Biology Test Preparation Practice

    Genetic Variation And Natural Selection


    Base your answers to questions 7 on the information below and on your knowledge of biology.

    The Galapagos pink land iguana, Conolophus marthae (C. marthae), is native to only one of the Galapagos Islands. Its entire range is currently limited to Wolf Volcano on Isabella Island. The iguana was first discovered on this island in 1986. Genetic studies of the animal began sometime later, and it was identified as a species separate from other iguana populations on the Galapagos in 2009. Its population might have been as high as 100 in 1986, but now there might be as few as 10 of the animals left alive.

    Other evidence indicates that this species could have diverged from another line of iguanas about 5.7 million years ago. After that, the other line of iguanas diverged into two other species, C. pallidus and C. subcristatus.


    Base your answer to question 10-14 on the information below and on your knowledge of biology.

    New varieties of organisms have resulted from human activities. These organisms have often led to problems in modern society. Two of these new varieties are listed below.

    Antibiotic-resistant bacteria Pesticide-resistant insects


    Base your answers to questions 16 on the information below and on your knowledge of biology.


    Today’s elephants are the result of a long process of evolution. Over millions of years, small changes were passed from one generation to the next. The first fossil elephant species were small, but over time, they increased both in size and weight. The three species alive today are the sole survivors of a once much more widespread group.



    Base your answers to questions 18 on the information below and on your knowledge of biology.

    Project Frozen Dumbo – Saving the Elephant Population Means Using Special Breeding

    Over the last 10 years, 70 percent of Africa’s wild elephant population has been killed off. The main cause is ivory poaching, in which elephants are slaughtered for their valuable tusks. At the same time, efforts to breed captive zoo elephants have not been very successful.

    Now there is some good news. At zoos in Austria and England, two baby elephants were born, using sperm from South African wild elephants. For the first time, elephant sperm gathered in the wild was frozen and given to zoos. Two female zoo elephants were artificially impregnated with the sperm and went on to deliver calves. …

    Source: Saving the Elephant Population Means Using Special Breeding, Pittsburgh Post-Gazette, 8/21/14


    Base your answers to questions 19 on the information below and on your knowledge of biology.

    Female Shark Reproduced Without Male DNA, Scientists Say

    A hammerhead shark that gave birth in a Nebraska aquarium reproduced without mating, a genetic analysis shows.

    This form of asexual reproduction, called parthenogenesis, has been found in other vertebrate species, including some snakes and lizards. But this is the first time it has been documented in a shark.…

    Instead, the female shark’s own genetic material combined during this process of cell division that produces an egg. A cell called the secondary oocyte, which contains half the female chromosomes and normally becomes the egg, fused with another cell called the secondary polar body, which contains the identical [amount of] genetic material….

    Robert E. Hueter, director of the Center for Shark Research at the Mote Marine Laboratory in Sarasota, Fla., said the finding helped fill a gap in understanding parthenogenesis, which has been found to occur in most vertebrate lines except mammals, and until now, cartilaginous fishes like sharks….

    “It’s a last-resort tactic that animals use when they absolutely can’t find another mate,” Dr. Hueter said.

    Source: Henry Fountain, The New York Times, May 23, 2007