Download Section: 1.3 Name: Section Title: Microevolution

Section: 1.3
Name:
Section Title: Microevolution
Opening Activity:
Latin Root Word: micro Review of Old Information: NONE
New Information:
I. What is Microevolution?
• Microevolution -populations and species change through time resulting from relatively
_______________ genetic variations
• Speciation - the process of new species forming from old species. Driven by ________________
and _______________ isolation.
II. Rates of Speciation:
1. Gradualism: gradual evolution, new species develop over ______________ periods of time.
2. Punctuated Equilibrium: long, stable periods of time separated by _______________ changes.
III. What causes Microevolution?
•
•
•
•
______________
______________
______________
______________
lV. Mutation
• A change in _______________ structure that causes the expression of a different trait which
changes the gene frequency.
V. Migration
• _______________ - gene frequencies changing by individuals moving into a population
• _______________ - gene frequencies changing by individuals moving out of a population
VI. Genetic Drift
• shift in gene frequencies as a result of _______________ _______________ which changes
overall genes in the population (i.e. wildfire, flood, drought, etc.)
VII. Natural Selection
• Stabilizing Selection :
• Directional Selection :
• Disruptive Selection :
• Sexual Selection :
Diagram:
Stabilizing Selection
Disruptive Selection
Activity:
1. What is the definition of evolution?
a. What do you think the prefix “micro” means?
b. Therefore, how would you define microevolution?
2. _____A small change in gene frequencies to a population overtime is called
a. Macroevolution
b. Speciation
c. Microevolution
d. Migration
3. _____Which of the following is not a type of natural selection?
a. Disruptive selection
b. Directional selection
c. Rotational selection
d. Stabilizing selection
4. _____Which of the following is not a cause of natural selection?
a. Speciation
b. Mutation
c. Migration
d. Genetic Drift
e. All of the above
5. _____Which of the following is not an assumption of Hardy Weinberg Equilibrium
a. There is no mutation
b. There is no migration
c. Individuals mate randomly
d. There is no natural selection
e. None of the above
Directional Selection
6. _____The ability of an organism to survive, reproduce, and pass on its traits is called
a. Speciation
b. Hardy Weinberg Equilibrium
c. Fitness
d. Genetic Drift
7. _____A population of beetles reproduces and the parent generation has 75% brown genes and 25% green
genes. Due to random luck the offspring of the population has 71% brown genes and 29% green genes. This
phenomenon is called ______?
a. Mutation
b. Genetic Drift
c. Speciation
d. Sexual selection
8. _____There is a population of peppered moths that exist in an industrialized area where soot has covered areas
of plants in the environment. Peppered moths can be all white, white with black spots, and all black. Which of
the three peppered moths would be considered most fit for that environment?
a. White
b. Spotted
c. Black
d. None of the above
10. _____Natural selection where organisms with either extreme expression for a particular trait are more likely to
survive is known as ______________.
a. Directional selection
b. Disruptive selection
c. Stabilizing selection
11. _____Speciation is driven by
a. Species area effect
b. Catastrophism
c. Geographic and reproductive isolation
d. Uniformitarianism
12. _____Gradualism states that new species develop over
a. Disruptive selection
b. Long periods of time
c. Quick changes
d. Stabilizing selection
13. The mechanisms for microevolution: mutation, migration, genetic drift, and natural selection. These mechanisms
cause a change in gene frequency in a single population which is the definition of microevolution. Explain each
mechanism in you own words using complete sentences.
a. Mutation:
b. Migration:
c. Genetic Drift:
d. Natural Selection:
14. The process of a new species developing through microevolution from a pre-existing species is called
________________________.
15. There are four types of natural selection: stabilizing selection, directional selection, distributive selection, and sexual
selection. Match the description of the four types of natural selection with the following pictures.
Stabilizing selection is when individuals with an
average trait have the greatest chance of
survival.
1 __________
Directional selection is when individuals with one
of the more extreme traits are more likely to
survive.
2 __________
Sexual selection is when females choose males
to mate with bases on certain traits.
3 __________
Disruptive selection is organism with either
extreme trait have a greater chance of survival.
4 __________