AP Biology Reading Guide
CHAPTER 24: The Origin of Species
Directions
1) Before you read the chapter, decide whether you think each statement is true or false. Circle your
choice. If you are uncertain, write in a question mark and circle it.
2) As you read the chapter, identify whether each statement is true or false according to what you have
read. Circle the answer and note the evidence in complete sentences.
3) Was your thinking changed or reinforced by what you read? If so, in what way?
4) Be prepared to share your answers with the class.
Before
Reading
True
False
Statement
True
False
2. Although particularly helpful in thinking about speciation processes, the
biological species concept has some major limitations. For instance, it cannot be
applied to organisms that are known only as fossils or to organisms that reproduce
only asexually. Thus, scientists maintain alternative species concepts, such as the
morphological species concept, that are useful in various contexts.
Evidence:
True
False
True
False
3. Allopatric speciation may occur when two populations of one species become
geographically separated from each other. One or both populations may undergo
evolutionary change during the period of separation. Should they come into contact
once more, they may be separated by the prezygotic and postzygotic isolating
mechanisms that have accumulated.
Evidence:
True
False
True
False
4. A new species can originate while remaining in a geographically overlapping area
with the parent species. In particular, many plant species have evolved sympatrically
through polyploidy (deletions of the chromosome number). Autopolyploids are
species derived this way from one ancestral species. Allopolyploids are species with
True
False
1. A biological species is a group of populations whose individuals have the
potential to interbreed and produce fertile offspring with each other and members of
other species. The biological species concept emphasizes reproductive isolation
through prezygotic and postzygotic barriers that can result in separating the gene
pools of different populations.
Evidence:
After
Reading
True
False
multiple sets of chromosomes derived from different species. Sympatric speciation
can also result from the appearance of the new ecological niches and from
nonrandom mating in polymorphic populations.
Evidence:
True
False
5. In allopatric speciation, a reproductive barrier isolates a subset of a population
without geographic speciation. In sympatric speciation, a new species forms while
geographically isolated from its parent population.
Evidence:
True
False
True
False
6. Adaptive radiation can occur when a population encounters a multiplicity of new
or newly available ecological niches. This may happen during colonization of a new
environment, such as newly formed volcanic islands, or after an environmental
change that has resulted in mass extinctions of other species in an area.
Evidence:
True
False
True
False
7. The explosion of genomics is enabling researchers to identify specific genes
involved in some cases of speciation.
Evidence:
True
False
True
False
8. Eldredge and Gould’s gradual change model draws on fossil evidence showing
that species change most as they arise from an ancestral species, after which they
undergo relatively little change for the rest of their existence. This model contrasts
with a model of punctuated equilibrium throughout a species’ existence.
Evidence:
True
False
True
False
9. Most novel biological structures evolve in many stages from previously existing
structures. Some complex structures, such as the eye, have had similar functions
during all stages of their evolution. The most important functions of others, such as
feathers, have changed.
Evidence:
True
False
True
False
10. Many large evolutionary changes have been associated with mutations in genes
that regulate development. Such changes can affect the timing of developmental
events (heterochrony) or the spatial organization of body parts. Some of these
changes result from mutational changes in homeotic genes and in the genes that
regulate them.
Evidence:
True
False
True
False
11. Long-term evolutionary trends may arise because of adaptation to a changing
environment. In addition, according to the species selection model, trends may
result when species with certain characteristics endure longer and speciate more
often than those with other characteristics.
Evidence:
True
False