Scientists study the evolutionary relationships of species to better understand the history of life on Earth.
Describe two methods that scientists can use to determine whether two species (modern or extinct) are closely related

• Two methods of showing relatedness are studying skeletal structure and comparing DNA sequence.  Related animals share common skeletal structures that usually have similar shapes.  Similar DNA sequences can also show a degree of relatedness between different organisms.
• By comparing fossils and DNA sequences.
• Scientists can tell if species are related by studying their bone structure, which can be similar in shape and function.  Scientists can also study hunting, breeding, and communication techniques; which show us that different organisms are able to survive in similar habitats.
• By looking at their ancestors to see if they are related and by examining their scientific name.

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The graph shows how a Serengeti buffalo population changed over a period of years. During this time period, the buffalo were affected by the rinderpest virus, a debilitating disease with a high mortality rate. However, within five years, the virus was eliminated.
What was the ecosystem’s carrying capacity for buffalo, based on the graph, once rinderpest was eliminated?

• 35,000
• 60,000
• 65,000
• 55,000

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NGSS.HS-LS2-1

The table compares structures found in several groups of photosynthetic organisms. The presence of a structure is symbolized by a (+) symbol, while the absence of a structure is symbolized by a (-) symbol. 
Using the data in the table, determine where on the cladogram some of the structures evolved. Place the structure number into each lettered box. 

• A. 5, B. 4, C. 2, D. 1
• A. 1, 2. B, 3. C. 4, D. 4
• A. 2, B. 5, C. 4, D. 3
• A. 3, B. 5, C. 1, D. 2

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A scientist isolates a number of non-photosynthetic prokaryotes.  Which structure would be found in these cells?

• cell wall
• golgi 
• chloroplast
• nucleus

Oxygen depletion, also known as hypoxia, is one result of runoff from over-fertilized lawns or farmland. After heavy rains, nutrient-rich water enters the local aquatic environment, causing a series of events to occur within the ecosystem. Some events caused by nutrient-rich runoff entering a lake ecosystem are shown. Indicate the sequence letters into the correct order of these events.

• A, B, C, D
• D, A, C, B
• B, D, A, C
• D, B, C, A

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A strand of DNA is exposed to intense heat. Which of these best describes what will happen to the strand of DNA?

• The chemical bonds that hold the two strands together will be broken and the strands will separate.
• It will cause the DNA to coil up into a tighter double helix.
• It will cause uracil to replace thymine.
•  Nothing will happen, DNA is not affected by extreme temperature changes.

A scientist is examining a pedigree that includes several generations of an organism that has XX/XY chromosome sex determination.  
Which pattern of inheritance would support the hypothesis that the trait being studied is a recessive sex-linked trait found on the chromosome?

• The trait is only expressed in males with a father who has the trait.
• The trait is expressed in half of the males and half of the females.
• The trait is mostly expressed in males with a maternal grandfather with the trait.
• The trait is mostly expressed in females with a paternal grandmother with the trait.

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NGSS.HS-LS3-1

You are examining at a slide of cells through a microscope and notice that the cell has a cell membrane, a nucleus, and chloroplasts.  What type of cell are you examining?

• prokaryotic
• plant 
• animal
• bacterial

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NGSS.MS-LS1-1

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The table shows sample cells taken from two individuals of the same species.  DNA from each cell is analyzed using gel electrophoresis.  
Which prediction would be supported by the results of the gel electrophoresis analysis?

• Cell 1 from individual A will have an identical banding pattern to Cell 1 from Individual B
• Cell 1 from individual A will have an identical banding pattern to Cell 2 from Individual A
• Cell 1 from individual A will have a different banding pattern to Cell 3 from Individual A.
• Cell 1 from individual A will have a different banding pattern to Cell 4 from Individual A.

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NGSS.HS-LS3-1

Which of these would lead to a lower rate of photosynthesis in a plant?

• A decrease in the amount of available oxygen in the atmosphere.
• A decrease in the amount of available carbon dioxide in the atmosphere.
• A decrease in the average year long temperature.
• An increase the amount of salt water available world wide.

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NGSS.HS-LS2-5