Biology

6. List the 3 types of evidence for evolution.

. Fossil record . Geographic Distribution . Homologous Structures

14. What is a cladogram? What can a cladogram tell us?

A cladogram is a diagram that represents the evolutionary relationships between different species. It shows how organisms descended and the common ancestors of these organisms.

15. What is an index fossil?

An index fossil is a fossil of an easily identifiable organism that existed for a short period of time in a wide geographic range. Index fossils are used the help determine the age of fossils by indicating which time period they came from.

4. What are analogous structures and list an example of analogous structures in two different species.

Analogous structures are structures that show a similarity in structure and function between 2 unrelated species. An example is the wings of birds and insects. Both structures help the organism fly, but they are not developed similarly not do they consist of the same tissues.

20. What is comparative embryology and what does this tell us about evolution?

Comparative embryology is comparing the embryos of different species. The similarity in the embryos indicates that the organisms may have had a common ancestor.

24. How did mitochondria and chloroplast originate in the first eukaryotic cells?

Endosymbiotic theory states that the mitochondria and chloroplast originally were cells that existed on their own. Over time they migrated into other cells and began to perform different functions in cells. They helped to form the first primitive animal cell.

21. List some examples of homologous structures and what does this tell us about evolution?

Examples of homologous structures are the bones of a cat's leg, bird's wing, whale's flipper and a human arm. They are homologous because they formed from the same embryonic tissue but developed into different mature structures.

25. How would a scientist use each of the following to prove that two species are closely related?

Fossils,DNA or molecular evidence,Homologous structures,embryology

5. Where would a scientist likely find a fossil?

In sedimentary rock

19. What does the fact that all organisms have DNA tell us about a common ancestor?

It indicates that that all organisms have a common ancestor.

17. If 2 organisms do not have many of the same amino acid sequences, they would be (more, less) related to each other.

Less

8. Where are the oldest fossils found in sedimentary rock? Where are the youngest fossils found?

Oldest fossils will be found in deep layers of sedimentary rock Youngest fossils will be found in more shallow layers of sedimentary rock

11. Why might a scientist find fossils in different layers of rock that are similar but not exact copies of each other?

One organism may have evolved from another organism so they would show similar, but not the same fossil remains.

9. What causes sedimentary rock?

Sediments in rivers and streams settle on a dead organism, covering it up and protecting it from the environment. Sediments are caused by the erosion of rock by water and wind.

22. Describe 2 methods that a scientist could determine if two species of birds are related to each other?

The best method is to examine the DNA of the two bird species for similarity. Another method is to examine homologous structures of the organisms for similarity. 

2. What is the best way to determine if two species are closely related?

The best way is to compare the DNA of the two species. The more nitrogenous bases and amino acids two species have in common, the more closely related they are.

12. Why do some whales have a pelvic bone although they have no legs?

The pelvic bone is a vestigial structure that indicates that whales may have had legs at one time, but were selected against so they were reduced in size.

10. Why are most fossils found in areas that once were covered with water?

They are found in water areas because this is where most sediment is formed and deposited on a dead organism.

18. What can the amino acid sequences between two organisms tell us?

They can show how closely related 2 organisms are to each other.

Would two organisms on a cladogram that are far apart have more or less amino acids in common?

They would have less amino acids in common.

3. If you observed the bones in a dolphin's flippers and the bones in a human hand, you would see that they are not the same. However they both come from the same embryonic tissue. What is this an example of?

This is an example of homologous structures.

How do vestigial structures add to the evidence of evolution?

Vestigial Structures show that organisms contain structures that are no longer used that may have once been used by an organism. It shows that nature selected against the structure and it is no reduced in size. An example is the Human Appendix that may have once been used in digestion.

1. What is a vestigial structure? List an example of a vestigial structure.

Vestigial structures are structures in animals that are reduced in size to where they are just traces of homologous structures in other species. Examples would include the human tail bone, certain bones in whales and the human appendix.

16. If 2 organisms have many of the same amino acid sequences, they would be (more, less) related to each other.

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