Botany – Bio 201
Lake Tahoe Community College
Spring Qtr.
Instructor: Sue Kloss
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Chapter 18
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I. The current diversity of life is a reflection of 3.5 billion years of life on earth
There are maybe 10 million species on earth;
A. Taxonomy
B. Evolution
C. Systematics
D. Phylogeny
II.
A population
A. A species
B. Type
C. Mating tests
III.
Taxonomy
A. Modern taxonomy
2. The binomial system
a. genus name
b. specific epithet
c. the species name is a combination of the genus and specific epithet
3. Genera are grouped into families, families into orders, orders into classes, classes into divisions,
divisions into kingdoms and kingdoms into domains.
4. The Plant Kingdom is divided into a number of Divisions
IV.
Evolution
A. Charles Darwin and Alfred Wallace
1. Darwin published “Origin of Species
2. Today, the theory of evolution underlies the science of biology
B. Darwin surmised that hereditary change occurred randomly
C. The major sources of variation are recombination’s of DNA in the formation of gametes
D. Endosymbiosis
1. chloroplasts were once free living cyanobacteria
2. mitochondria were once free living heterotrophic respiring bacteria
3. Merging DNA from different sources provides innovative opportunities to increase the
diversity of life.
E. The environment plays a role
1. natural selection.
2. differential reproduction
3. Natural selection can influence the composition of a population
4. speciation is the mechanism by which diversity can increase over time
Ch 18 – terms
taxonomy
evolution
systematics
phylogeny
population
species
hybrids
Linnaeus
binomial nomenclature
taxonomic hierarchy
Darwin
Wallace
endosymbiosis
cyanobacteria
natural selection
directional selection
stabilizing selection
disruptive selection
speciation
extinction
adaptive radiation
Ch. 18 - Lesson objectives:
1. Distinguish between systematics, taxonomy, phylogeny and evolution. What does "survival of the fittest" mean?
2. What is a species, and how is it generally defined? What are the problems with our current definitions? What is a
type specimen?
3. Describe our binomial system of naming organisms. Why do we use this system?
4. What is the the list of taxa (hierarchy) in our taxonomic system? Which is most specific? Least specific?
5. What are the forces that cause genetic variation? Give 2 examples of endosymbiosis that are thought to have
occurred long ago that changed the nature of life on earth.
6. Give an example of how evolution works, in your own words.
7. Draw graphs and provide examples to explain the meaning of the following types of natural selection - directional,
stabilizing and disruptive.
8. Describe 3 different methods of speciation.
9. Describe the 3 characteristics necessary in a biological system for natural selection to occur.