Evolution

1. Evolution

2. Biological Diversity • Variety in living things

3. Evolution • Changes over time. • The process by which modern organisms have descended from ancient organisms.

4. The Problems • Hoaxes (Piltdown Man, • Fossil evidence was sporadic • Geology and Biology are both young sciences….only 300 years old.

5. The Piltdown Man • The "Piltdown Man" is a famous hoax consisting of fragments of a skull and jawbone collected in 1912 from a gravel pit at Piltdown, a village near Uckfield, East Sussex, in England. The fragments were thought by many experts of the day to be the fossilized remains of a hitherto unknown form of early human. The Latin name Eoanthropusdawsoni ("Dawson's dawn-man", after the collector Charles Dawson) was given to the specimen. • The significance of the specimen remained the subject of controversy until it was exposed in 1953 as a forgery, consisting of the lower jawbone of an orangutan combined with the skull of a fully developed, modern man. • The Piltdown hoax is perhaps the most famous paleontological hoax in history. It has been prominent for two reasons: the attention paid to the issue of human evolution, and the length of time (more than 40 years) that elapsed from its discovery to its full exposure as a forgery.

6. Hoax….Archaeoraptor liaoningensis • In October 1999 paleontologist Philip J. Currie of the Royal Tyrrell Museum of Paleontology in Drumheller, Alberta along with Stephen Czerkas of the Dinosaur Museum in Blanding, Utah, and Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing announced the discovery of Archaeoraptor at a National Geographic Society press conference in Washington, D.C. • The fossil was considered to be a missing link between birds and dinosaurs because it manifested the long bony tail of dromaeosaurid dinosaurs and the specialized shoulders and chest of birds.

7. Continued….. • Let it be noted that this fossil did not even make it to peer review. Science doing what science does and scientists doing what real scientists do have revealed this fossil (or rather fossils) for what it is. This is not an embarrassment for science but a reason for science to stand proud. This fossil was rejected during the most preliminary of studies - it did not even reach the first step of scientific acceptance, that of description. While laypeople may not understand, publication in National Geographic, which is a general interest magazine for the public and not a peer reviewed scientific journal, is not scientific recognition and acceptance.

8. Problems • (Williamson, 1981, p.214). "Scientists have dug up fossils of what they say are some of the earliest ancestors of modern sea turtles. The 110 million year old fossils of several turtles are the earliest remains of their kind found in Australia. Palaeontologists from the South Australian Museum and the University of Adelaide made the discovery, from the Early Cretaceous period, at a dig near Boulia in western Queensland. Research scientist Dr Ben Kear says the fossils suggest the Cheloniidae family of modern turtles had some of their earliest origins in Australia. "They look like they might be at the base of the modern sea turtle," he says. ... One of the Boulia fossils was "about as complete as you can get with fossils", Kear says, showing the turtle's blood vessels, nerve channels and muscles, and allowing detailed exploration of the brain cavity. He says the turtle closely resembled a modern sea turtle." (Skatssoon J., " Early turtle ancestor found," ABC, 21 February 2005) [Another example of stasis, i.e. no evolution. - for ~110 million years.]

9. Problems • "A spider relative called a harvestman trapped in amber could shed light on how arachnids were affected by the extinction that wiped out dinosaurs. The 100-million-year-old arachnid, which looks like it might have died last year, wandered though a dinosaur-dominated world. .... "This specimen came from the Mesozoic Era, so basically the same time as the dinosaurs and generally there are very few fossil arachnids from this period," said co-author Jason Dunlop. ... One of the reasons this specimen is causing excitement is that it might help tackle the question of how many arachnid groups managed to survive the great extinction of around 65m years ago. ... . The harvestman hit on a successful evolutionary "design" fairly early on and has changed rather little over the past few hundred million years. "We think they would have lived a similar life to modern harvestmen," said Dr Dunlop. "If you go back to a very, very ancient fossils and look at the internal organs, you see it actually has reproductive organs just the same as a living one; it has a breathing system the same as a living one. So, it looks like there hasn't been any major change in the body plan." ... [So yet another example of stasis (no evolution for ~300 million years! How many generations? How many environmental changes? And this "100-million-year-old arachnid, ... looks like it might have died last year"!] ("Arachnid's clue to dino wipeout," BBC. 18 May, 2005). [So yet another example of stasis, i.e. no evolution - for ~300 million years! How many generations? How many environmental changes? Yet no RM&NS? And this "100-million-year-old arachnid ... looks like it might have died last year"!] [top]

10. Support The gradual change of fins to feet.

11. Interesting Link for deep reading • http://plato.stanford.edu/entries/evolution/

12. Support for Gradual Change • The anatomy of the hand of a blue whale.

13. Support for Gradual Change

14. Evidence for Evolution and Controversy • Fossils offer evidence that life on the earth is measured in millions and billions of years, rather than thousands as believed by young-earth creationists. Fossils also reveal that there are ancient forms of organisms that no longer exist; in other words, that extinction is a fact. The geologic time scale shows the history of life on earth, as determined by the fossil record.

15. Continued….. • In addition, the fossil record supports the view that events of speciation are normally concentrated in geologically short periods of time, and that species tend to remain morphologically stable throughout most of their existence. Such a fossil record is consistent with the theory of punctuated equilibrium as presented by Stephen Jay Gould and Niles Eldredge. This is currently contrary to the theory of small changes over time according to the evolutionary hypothesis. This theory seems to be true for time scales within geologic strata.

16. The fossil record also offers evidence of the theory of descent with modification—that organisms descend from common ancestors. For example, Georges Cuvier documented that the lower (older) the rock strata, the more different the fossils were from living organisms. Indeed, fossils found in more recent geological strata tend to be very similar to, or indistinguishable from living species, but fossils in older geological strata tend to be markedly different. Fossils also reveal that organisms of increasing complexity have appeared on the earth over time. This is consistent with the view that each stage builds upon preceding stages. Fossil evidence that supports the view of species stability throughout their existence, and sudden appearances of new species, is not problematic for the theory of descent with modification, but only with Darwin's concept of gradualism.

17. Some fossils have been considered to be transitional fossils—having characteristics that appear to be between the (assumed) ancestral and descendant forms. For example, Archaeopteryx has been presented as a transitional fossil between reptiles and birds. In 2006, a fossil fish (Tiktaalik roseae) was found in northern Canada that appeared to bridge the gap between fish and tetrapods (four-legged vertebrates), looking like a cross between a fish and a crocodile. However, few transitional fossils have been reported, and many scientists are cautious about these findings. Among other problems, Archaeopteryx, which appears fully formed in the fossil record, is not preceded or followed by fossils showing a gradual transition between reptiles and birds and, according to some theories of bird evolution, appears to have lived after the common ancestor. In general, the gap between separate fossils is so large that it is difficult to be definitive on ancestral-descendant relationships.

18. One of the problems with fossil evidence for evolution is that there are few gradually sequenced intermediary forms. Fossil lineages from therapsid reptiles to mammals, between supposed land-living ancestors of the whales and their ocean-living descendants, and from an ancestral horse (Eohippus) to the modern horse (Equus) are reasonably well-represented. But, generally, discontinuities or gaps are found in phyletic series rather than a gradual change from ancestral forms to descendant forms. The incompleteness of the fossil record is one explanation given for this, as well as rapid speciation via punctuated equilibrium. • What fossil evidence does not support is the view of natural selection as the creative force of evolution (theory of natural selection). Rather, the fossil record is neutral with respect to the mechanism of evolutionary change.

19. Archaeopteryx is a Jurassic fossil bird that shares both bird and reptile features; it is widely accepted as the earliest and most primitive known bird. Fossils show the presence of wings and feathers, as in birds, but also teeth (which modern birds do not have), claws on the wings, and a long, lizard-like tail, with tail vertebrate, such as with reptiles (Mayr 2001). The description of the first intact specimen in 1861 (two years after Charles Darwin published The Origin of Species), set off a firestorm of debate about evolution and the role of transitional fossils that endures to this day.

20. Further support of evolution • Over the years, ten specimens of Archaeopteryx have been found, all in a limestone deposit near Solnhofen, Germany. The fine-grained limestone, which preserves detailed casts of features not often fossilized, is used by artists and printers for lithographic plates, thus the species name Archaeopteryx lithographica. These fossils are attributed to the Upper (or Late) Jurassic period, about 145 million years ago.

21. As a fossil that fills a large gap between reptiles and birds, Archaeopteryx has been referred to as a missing link (Mayr 2001). At one point, it was also widely considered a direct ancestor of modern birds, but many current paleontologists view it now as a side branch. There are divergent theories on whether birds arose from archosaurian reptiles in the late Triassic, more than 200 million years ago, or from theropod dinosaurs in the more recent Cretaceous, about 80-110 million years ago. The two camps, understandably, view differently where Archaeopteryx fits in the scheme between reptiles, or dinosaurs, and modern birds.

22. Since its timely discovery in 1860 and description the next year, shortly after Darwin predicted such transitional fossils in The Origin of Species, Archaeopteryx has been presented as evidence for Darwin's theory of descent with modification. As such it has gained a great deal of notoriety, not only in scientific discourse but also in textbooks and the public media. Nonetheless, despite the significance attributed to this species, Archaeopteryx does not significantly illuminate possible transitions between reptiles/dinosaurs and birds, since it appears in the fossil record fully formed, with a lack of any transitional forms between reptiles or dinosaurs and itself. The history surrounding Archaeopteryx does reveal, however, much about the process of science, with competing theories espoused by different camps, and at times a tendency to espouse seemingly definitive conclusions beyond that of the known facts.

23. It is unclear where Archaeopteryx fits in the evolution of birds. There are two major conjectures regarding the origin of birds. The thecodont theory holds that birds arose from archosaurian reptiles, perhaps in the late Triassic more than 200 million years ago. The dinosaurian theory holds that birds evolved from theropod dinosaurs at an earlier date. • Some consider Archaeopteryx to be a powerful piece of evidence that birds evolved from dinosaurs. The skeleton is similar to the dinosaurs of the families Dromaeosauridae and Troodontidae. However, Archaeopteryx also presents a complication in this matter. The most bird-like, bipedal dinosaurs, which are presented as the ancestors of birds, actually trace to the Cretaceous, about 70 to 100 million years ago, or well after Archaeopteryx, the earliest known bird, had disappeared. • Mayr (2001) feels that Archaeopteryx, which lived 145 million years ago in the Jurassic, has so many advanced avian characters that the original birds must have existed sometime earlier, perhaps in the Triassic, 200 million years ago. Yet, there have not been any bird-like dinosaurs known from the Jurassic, or earlier. This would offer support for the view that birds arose from archosaurian reptiles.

24. TimeScales • Deep Time • Geologic Time Scale

25. Darwin’s Theories • Individual organisms in nature differ from one another. Some of this variation is inherited. • Organisms in nature produce more offspring than can survive, and many of those that survive do not reproduce. • Because more organisms are produced than can survive, members of each species must compete for limited resources.

26. Darwin’s Theories contin…. • Because each organism is unique, each has different advantages and disadvantages in the struggle for existence. • Individuals best suited to their environment survive and reproduce most successfully. The characteristics that make them best suited to their environment are passed on to offspring. Individuals whose characteristics are not as well suited to their environment die or leave fewer offspring.

27. Darwin’s Theories Contin…. • Species change over time. Over long periods, natural selection causes changes in the characteristics of a species, such as in size and form. New species arise, and other species disappear. • Species alive today have descended with modifications from species that lived in the past.

28. Darwin’s Theories Contin… • All organisms on Earth are united into a single tree of life by common descent.

29. Voyage of the HMS Beagle

30. Hutton’s Theory of Geologic Change • In 1785, the geologist James Hutton published a detailed theory about the geologic forces that have shaped Earth. He proposed that layers of rock form very slowly. Also, some rocks are moved up by forces beneath Earth’s surface. Others are buried, and still others are pushed up from the sea floor to form mountain ranges. The resulting rocks, mountains, and valleys are then shaped by natural forces. These processes happen over millions of years.

31. Lyell’s Principles of Geology • Charles Lyell stressed that scientists must explain past events in terms of processes that they can actually observe. • Processes that shaped the earth millions of years ago are happening in the present.

32. Lamarck’s Theory of Evolution • In 1809, Lamarck published his theory of how organisms changed over time. • He proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits could then be passed on to their offspring. Over time, this process led to change in a species.

33. Lamarck’s Theories • Tendency toward Perfection - All organisms have an innate tendency toward complexity and perfection. Changing features help them to be more successful in their environment. • Use and disuse - • Acquired characteristics could be inherited.

34. Problems with Lamarck’s Theories • Lamarck did not know how traits were inherited. • Behavior has no effect on inheritable characteristics.

35. Population Growth • In 1798, Thomas Malthus observed that babies were being born faster than people were dying. • He reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone. • Forces that worked against growth were war, famine, and disease.