Biology 2 - Review 1

Scientists observe that the forelimbs of humans, bats, whales, and cats share the same basic bone pattern (humerus, radius, ulna, carpals, metacarpals, and phalanges), yet they perform different functions such as grasping, flying, swimming, and walking. What does this observation provide strong evidence for?

  

• Convergent evolution through environmental adaptation

• Vestigial organs with no present function

• No evolutionary relationship among organisms

• Homologous structures indicating common ancestry

    

In deeper rock layers, only simple marine organisms are found, while more recent layers contain complex terrestrial animals. What conclusion can best be drawn?

                                          

• Life forms changed gradually over time

• Marine organisms evolved from land animals    

• All organisms appeared at the same time
                           

•   Complex organisms existed before simple ones

Humans have a small bone at the base of the spine called the coccyx, or tailbone, which no longer functions as a tail. Why is the human tailbone considered a vestigial structure?

                                       

• It prevents the growth of additional vertebrae

• It is a reduced remnant of an ancestral tail

•   It evolved recently for upright posture  

• It helps humans maintain balance while running                 

Which of the following best explains why stromatolites are important in understanding early life?

• They provide evidence of early vertebrate evolution.

• They show the earliest emergence of eukaryotic cells.

• They are fossil evidence of photosynthetic prokaryotes.

• They record the first appearance of multicellular animals.

What does the presence of cyanobacteria in early fossils suggest about Earth’s history?

 

• It marks the origin of multicellular eukaryotic life

• It shows the initial evolution of vertebrate animals in oceans

• It records the first appearance of organisms with hard skeletons

• It indicates the start of oxygen accumulation in the atmosphere

Why does natural selection lead to evolution in populations?

• Because it causes random mutations in individuals.

• Because it favors individuals with traits that aid survival.

• Because it randomly selects some individuals to survive.

• Because it removes individuals with less favorable traits.

The pentadactyl limb (five-fingered limb) is found in vertebrates such as humans, dolphins, and birds, although it performs different functions in each species. What does this similarity in structure suggest?

•   Convergent evolution due to similar selective pressures.
    

•   A common evolutionary ancestor with modifications over time.

•    That the species evolved independently of each other.

    

• Evolution through random mutation.                                 

Which of the following situations shows artificial selection?

  

 

 

  

• cultivations of new varieties of rice plants

•   elongated neck giraffe

• the different finches by Darwin in the Galapagos Islands

• susceptibility testing of microorganisms against different antibiotics

An island’s entire population of a species of butterfly are descended from just two parents. These were introduced from the mainland. Which of the following statements about species of butterfly compared with that of the mainland is correct?

 

• The population shows more genetic variation than the mainland.

• The population will adapt more slowly to changes in the environment.

• The population is less likely to be affected by disease than the mainland.

• The population shows more visible differences in traits than the mainland.

   

Wallace’s work on biogeography helped to support which of the following ideas?

• Geographic isolation leads to speciation

• Species are fixed and unchanging over time

• Evolution only occurs in temperate climates

• Species change through direct environmental influence only