Evidence of Evolution



Name:_____________________________________________Period:______Date:____________

Evidence of Evolution Worksheet

Part I. ANALOGOUS STRUCTURES

Some apparently unrelated animals have organs with similar functions, yet are very different in structure and form. These structures are called analogous structures.

1. Examine the butterfly wing and the bird wing shown in Figure 2.

a. What function do these structures share?

b. How do the structures differ?

Part II. VESTIGIAL STRUCTURES

Gradual changes have occurred through time that have in some cases reduced or removed the function of some body structures and organs. The penguin’s wings and the leg bones of snakes are examples of this phenomenon.

1. The cave fish and minnow show in Figure 3 are related, but the cave fish

is blind.

a. Explain why eyesight is not an important adaptation to life in a cave.

What are organs or structures that have lost their function in the organism and become reduced in size called? __________________________________

Part III. HOMOLOGOUS STRUCTURES

These structures are formed in similar ways during embryonic development and share like arrangements; however, they have somewhat different forms and functions. They are called homologous structures.

1. a. Color each part of the human arm a different color. (All bones of the wrist should be a

single color, the bone groups of the hand should be a different single color.) Then color

the corresponding bone in each of the other animals the same color as the human bone.

b. Next to each bone, write the function. In other words, what does each animal use the

bones for?

[pic]

Part IV - Read the list of human vestigial structures shown in Table 2.

c. Given the probable function for each structure, why do you think it is now considered

vestigial. Record your answers in the table.

Table 2.

|Structure |Probable Function |Why Vestigial? |

|appendix |Thought to have had bacteria that helped to | |

| |digest cellulose. | |

|coccyx (tail bone) | | |

| |Helps for balance in animals that spend a | |

| |majority of their time on 4 legs. | |

|muscles that move ears | | |

| |Help an organism hear in all directions. | |

|wisdom teeth | | |

| |Help to break down really tough food such as | |

| |raw vegetables. | |

Part V - BIOCHEMICAL COMPARISIONS

Red blood cells make large amounts of an iron-containing protein called hemoglobin. The purpose of hemoglobin (a red pigment) is to transport oxygen throughout your body to your cells.

▪ Examine the amino acid sequences below which compare corresponding portions of hemoglobin molecules in humans and five other vertebrate animals.

Use the information found in Table A (below) to complete the following steps:

Step 1: Put an X in the blank under each numbered column (() in which all of the organisms have the same amino acid.

1. How many columns were the amino acids the same for all of the organisms? _________________________

Step 2: Now look at the columns in which there are differences (you didn’t put an X). Circle the amino acids in each column that are different from the human amino acid in the same column.

Table A: Comparing hemoglobin of a human to other organisms.

| Amino Acid # 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 |# of |

| |Differences |

|Humans THR LEU SER GLU LEU HIS CYS ASP LYS LEU HIS VAL ASP PRO GLU | |

|Chimpanzee THR LEU SER GLU LEU HIS CYS ASP LYS LEU HIS VAL ASP PRO GLU | |

|Gorilla THR LEU SER GLU LEU HIS CYS ASP LYS LEU HIS VAL ASP PRO GLU | |

|Rhesus monkey GLN LEU SER GLU LEU HIS CYS ASP LYS LEU HIS VAL ASP PRO GLU | |

|Horse ALA LEU SER GLU LEU HIS CYS ASP LYS LEU HIS VAL ASP PRO GLU | |

|Kangaroo LYS LEU SER GLU LEU HIS CYS ASP LYS LEU HIS VAL ASP PRO GLU | |

____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____

Table A: (continued)

| 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 |# of |

| |Differences |

|Humans ASN PHE ARG LEU LEU GLY ASN VAL LEU VAL CYS VAL LEU ALA HIS | |

|Chimpanzee ASN PHE ARG LEU LEU GLY ASN VAL LEU VAL CYS VAL LEU ALA HIS | |

|Gorilla ASN PHE LYS LEU LEU GLY ASN VAL LEU VAL CYS VAL LEU ALA HIS | |

|Rhesus monkey ASN PHE LYS LEU LEU GLY ASN VAL LEU VAL CYS VAL LEU ALA HIS | |

|Horse ASN PHE ARG LEU LEU GLY ASN VAL LEU ALA LEU VAL VAL ALA ARG | |

|Kangaroo ASN PHE LYS LEU LEU GLY ASN ILE ILE VAL ILE CYS LEU ALA GLU | |

____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____

Step 3: In the FAR RIGHT column of the table, identify how many amino acids were circled for each animal.

2. Identify how many total differences of amino acids each of following organisms had when compared to the human amino acid (make sure you include the numbers from both tables above).

a. Chimpanzee _____________

b. Gorilla _________________

c. Rhesus monkey ______________

d. Horse __________________

e. Kangaroo___________________

3. Based on the information from table A, which organism is most closely related to humans? ___________

4. Based on the information from table A, which organism is least closely related to humans? ___________

Part VI. Fossil Evidence

Use the information found below to answer the following questions.

Relative Dating:

There is an enormous amount of evidence that supports the theory of evolution. Much of this evidence is found in the rocks of the Earth itself.

o The approximate age (relative age) of a fossil can be determined through relative dating. This technique is based on the fact that new layers of rock are deposited on top of older layers of rock.

o Relative Age is based on the Law of Superposition (proposed by Nicholas Steno in the 1600s).

1. In which layer would you find the oldest fossil? _______________

2. In which layer would you find the youngest fossil? ____________

If some of the fossils found in layer C are found to be about 50 million years old, are the fossils in layer B less than or more than 50 million years old ? Explain your answer.

3. Are the fossils in layer D the oldest or youngest fossils? Explain your answer.

Absolute Dating

Radioactive isotopes lose their excess weight in the form of subatomic particle emissions (in other words, by losing neutrons or protons). Below is a diagram showing a block of radium losing its radioactivity over a period of time. The half-life for radium is 1,620 years (the amount of time it takes for half of the radioactive isotope to decay).

1. On the line under each BOX, write the fraction of the radioactive radium that is left from the original sample . I began filling these in for you. Write in the last 2.

[pic]

____________ ____________ ___________ _____________ ___________

2. How many years has it taken for the radium to decay to the amount that is shown in the last box (add up all of the years between boxes)? ____________

The fossils pictured below were removed from various strata of an excavated site. Once recovered, the ratio of C14 to C12 was measured for each fossil. The half-life of C14 is 5,720 years.

o While living, organisms are constantly taking in C14 at a uniform rate. Once they die, they no longer take in C14. Between the death of an organism and the time of its fossil dating, C14 decays into C12. In other words, in 5,720 years, half of the Carbon 14 that was initially in the fossil will have decayed into Carbon 12.

[pic] [pic] [pic] [pic]

FOSSIL A FOSSIL B FOSSIL C FOSSIL D

Find the age of each fossil shown below from the fraction of C14 that is left. Follow the above example!!! In order to answer these questions you will need to figure out the number of half-lives that have passed.

1. Fossil A, 1/2 of C14 remains. What is the age of this fossil? __________________________

2. Fossil B, 1/4 of C14 remains. What is the age of this fossil? ___________________________

3. Fossil C, 1/8 of C14 remains. What is the age of this fossil? __________________________

4. Fossil D, 1/16 of C14 remains. What is the age of this fossil? ____________________________

-----------------------

[pic]

[pic]

A

B

C

D

1620

1620

1620

1620

D

C

B

A

¼

½

1

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download