more complex: organisms are not passively altered by their environment, as his colleague Geoffroy Saint-Hilaire thought. Instead, a change in the environment causes changes in the needs of organisms living in that environment, which in turn causes changes in their behavior. Altered behavior leads to greater or lesser use of a given structure or organ; use would cause the structure to increase in size over several generations, whereas disuse would cause it to shrink or even disappear. This rule -- that use or disuse causes structures to enlarge or shrink -- Lamarck called the "First Law" in his book Philosophie zoologique. Lamarck's "Second Law" stated that all such changes were heritable.

The result of these laws was the continuous, gradual change of all organisms, as they became adapted to their environments; the physiological needs of organisms, created by their interactions with the environment, drive Lamarckian evolution. While the mechanism of Lamarckian evolution is quite different from that proposed by Darwin, the predicted result is the same: adaptive change in lineages, ultimately driven by environmental change, over long periods of time. It is interesting to note that Lamarck cited in support of his theory of evolution many of the same lines of evidence that Darwin was to use in the Origin of Species. Lamarck's Philosophie zoologique mentions the great variety of animal and plant forms produced under human cultivation (Lamarck even anticipated Darwin in mentioning fantail pigeons!); the presence of vestigial, non-functional structures in many animals; and the presence of embryonic structures that have no counterpart in the adult. Like Darwin and later evolutionary biologists, Lamarck argued that the Earth was immensely old. Lamarck even mentions the possibility of natural selection in his writings, although he never seems to have attached much importance to this idea. It is even more interesting to note that, although Darwin tried to refute the Lamarckian mechanism of inheritance, he later admitted that the heritable effects of use and disuse might be important in evolution. In the Origin of Species he wrote that the vestigial eyes of moles and of cave-dwelling animals are "probably due to gradual reduction from disuse, but aided perhaps by natural selection." Lamarckian inheritance, at least in the sense Lamarck intended, is in conflict with the findings of genetics and has now been largely abandoned -- but until the rediscovery of Mendel's laws at the beginning of the twentieth century, no one understood the mechanisms of heredity, and Lamarckian inheritance was a perfectly reasonable hypothesis. Several other scientists of the day, including Erasmus Darwin, subscribed to the theory of use and disuse -- in fact, Erasmus Darwin's evolutionary theory is so close to Lamarck's in many respects that it is surprising that, as far as is known now, the two men were unaware of each other's work. In several other respects, the theory of Lamarck differs from modern evolutionary theory. Lamarck viewed evolution as a process of increasing complexity and "perfection," not driven by chance; as he wrote in Philosophie zoologique.



Bibliography:http://www.ucmp.berkeley.edu/history/lamarck.html

Here is a link to a recent study related to evolution involving genetics. Really interesting!! http://www.secondspring.co.uk/articles/Evolution.pdf