Evolution, Viruses, Natural Selection

Structural adaptations help organisms survive in various environments. Which of these is not an example of a structural adaptation?

• The harmless syrphid fly resembles the yellow jacket in coloring and body shape. 
• The leaf frog’s coloring and shape make camouflage on the forest floor possible. 
• Mole-rats have large teeth and claws which help them dig tunnels and escape predators. 
• A lizard finds a shady spot to escape the sun’s heat.

Penicillin is widely used to kill bacteria which cause disease. However, this drug does not affect as many species of bacteria today as it did when it was first discovered. Which statement describing this situation is false?

• Thousands of years were required for bacteria to become resistant to penicillin.
• The ability of bacteria to resist penicillin varies within a population. 
• Bacteria which are resistant to penicillin will survive exposure to the drug. 
• . Bacteria which are resistant to penicillin will produce penicillin-resistant offspring. 

Which of the following statements about mutations is false?

• Environmental factors including radiation and chemicals can cause mutations to occur. 
•  Enzymes in cells can fix mutations by replacing incorrect nucleotides with correct ones. 
• All mutations are harmful to both the organism and the species to which it belongs.
• Cancer is one result of DNA mutation. 

Within a fish species, variations exist in color, size, and the speed at which individuals can swim. Which variation would be least likely to be passed on to future generations of the species?

• . swimming speed which is less than that of predators
• color of markings which aid camouflage
• size which enables hiding among small rocks and in rock crevices
• reproduction by laying extremely large numbers of eggs 

A bear produces two offspring. One of the cubs is smaller than normal and has difficulty digesting food. Which statement comparing the two cubs is false?

• The larger bear cub is more likely to survive to reproductive age. 
•  The smaller bear cub is less likely to pass its genes on to another generation. 
• The larger bear is better adapted for survival in its environment. 
• d. Both bear cubs are equally likely to pass their genes on to the next generation.

Which of these statements about natural selection is true?

• a. Organisms which survive to reproduce can pass favorable variations on to offspring.
• Natural selection works on individuals, rather than a population of organisms. 
• All organisms within a species are genetically identical. 
• . Offspring can inherit traits of an organism which that organism develops during its life. 

What is one reason that pumpkins are more closely related to corn plants than to edible mushrooms? 

• Pumpkins and corn grow more slowly than mushrooms
• . Pumpkins and corn need less moisture than mushrooms. 
• Pumpkins and corn taste different than mushrooms. 
•  Pumpkins and corn both make their own food

Heidi Takashi is a farmer who grows corn. About 10 years ago, Ms. Takashi began spraying her fields with herbicide, a chemical that kills plants, to kill weeds in the corn field. For a few years the herbicide killed nearly all of the weeds in Ms. Takashi’s corn field. One year, Ms. Takashi noticed that some weeds were growing even after being sprayed with herbicide. The next year, even more weeds were still alive after herbicide-spraying.  Based on what you know about how organisms adapt to their environment, what is the most likely reason to explain the results of Ms. Takashi’s use of herbicide?

• The weeds underwent a mutation which led to a resistance to herbicide. 
• The weeds were new species of weeds. 
• The herbicide was still effective on Ms. Takashi’s weeds. 
• The herbicide underwent a chemical change. 

. Which kind of evidence led scientists to suspect that species may change over time?

• fossils of marine organisms that were found buried in the sides of mountains
• a recent theory stating that new organisms can only come from older organisms 
• experiments in which plants were crossbred to produce offspring with traits from each parent
•  sequential layers of fossils that have the remains of the most modern-looking organisms in the top layers

During a severe drought a dry lake was explored for fossils. The diagram below represents the fossils uncovered and the layers they were in. According to this information, this area was once a—

• forest that was replaced by a freshwater lake
• freshwater lake that was replaced by a desert
• saltwater sea that was replaced by a forest
• freshwater lake that was replaced by a forest