Science in Motion
Ursinus College
Time needed to complete lab: two class periods
Target Grade Level: 10-12 all levels (introduction to the topic of evolution)
Objectives

Analyze information that could be used to support the theory of evolution

Understand the scientific use of the word theory

Understand the concept that similarities in DNA, embryology, and anatomy are used to determine evolutionary relationships

To realize the special importance of DNA in determining evolutionary relationships

Differentiate between homologous and analogous structures
Major Concepts (background information)
One important thing that teachers should emphasize in this lab is the difference between the word “theory” in common speech and the word “theory” when used in science. In common speech, theory is a little more than a guess but in science, the work theory means an idea that has been supported by data. Over hundreds of years, humans have collected data on the variation and complexity of life and evolution is an explanation of how and why life has changed.
In 1831 Charles Darwin began a five-year journey as ship's naturalist on the H.M.S. The
Beagle. During this time he visited South America, Australia, South Africa, and islands of the
Pacific and South Atlantic. He later published his travels in The Voyage of the Beagle where he introduced many themes that later became crucial to the arguments presented the more-familiar
The Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life (published in 1859 and more commonly known as " The Origin of Species ").
Majors in the sciences and those interested in philosophy should read this monograph. You won't find it easy reading because the language is often archaic and the arguments are sometimes difficult to follow, but it represents one of the most important contributions made to Western culture.
Although Darwin is often referred to as "the father of evolution", he was not the first to introduce the idea of changing species. Maupertuis and Diderot in the mid 18th century, for example, wrote of evolution and the ideas of changing life are part of many religions. Darwin's contribution was to provide a mechanism through which evolution could function. Briefly, the
Darwinian argument is as follows:

Variation exists within a species.
Although we may consider all houseflies as being more-or-less alike, on closer examination you find that they are nearly as recognizable as one person is from another.

Some of this variation has a genetic basis.
Evolution can act only on traits that are
 passed genetically from one generation to the next. Just as animal or plant breeders have no interest in non-genetic traits, evolution can not work on differences due to trauma, parasitism, and other environmental variation.
The reproductive potential of organisms is vast.
Darwin calculated that a single pair of

elephants could have 19 million descendants within 750 years if each animal lived to be
100 and each pair had six calves. Calculations for other organisms produce similar increases in population size. Elephants are not the most common beasts, the oceans are not overflowing with fish and we aren't nose-deep in ragweed (although it sometimes seems that way). Therefore something must happen to all these extra offspring and, unless species other than man practice birth control, most of the young must die before they reproduce.

Because individuals differ from one another, some should be more capable than others in eluding predators, coping with environmental extremes, or in competing with members of their own or other species.
Those that are more capable should leave more offspring to the succeeding generation. Since some aspects of coping must be tied to genetic attributes, the favorable genes are passed on to the next generation. The genetic makeup of the population changes and evolution is said to occur. This varying reproductive success of individuals based on their different genetic constitutions is natural selection .
Often the concept of natural selection is simplified to "survival of the fittest". Fitness in evolutionary terms has an exact meaning related to the number of surviving offspring produced by an individual in comparison to less well-endowed individuals. Evolutionary fitness is therefore more than just the ability to run quickly or fight off competitors.
Preparation:
This lab is best done as learning stations with the students moving from learning station to learning station. It is recommended that students move as lab groups and that each group is assigned one organism to do the serology work on. The results of the serology section should be put on the board so the results can be shared by the all the groups.
Answers to questions: Other fossils can be used. The information below is for the
fossils that come with this particular lab.
Part I-Fossil Evidence
Fossil Identification Method of Formation
1.
2.
Petrification
Mold
Present Species Similar to
Fossil
Some mollusk-ex. cuddlefish
Fern or any fern species
4.
5.
Petrification
Petrification
Any bony fish species
Any tree
An arthropod-ex. horseshoe
crab

Key to Numbered Fossils
1. Ammonite
These are an extinct group of marine animals in the class Cephalopoda, phylum
Mullusca. Even though they look a lot like a chambered Nautilus, they are more closely related to the octopus, squid, and cuddlefish. They became extince during the Cretaceous period about 65 m.y.a. and had first appeared during the Devonian Period about 400 m.y.a. They were named after the Egyptian god Ammon by Plinius the Elder because the god was typically depicted wearing ram’s horns. They lived in open seas and were thought to be good swimmers. They preyed on fish, crustaceans and other small animals.
This fossil was found in England.
2. Fossil Fern
These fern fossils are a good example of mold fossils. The fern material completely decomposed and an imprint of the fern frond is left behind. This particular fossil comes from Pennsylvania which is famous for its fossil ferns. Although many types of ferns exist today, the fern that formed this fossil is extinct.
There are two sets of the evolution lab. Fossil 3 will differ depending on the set.
3. Rhacolepsis (fish)
This extinct bony fish lived 100 m.y.a. during the Cretaceous Period. It was a predator and was found in Brazil.
3. Megatooth shark tooth
Today, the only remains of the largest meat-eating fish to ever live, are a few vertebrae and teeth. Carcharodon megalodon , the giant "Megatooth" shark, ruled all the warmwater seas during the Neogene Period [Miocene (5-24 million years ago (mya)) and
Pliocene (1.67-5 mya)].. The teeth of the giant "Megatooth" shark are prized by amateur fossil collectors. Scientists believe that the living Great White Shark which is in the same genus, can reach up to 35 to 40 feet in length. So it was not unbelievable to estimate
"Megatooth" reaching 100 to 120 feet in length when it had teeth three times the size of a
Great White Shark.
4. Petrified Wood
This fossil is from is from Oregon. It consists of fossil wood where all the organic material has been replaced by minerals, while retaining the original structure of the wood.
The petrifaction process occurred underground, when the wood was buried under sediment. Mineral-rich water flowing through the sediment deposited minerals in the plant’s cells and as the plant’s lignin and cellulose decayed away, stone took its place.
Petrified wood can preserve all the original structure of the wood down to the microscopic level. The tree rings in this polished sample are very visible.
5. Trilobite

These organisms were among the early arthropods. They have the classic hard shells, body segments and jointed legs that are characteristic of this phylum. There are 15,000 described species and new species are unearthed each year. This is the most diverse group of extinct organisms. They vary from under a millimeter to 70 cm in length. They filled a wide variety of niches in the environment from scavengers to predators. They existed 300 m.y.a. and lived in ancient seas. They became extinct before the time of the dinosaurs. Trilobite means “three lobes.” Looking from head to tail, this specimen has left and right lobes and a center lobe. This particular fossil is from Morrocco.
Part II – Comparative Anatomy
The purpose of this part of the lab is to have students become aware of the concept that organisms are modified to fit the environment and that in most cases the organisms have the same structures but their shape is different to perform a different task.
Part III- Embryology
Student answers will vary widely but the goal of this part of the lab is to see the great similiarity of organisms during the embryolic stages.
Part IV-Comparative Serology
Dilution 1 2 3 4 5
Chimp ++++ ++++ ++++ ++++ +++
6
+++
7
+++
8
++
Gorilla ++++ ++++ ++++ ++++ ++
Orang ++++ ++++ ++++ ++ +++
++
++
+
+
-
+
Swine + -
Part V – Molecular Biology
If you look at the differences in DNA sequences, chimps and gorillas have three differences from the human code for this segment and orangutans have five. Banding pattern wise, the chimp and the orangutan look most similar to the human. From this information, I would say that the chimp is the most closely related to humans.