Fast Lizards, Slow Corals ■ 245THE QUESTIONS
The Basics
(^1) When two populations are reproductively isolated, what else
must occur for speciation to happen?
(a) gene flow
(b) genetic divergence
(c) coevolution
(d) convergent evolution
(e) none of the above
(^2) Traits that are inherited and improve an individual’s ability to
survive and reproduce are called traits.
(a) adaptive
(b) polymorphic
(c) biological
(d) sympatric
(e) allopatric
(^3) Prezygotic isolating mechanisms prevent hybrid offspring from
occurring between species because
(a) the resulting offspring are not fertile and cannot reproduce.
(b) the egg and sperm fuse and form a zygote, but it does not
survive.
(c) the egg and sperm do not ever meet or, if they do, cannot fuse
to form a zygote.
(d) all of the above
(^4) Which of the following reproductive isolating mechanisms prevents
mating because the two species are physically unable to mate?
(a) ecological isolation
(b) behavioral isolation
(c) mechanical isolation
(d) gametic isolation
(e) all of the above
● (^) Adaptive traits, or
adaptations, are inherited
characteristics that improve
an individual’s chances of
surviving and reproducing in a
specific environment.
● (^) Natural selection leads to
adaptation, genetic changes
that improve the reproductive
success of organisms in
their environment over time.
Adaptation does not produce
“perfection.”
● (^) According to the biological
species concept, a species is
a group of populations that
interbreed and can produce
live and fertile offspring.
● (^) The process of speciation,
one species splitting into
two or more species, is the
by-product of reproductive
isolation and genetic
divergence between
populations.
● (^) Allopatric speciation occurs
when populations of a species
become geographically
isolated, limiting gene
flow and making genetic
divergence more likely.
● (^) Speciation that occurs
between populations lacking
geographic isolation is called
sympatric speciation.
● (^) In ecological isolation, two
closely related species in the
same area are reproductively
isolated by slight differences
in habitat.
● (^) When adaptive traits of one
species evolve in concert
with adaptive traits in
another species, coevolution
has occurred.
● (^) Reproductive isolating
mechanisms can be
prezygotic barriers (before
zygote formation) or
postzygotic barriers (after
zygote formation).