Name __________________________ Date ...



Name __________________________ Date __________________ Biology: Period ____

Lab: Exploring Evidence for Evolution

I. Fossil Evidence

Part A: Examine the fossils collected throughout Michigan and answer the questions that follow.

1. What type of organisms do they represent?

2. Do the fossilized remains look similar to organisms alive today? Explain.

3. How has this area changed since the time these fossilized organisms were living?

Part B: Watch the video depicting the endosymbiotic theory, and answer the questions that follow.

4. What does the similarity between the mitochondria and bacteria imply?

5. The endosymbiotic hypothesis suggests that organelles in our cells were once bacteria. What evidence in the video supports the endosymbiotic theory?

6. Explain how we inherit mitochondria from our mothers.

II. Evidence from Homologous Structures

Many animals share similar body structures that have the same internal structure and location, yet these structures serve different functions. A structure’s shape is often related to its function. A hand used for swimming (a fin) is shaped differently than one used for supporting an animal’s weight as it walks. Likewise, a hand used for flying (a wing) is shaped differently than one used to manipulate objects or tools.

In the following activity you will observe X-rays of several different animals’ “hands.”

Complete the chart below.

|X-ray # |Name of animal |# of “fingers” |Shape of flesh over bones |Function of the hand |

| | |Separate fingers? | | |

|#1 |Human | | | |

|#2 |Hyena | | | |

|#4 | Macaque | | | |

|#7 |Beluga | | | |

|#9 |Owl | | | |

1. Are the hands of these animals homologous? Explain.

2. What inferences can you draw about the ancestry of these animals?

III. Embryological Evidence

Obtain an envelope of pictures of different embryos. There are 3 pictures for each of the 6 organisms. Start by putting the 1st picture for each animal at the top of your work

space. Attempt to match the more developed picture with the beginning stages.

When you have finished, your teacher will initial your paper and verify your matches.

1. What did you notice about the first stages of all of the embryos?

2. What controls an organism’s development and growth of body structures?

3. If the development of an organism is controlled by its genes…what could you hypothesize about the DNA of these embryos?

IV. Evidence from Biochemical Comparisons

Another technique used to determine evolutionary relationships is to study the biochemical similarity of organisms. Biochemists study both the protein sequences and the DNA sequences to determine a quantitative estimate for the degree of relationship between different organisms. By comparing the sequence of amino acids for a protein biologists can infer the relationship. The more similar the sequence, the more closely related the two organisms are.

The table below shows a portion of the protein, hemoglobin. Hemoglobin is the oxygen carrying molecule in red blood cells. The 3 letters are abbreviations for different amino acids.

[pic]

1. How many differences exist between the following:

a. human and chimpanzee: ___________

b. human and gorilla: _______________

c. human and rhesus monkey: ______________

d. human and horse: ___________

e. human and kangaroo: ___________

2. On the basis of the data above, which organism appears to be most closely related to humans? ______________ Least related? _________________

3. If you assume that humans and gorillas had a common ancestor, what caused the amino acid difference?

4. If the amino acid sequences in a protein of two organisms are similar, why will their DNA also be similar?

V. Other

Read the article “Chew On This: Teeth Found In Mutant Line Of Chickens”.

1. According to this article birds descended from reptiles. What is their reasoning?

2. Modern chickens do not have teeth, but they still have the gene to make teeth. Explain what happened to this gene.

3. If you found small teeth in a turkey’s mouth, what term would be used to describe them?

VI. Evidence from Chromosomes

Obtain of the diagram of the monkey’s chromosomes. Mutate the monkey’s chromosome to match the chromosome below. Glue your mutated chromosome down so that it aligns with the one below.

[pic]

1. The chromosome on the previous page is the human chromosome #1. What does this illustrate about the relationship between a monkey and a human?

VII. Biogeographical Evidence

In this field of science, scientists determine how the differences in environments have affected the evolutionary history of different species of common origin. Answer the following questions after reviewing the pertinent facts about the ostrich and emu.

1. Why do scientists think these two birds have a common ancestor?

2. How do these two organisms illustrate biogeographical evidence for evolution?

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