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CLASSIFICATION
How can you classify fruits?
Procedure
1.
2.
3.
4.
Obtain five different fruits. Use a paring knife to cut each fruit open and examine its structure. CAUTION: Use caution
with sharp instruments.
Construct a table with five rows and four columns. Label each row with the name of a different fruit.
Observe each fruit and choose four characteristics by which you can tell the fruits apart. Label the columns in your table
with these four characteristics.
Record a description of each fruit in your table.
Think About It
1.
2.
I.
Observing What characteristics did you use to describe the fruits?
Classifying Based on your table, which fruits are most closely related? Explain.
Finding order in diversity
- scientists named 2.5 million species
- estimated 4-30 million additional species yet to be discovered
i. Why classify
1. To avoid confusion caused by common names, biologists assign each species a
scientific name
2. To study the diversity of life, biologists use a classification system to name
organisms and group them in a logical manner
3. Taxonomy –
ii. Assigning scientific names
1. ______________________________
a. Each species is assigned a two-part scientific name
b. Written in italics, first word is capitalized, second is lower case
i. Ex. Grizzly bear Ursus arctos
1. Ursus –
2. arctos –
a. there are 5 other types of bears in the same
genus Ursus
iii. Linnaeus’s systen of classification
1. Taxon –
i. Linnaeus’s system of classification uses
seven taxonomic categories. They are –
from smallest to largest – species, genus,
family, order, class, phylum and kingdom
ii. Figure 18-5
SECTION ASSESMENT
1.
Key Concept How are living things organized for study?
2.
Key Concept Describe the system for naming species that Linnaeus developed.
3.
Key Concept What are the seven taxonomic categories of Linnaeus’s classification system?
4. Why do scientists avoid using common names when discussing organisms?
5. Critical Thinking Applying Concepts Which category has more biological meaning—all brown birds or all
hawklike birds? Why?
II.
MODERN EVOLUTIONARY CLASSIFICATION
i. Problems with traditional classification
1. vultures american, african and asian
a. american habit of urinating on legs to cool themselves, same as storks.
African and asian vultures do not.
ii. Evolutionary classification
Overhead of humans and apes
1. guided by evolutionary theory, biologists new group organisms into categories
that represent lines of evolutionary descent, not just physical similarities
2. _______________________ – method of grouping organisms according to how
recently descended they are from a common ancestor.
3. traditional classification – figure 18-7
4. Classification using cladograms
a. Cladistic analysis identifies and considers only characteristics that are
evolutionary innovations, new characteristics that arise as lineages evolve
over time
b. ______________________ – unique features that appear in some
organisms but not others
c. __________________ – branching diagram used to show the diverging
sequence in which key evolutionary changes occurred
QUICK LAB PG.
453
How is a cladogram
constructed?
Procedure
1.
2.
Identify the organism in the table that is least closely
related to the others.
Use the information in the table to construct a cladogram
of these animals.
Analyze and Conclude
1. Analyzing Data What trait separates the least closely
related organism from the other animals?
2. Classifying List the animals in your cladogram in order of distance from the least closely related organism.
3. Drawing Conclusions Does your cladogram indicate that lizards and humans share a more recent common ancestor
than either does with an earthworm? Explain.
4. Inferring Where would you insert a frog if you added it to the cladogram? Explain your answer.
iii. Similarities in RNA and DNA
1. all living organisms use RNA and DNA the same way
2. Common ancetry evident in genes
a. The genes of many dissimilar organisms show important similarities at the
molecular level. These similarities can be used as critieria for
classification
b. Common gene structure indicator of common ancestory
i. Similar common feature of all living cells – the ribosome – the
cellular “protein factor”.
ii. Gene that codes for myosin found in muscles in humans
intercellular parts to move in yeast
iv. Molecular clocks
1. molecular clock – model used to estimate the length of time that 2 species have
been evolving independantly based on mutations in an organisms DNA
Section assesment 1-5 pg. 455
1. Key Concept How is information about evolutionary relationships useful in classification?
Key Concept How are genes used to help scientists classify organisms?
2.
3. What is the principle behind cladistic analysis?
4. Describe the relationship between evolutionary time and the similarity of genes in two species.
5. Critical Thinking Applying Concepts How have new discoveries in molecular biology affected the way in which we
classify organisms compared with the system used by Linnaeus?
Constructing a Chart
Draw a cladogram of a manufactured item, such as an automobile or a household item, that has changed over the years. Label
derived characters that appeared as new models arose. For example, automobiles came to have electronic fuel injection and
antilock brakes.
III.
Kingdoms and Domains
i. The tree of life evolves
1. in the beginning…… then……. The six kingdom system of classification includes the
kingdoms ANIMALIA, PLANTAE, FUNGI, PROTISTA, AND 2 BACTERIAL
KINGDOMS EUBACTERIA AND ARCHAEBACTERIA.
ii. The 3 domain system
1. ______ – is a more inclusive category than any other – larger than a kingdom.
2. The three domains are: the domain of bacteria, which corresponds to the
kingdom ________________; the domain archae, which corresponds to the
kingdom __________________; and the domain ____________, which is
composed of animals, plants, fungi, and protists.
CLASSIFICATION OF LIVING THINGS
DOMAIN
KINGDOM
CELL TYPE
NUMBER OF
CELLS
MODE OF
NUTRITION
EXAMPLES
3. Bacteria
a. Domain of unicellular prokaryotes that have cell walls containing
peptidoglycans
4. Archaea
a. Domain of unicellular prokaryotes that have cell walls that do not contain
peptidoglycans
5. Eukarya
a. Domain of all organisms whose cells have nuclei, including protists, plants,
fungi and animals
i. Protistsa – kingdom composed mainly of single – celled eukaryotes:
includes all eukaryotes that are not classified as plants, animals or
fungi
ii. Plantae – kingdom of multicellular photosynthetic autotrophs that
have cell walls containing cellulose
iii. Fungi – kingdom composed mainly of saprophytes, which obtain
energy and nutrients from dead and organic matter
iv. Animalia – kingdom of multicellular eukaryotic heterotrophs whose
cells do not have cell walls
Section assesment 1-3, 5
1.
Key Concept What are the six kingdoms of life as they are now identified?
2.
Key Concept What are the three domains of life?
3. Why was the kingdom Monera divided into two separate kingdoms?
4. Why might kingdom Protista be thought of as the “odds and ends” kingdom?
5. Critical Thinking Classifying Which kingdoms include only prokaryotes? Which kingdoms include
only heterotrophs?