Evolution Day 6
Use the Speciation presentation to answer the following questions.
What must organisms be able to do in order to be considered members of the same species? (slide 2)
2. Define reproductive isolation. (slide 3)
3. Define prezygotic barriers and give 4 examples of this type of barrier. (slide 4)
a. Definition:
b. Examples:
4. Define postzygotic barriers and give 3 examples of this type of barrier. (slide 5)
a. Definition:
b. Examples:
5. What type of barrier (pre or post & the specific type) is preventing reproduction in the following examples:
(slide 6)
a. Snakes
b. Skunks
c. Birds
d. Snails
6. What type of barrier (pre or post & the specific types) is preventing reproduction in the following examples:
(slide 7)
a. Sea urchins
b. Salamander
c. Mule
d. plant
7. Identify the following scenarios as “pre” or “post” then give the specific type (habitat, temporal, behavioral,
mechanical, gametic, reduced hybrid viability, reduced hybrid sterility, or hybrid breakdown) – slides 5, 6, & 7
a. 2 salamander speces breed in the same area. The first breeds from late February through March. The
second does not mate until late March or early April.
b. 2 species of mice are mated in the lab and produce fertile hybrid offspring, but offspring of the hybrids
are sterile.
c. When fruit flies from two species are crossed in the lab, their offspring are unable to produced eggs and
d. A zoologist observed two land snails of different species that were trying to mate with little success
because they apparently did not “fit” each other.
e. Male fiddler crabs wave their large claws to attract the attention of females. Each species has a slightly
different wave.
When different species of tobacco plants are crossed in a greenhouse, the pollen tube usually bursts
before the eggs are fertilized.
g. Blackjack oak grows in dry woodlands, and scrub oak grows in dry, rocky, open areas. Pollen of one
species seldom pollinates the other.
h. The tiglon offspring of a lion and a tiger are often weak and unhealthy.
8. What do reproductive barriers lead to? (slide 8)
9. What are the two types of speciation? (slide 9)
a. Type 1
b. Type 2
10. Define allopatric speciation. (slide 10)
11. Using your own words explain what occurs during allopatric speciation. (slide 11)
12. Explain the example of allopatric speciation shown on slide 12.
13. Define sympatric speciation. (slide 13)
14. Define polyploidy and explain how it is an example of sympatric speciation. (slide 14)
15. How does habitat differentiation lead to sympatric speciation? (slide 15)
16. How does sexual selection lead to sympatric speciation? (slide 16)
17. Complete the table below using the information from slide 17.
Allopatric Speciation
Geographic Isolation
Sympatric Speciation
Isolated populations evolve
No geographic isolation
Populations evolve differences
while in the same area
18. Compare and contrast punctuated equilibrium and gradualism using the information from slide 18.
Punctuated Equilibrium
19. Describe how the two different evolutionary trees differ for punctuated equilibrium and gradualism. (slide 19)

Evolution Day 6 Name: Use the Speciation presentation to answer