Evidence for Evolution- Transitional Fossils Quiz

Answer: A fossil intermediate between two other fossils

Transitional fossils show the pathway of evolution from one type of animal to another. For example, Archaeopteryx was a fossil that showed characteristics of both its reptilian forebears and its avian descendants.

Answer: They show the intermediate steps in the evolution of a species

Transitional fossils document the evolution of species. For example, most people are familiar with the evolution of horses from small, multi-toed animals to large, hoofed animals. The many species in between Eohippus (now known as Hyracotherium,) the dawn horse, and Equus, the horse of today, are transitional fossils.

Answer: Evolution is rarely a straight-line process; it's a bush rather than an arrow

For example, the horse family tree has many branches (see http://www.talkorigins.org/faqs/horses/horse_evol.html for a great discussion of this.) Therefore, some of the branches were indeed not direct ancestors of the modern horse. But all of the branches were part of the same family tree, and a path (including all of the transitional fossils) can be traced from the "root" of the tree to the horse of today.

Answer: False

As we've mentioned, evolution is a bush, not an arrow. No scientist claims that man evolved from modern-day monkeys. Instead, both man and monkey share a common prosimian ancestor- we are different branches that share a common lineage. For a nice picture of the primate family tree, check out http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookHumEvol.html

Answer: Whales

Pakicetus ("whale from Pakistan") was discovered in 1979. Ambulocetus ("walking whale") was discovered in 1995.

Pakicetids did not look like whales at all. They had four legs, a long tail and snout, and were about the size of a large dog. What they had in common with the whales of today was the structure of the inner ear, which was adapted for hearing underwater. The whales are the only mammals that have developed this specialization. Their descendants, the ambulocetids, had more adaptations to aquatic life and resembled a mammalian crocodile. They retained the special inner ear.

As whales continued to evolve, subsequent species became more and more perfectly adapted to aquatic life.

Answer: The shape of the eye orbit in modern horses is unique and not found in any of the animals said to be ancestral to the horse

Hyracotherium was not a hyrax (a member of an Old World family of small mammals resembling rodents, but probably related to the elephants); no modern paleontologist has even suggested that it is. Its skull, including the tooth formula (one of the most important ways of determining what family a mammal is in) is completely different from a hyrax.
The idea that fossils of Hyracotherium and later horses are found together in the strata appears to be a misreading of a book published in the 1930's, according to an extensive investigation by paleontologist Kathleen Hunt. Even if it were to occur, it is not impossible to have occurred naturally. Remember, as we've stated before, evolution is a bush, not an arrow. It's entirely possible for one branch of the bush to split off and diversify, while the root of the branch still survives.
Even modern horses have varying numbers of pairs of ribs; Arabian horses, for example, usually have one less pair than most other horse breeds.
Even a small amount of research into truly scientific sources will discredit the creationist claims, yet the same claims are made over and over (usually copied word for word from each other!) When evaluating such claims, always look for evidence- what papers or books do they cite to back their claim? Are they creationist sources or true scientific journals?

Answer: Fossil-bearing strata were often destroyed in volcanic eruptions

What is amazing is that we have found so *many* clear and beautiful examples of transitional fossils, not so few!

Fossilization is a rare process that requires exact conditions to occur. Let's discuss animal fossilization as an example. In order to fossilize, the animal must die in an area where it will be quickly buried in large amounts of mud. Note how rarely that must happen! It must also not be eaten before the mud covers it. Then, the mud must be subjected to just the right amount of pressure to become sedimentary rock.

Many animals do not fossilize well. Only hard structures, like bones, can fossilize, thus a jellyfish fossil, for example, would not be easy to find.

The vast majority of the world has not been explored for fossil-bearing strata. Most major fossil discoveries of today are made during massive excavations, such as road-building.

Answer: That legs evolved in fish long before amphibians emerged on land

The limbs of amphibians first evolved in fish that crawled along the sea floor.

The first fish on the path to amphibians, the paleoniscoids, resembled today's coelacanth, with thick fins and lungs.

The next fish, Osteolepis, had leg-like, bendable fins, and an amphibian-like skull.

The next step, the rhipidistian lobe-finned fish, had fins that resembled legs, with joints, and an even more amphibian-like skull.

The next fish, the panderichthyids , looked very amphibian-like, with legs with feet and a straight tail.

Next we have fish such as Ichthyostega, , which most people would think to be amphibians. They had legs, feet, tails and skulls that were very amphibian-like.

The next group, the labyrinthodonts, are recognized as the first amphibians. But they still had vestiges of their fish ancestry, such as some gill-like structures and a skull hinge that was found in fish. Some even had internal gills. Their feet were build like modified fish flippers with the rays serving as toes- some early amphibians had seven or eight toes per foot!

Answer: Transition from the three-chambered reptilian heart to the four-chambered mammalian heart

Hearts do not fossilize well, thus we don't have a fossil record of this transition.

Reptiles have teeth that look the same, have no roots, and regrow continuously, while mammals have the familiar canines, incisors and molars, rooted teeth, and usually 2 sets of teeth in a lifetime. Transitional fossils document the evolution of all of these characteristics. For a detailed explanation, see http://www.talkorigins.org/faqs/faq-transitional/part1b.html

Answer: True

See http://www.talkorigins.org/faqs/faq-transitional/part2a.html for some extensive documentation. Some of the families with well-described fossil series include the:
Primates
Carnivores
Rodents
Lagomorphs (rabbits and hares)
Artiodactyls (cloven-hoofed animals like antelope and deer)
Cetaceans
Perissodactyls (odd-hoofed animals like horses and rhinos)
Sirenians (manatees and dugongs)

I hope you enjoyed and learned something from this quiz. If you are a creationist, I urge you, before writing me, to read all of the sources mentioned above. I would then love to discuss them with you.