Evolution

Exploring the changes in populations over time that have brought us to the world we see around us, and understanding that evolution is still happening.

Chapters:
  • Environmental Science

  • Why Do Animals Survive or Die?

    Natural selection means that there are random differences in characteristics that organisms inherit from their parents. These characteristics may give individuals an advantage or disadvantage compared to others in surviving and reproducing. The advantaged offspring are more likely to survive and reproduce. In this way, there will be more of the organisms with advantageous characteristics. When an environment changes, characteristics that give an organism an advantage may change.

  • Forensics

  • Who Came Up With Evolution?

    Describe historical scientific developments that happened in evolutionary thought. For example, Lamarck and Darwin and Mendelian Genetics.

  • The Body

  • How Can You Tell Evolution Is Happening?

    Recognize that a change in gene frequency (the number of organisms that have a gene) in a population over the course of years is an important aspect of biological evolution.

  • How Do We Name Organisms?

    Biological classification represents how organisms are related with species being the most specific part. Biologists arrange organisms into a hierarchy of groups and subgroups based on similarities and differences, which have to do with how closely related they are.

OGT Questions:

  1. A student is studying several species that belong to the plant kingdom. Which two are most closely related?

    1. Ficus benjamina and Ficus lyrata
    2. Castilla elastica and Ficus elastica
    3. Bromus japonicus and Ipomoea violacea
    4. Fermaldia pandurata and Ficus pandurata
  2. The following diagram is found in an evolutionary biology textbook.

    Branching Tree Diagram

    This branching tree diagram is most likely used to represent the theory that suggests

    1. new species arise throughout time following rounds of mass extinction.
    2. all species share a common ancestor and that change occurs through time.
    3. speciation occurs very quickly with long periods of no change in between.
    4. all species originated during the same period and some have subsequently gone extinct.

    Use the following to respond to questions #3 – 5:

    The monarch is a bright orange butterfly with black stripes. It acquires toxins from the milkweed plants it eats as a caterpillar. Adult monarchs retain these chemicals. Experiments have shown that blue jays that eat poisonous monarchs become sick within 15 to 30 minutes. The viceroy is also an orange, black-striped butterfly, which is difficult to distinguish from a monarch. Viceroy larvae consume primarily non-toxic poplar or willow tree leaves.

    Butterfly Species

    Scientists have long suggested that viceroys have avoided predation by mimicking the monarch’s coloration pattern. New evidence indicates that this may not be the case. Descriptions of two sets of experiments with monarchs and viceroys are given below.

    Experiment 1 (1958): Blue jays that were raised in captivity were offered viceroys. The hungry jays devoured the viceroys. The same jays were offered monarchs. After eating one or two monarchs, the blue jays refused to eat monarchs or viceroys. All butterflies’ wings were intact when given to the birds.

    Experiment 2 (1991): Researchers fed the wingless abdomens of monarch, viceroy, queen, and non-toxic control butterflies to red-winged blackbirds and monitored the percentage of each type eaten. While 98% of control butterflies and 70% of queen butterflies were eaten, only 40% of viceroys and 40% of monarchs were eaten.

  3. The diagram below shows a partial classification scheme for monarch and viceroy butterflies.

    Butterfly Classification

    Based on this diagram, monarchs and viceroys belong to the same

    1. Genus
    2. Family
    3. Species
    4. Subfamilies
  4. What statement regarding the similarities between monarchs and viceroys best agrees with Charles Darwin’s theory of natural selection at the time of its publication in 1859?

    1. Monarch butterflies are an older species than viceroy butterflies.
    2. Similarities between monarch and viceroy butterflies result from their diets.
    3. Viceroy butterflies avoid predation due to their resemblance to monarch butterflies.
    4. Variations in DNA sequences are responsible for the similarity between monarch and viceroy butterflies.
  5. A scientist studying a large population of a particular species of bird concludes that monarch butterflies are toxic to that bird species. However, upon studying a second, smaller population of the same bird species, he discovers that the second population is able to eat monarchs without becoming sick.

    How could the scientist best explain his findings?

    1. The larger bird population has a small gene pool.
    2. Monarchs are only toxic if eaten in large quantities.
    3. Genetic drift has occurred in the smaller population.
    4. Natural selection has increased populations of non-toxic butterflies.