Evidence for Evolution Stations Activity

Transcription

1 Evidence for Evolution Stations Activity Station 1 The Fossil Record Part 1 The Reading: read the article provided and answer the questions below 1. Who was Marie Curie? What did she discover? How did this help Darwin s argument for evolution? 2. In 1999, what fossil did paleontologists discover? 3. Evolution takes a long time but what about these examples? a. Viruses b. Reptiles c. Fish d. Horses 4. Which came first? (Circle the Answer) a. Vertebrates or Invertebrates b. Fish of Amphibians c. Mammals or Reptiles d. Bacteria or Everything Else 5. What is the significance of Chinese scientists unearthing fossils of the feathered dinosaur Sinornithosaurus millenji?

2 Part 2 Examine the diagram provided and answer the questions below. Assuming there has been no geological activity (e.g. tilting or folding), state in which rock layer (A-O) you would find: a) The youngest rocks at location 1: b) The youngest rocks at location 2: c) The oldest rocks at location 1: d) The oldest rocks at location 2: 1. Which layer at location 1 is about the same age as layer M at location 2? Explain your reasoning. 2. Which layers at location 1 are missing at location 2? 3. Which layers at location 2 are missing at location 1? 4. Using radiocarbon dating, the trilobite fossil was determined to be approximately 375 million years old. The volcanic rock layer (D) was dated at 270 million years old, while rock layer B was dated at 80 million years old. Give the approximate age range (ex. Greater than, less than, or between two dates) of the lock layers listed below: a. Layer A: b. Layer B: c. Layer C: d. Layer E: e. Layer L: f. Layer O:

3 Station #2: DNA Comparisons Background Information All living organisms use DNA and RNA to pass on hereditary information. The genes of many different organisms show important similarities at the molecular level. All living organisms have the same four kinds of DNA molecules (A,T, C, & G), these similarities in DNA show that there is common ancestry between all organisms on Earth. Examining DNA: Examine the DNA sequences provided at this station. Compare the sequences of the different species to the provided human sequence. Identify the number of substitutions (differences in the DNA bases) between each species and the human sequence and complete the table below. Humans vs. # of Substitutions % Difference (# substitutions/50) x 100 Mouse Roundworm Chimpanzee Fruit Fly E. coli % Similarity (100 - % difference) 1. What does this tell you about how related different organisms are? 2. Which of the above listed organisms are most related to humans? How do you know? 3. Which of the above listed organisms are least related to humans? How do you know? Using the chart on the next page: Compare each species amino acid sequence with humans. Circle the differences in amino acids that each species has compared with humans. Then answer the questions below. Species Human Common Gibbon Rhesus Monkey Chimp Gorilla Squirrel Monkey Ring-Tailed Lemur Horse Human Predict the order of closeness in which organisms are related to humans: Most related Least related 7.

4 Species I Human Arginine Cysteine Species 2 Common Gibbon Arginine Cysteine Species 3 Rhesus Monkey Cysteine Species 4 Chimp Arginine Cysteine Species 5 Gorilla Cysteine Species 6 Squirrel Monkey Arginine Cysteine Species 7 Ring-tail lemur Luecine Species 8 Horse Arginine Arginine

5 Station #3: Comparative Embryology Background Information The early stages, or embryos, of many animals with backbones are very similar. This does not mean that a human embryo is ever identical to a fish or a bird embryo. However, many embryos are very similar, especially during the early stages of development. From looking at the embryos it is clear that the same groups of embryonic cells develop in the same order and in similar patterns to produce the tissues and organs of all vertebrates. These common cells and tissues, growing in similar ways, produce the homologous structures found in very different living things. Analyzing the Evidence: Analyze the diagram and answer the questions below. 1. Examine Diagram 4a. Briefly describe how comparative embryology has contributed to the theory of evolution. In other words, look at the pictures of the different animal embryos, how are they similar and what must this tell us about evolution?

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7 1. Look again at the six embryos in their earliest stages. Describe the patterns you see. What physical similartieis exist between each of the embryos? 2. Does this suggest an evolutionary relationship? Explain how these embryos cab be used as evidence of a common ancestor between each of these six organisms. 3. Fruit fly embryos and frog embryos differ from each other more than frog embryos and human embryos do. What does this tell us about how each species is related? 4. The presence of gill slits in the early stages of an embryos development of an embryo indicates its future as a fish.true or FALSE?

8 Station #4: Anatomical Comparisons (Homologous Structures Background Information: There are many similarities among the body parts of animals with backbones. The limbs of reptiles, birds, and mammals vary in form and function but they are all constructed from the same basic bones. In addition the limbs of these animals all develop from the same clumps of cells in the embryos. Examining Structures: Examine diagram 4b containing images of homologous structures (similar structures) in the limbs of various species. 1. Describe the function of each set of bones shown in the picture. Animal Function of Limb Bird s Wing Mole s Forelimb Bat s Wing Dog s Front Leg Seal s Flipper Human Arm 1. Are the bones arranged in a similar way in each animal? Describe your answer. 2. What does this say about the ancestors of these six species?

9 Color In the Homologous Structures 3. How does the existence of homologous structures support the theory of evolution?

10 Station #5: Vestigial Organs Background Information: The organs of many animals are so reduced in size that they are just vestiges, or traces, of homologous (similar) organs in other organisms. These vestigial organs can resemble miniature legs, tails, or other organs. One good example is the vestigial legs found on many species of snake. Examining Vestigial Organs: Please read the paper on the vestigial organs of the Mole-Rat and Ostrich. Then write your hypotheses below for what the organs may have once been used for. 1. Mole-Rat Hypothesis 2. Ostrich Hypothesis Other Questions: 1. How are vestigial organs evidence for evolution? Explain your answer. 2. List and explain an organ found in modern animals that you think might be a vestigial organ.

11 Station 6 Fossils and Evolution 1. Give two similarities between each of the skulls that might lead to the conclusion that these are all related species? 2. What is the biggest change in skull anatomy from the dawn horse to the modern horse? 3. What is the biggest change in leg anatomy that occurred from the dawn horse to the modern horse?

12 Read the article then answer the questions Evolution of Whales Reading During the 1990s our understanding of whale evolution made a quantum jump. In 1997, Gingerich and Uhen noted that whales (cetaceans) "... have a fossil record that provides remarkably complete evidence of one of life's great evolutionary adaptive radiations: transformation of a land mammal ancestor into a diversity of descendant sea creatures." The trail of whale evolution begins in Paleocene time, about 60 mya, with a group of even-toed, hoofed, trotting, scavenging carnivorous mammals called mesonychians. The first whales (pakicetids) are known from lower Eocene rocks, that formed about 51 mya; the pakicetids are so similar to mesonychians that some were misidentified as belonging to that group. However, the teeth of pakicetids are more like those of whales from middle Eocene rocks, about 45 mya, than they are like the teeth of mesonychians. Pakicetids are found in nonmarine rocks and it is not clear how aquatic they were. In 1994, Ambulocetus natans, whose name means "walking whale that swims," was described from middle Eocene rocks of Pakistan. This species provides fossil evidence of the origin of aquatic locomotion in whales. Ambulocetus preserves large forelimbs and hind limbs with large hands and feet, and the toes have hooves as in mesonychians. Ambulocetus is regarded as having webbing between the toes and it could walk on land as well as swim; thus, it lived both in and out of the water. From late Eocene time onward, evolution in whales shows reduction of the hind-limbs, modification of the forelimbs and hands into flippers for steering, development of a massive tail, etc.; all of these changes are modifications for the powerful swimming of modern whales. The fossil Rodhocetus from the upper Eocene rocks, about 38 mya, of Pakistan already shows some of these modifications.