Chapter 18 · Eubacteria Kingdom Archaebacteria Eukaryotic Prokaryotic cells cells Important...
Transcript of Chapter 18 · Eubacteria Kingdom Archaebacteria Eukaryotic Prokaryotic cells cells Important...
Key Concepts
•How living things are organized for study
•What dichotomous classification is
•What binomial nomenclature is
•What Linnaeus’s system of classification is
18-1 Interest Grabber 1. Consider the task facing early biologists who
attempted to organize living things. How might they have begun?
2. Suppose that you have been given a green plant, stringy brown seaweed, a rabbit, a mushroom, a worm, and a grasshopper. You’ve been asked to organize these things into categories that make sense. How would you do it?
3. Decide on your categories and write each on a sheet of paper. Next to each category, write the defining characteristics of that category. Then, write in the organisms that fall into each category.
18–1 Finding Order in Diversity
Why Classify?
Assigning Scientific
Names
Early efforts at
naming organisms
Binomial
nomenclature
Linnaeus’s System of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Q: What is this animal called?
•Confusing common
names
• Panther
• Puma
• Mountain Lion
• Catamount
• Cougar
A: All of the Them! •Common Name depending on location
• Panther
• Puma
• Mountain Lion
• Catamount
• Cougar
•Scientific Name • Puma concolor
(formerly Felis concolor – changed in 1993)
Note – in Scientific Name, only the first term is capitalized
Section 18-1
Kingdom
Phylum
Class
Order
Family
Genus
Species
Linnaeus’s System of
Classification
You need to know these!
Think of a mnemonic
device to help you
remember the order!
“Please Excuse My Dear
Aunt Sally”
“King Phillip Cuts Open
Five Green Snakes”
Choose something that
has meaning to you
“Kings Play Colorado On
Friday. Go! Score!”
Section 18-1
Kingdom
Phylum
Class
Order
Family
Genus
Species
Linnaeus’s System of
Classification
Kingdom – a group of related phyla
**Linnaeus only recognized two kingdoms
– Plant & Animal**
Phylum – a group of related classes
Class – a group of related orders
Order – a group of related families
Family – a group of related genera
Genus – a group of related species
Species
Scientific name is always “Genus species”
Grizzly bear Black bear Giant
panda
Red fox Abert
squirrel
Coral
snake Sea star
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
GENUS Ursus
SPECIES Ursus arctos
Section 18-1
Classification
of
Ursus arctos
18-2 Interest Grabber One Big Family?
How can you determine if one organism is closely related to another? It may seem easy, but it isn’t, and looks are often deceiving. For example, roses and orchids are both flowering plants, but roses grow on bushes or vines and have thorns. Many orchids don’t even grow in soil—they can grow in trees! Rose and orchid blossoms look very different, and roses and orchids cannot produce hybrids, or offspring of crosses between parents with different traits.
18-2 Interest Grabber Do you think roses and orchids are closely
related? Explain your answer.
Now, apply the same logic to dogs. Different breeds of dogs—such as a Labrador retriever and a collie—can breed and produce offspring. So what is the difference between the rose-orchid combination and the Lab-collie combination?
What defines a species? Is appearance important? What other factors might be considered?
18-2 Modern Evolutionary
Classification
Which Similarities Are Most Important?
Evolutionary Classification
Classification Using Cladograms
Similarities in RNA and DNA
Molecular Clocks
CLADOGRAM
Appendages Conical Shells
Crab Barnacle Limpet Crab Barnacle Limpet
Crustaceans Gastropod
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
Section 18-2
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
Traditional Classification
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
CLADOGRAM
Appendages Conical Shells
Crab Barnacle Limpet Crab Barnacle Limpet
Crustaceans Gastropod
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
Section 18-2
Traditional vs. Cladogram
18-3 Interest Grabber
My Way or the Highway
Categories that are used to organize an
assortment of things should be valid. That is,
they should be based on real information.
However, categories should be useful, too.
Suppose that you are taking a survey of
traffic. You sit at the side of a busy
intersection and record the vehicles you
see in one hour.
18-3 Interest Grabber
What categories could you use to
organize your count of vehicles?
Look at your list of categories. Are all of
them equally useful?
Is there more than one valid and useful
way to organize living things?
18-3 Kingdoms and Domains
The Tree of Life Evolves
The Three Domain System
Domain Bacteria
Domain Archaea
Domain Eukarya
Protista
Fungi
Plantae
Animalia
Section 18-3
are characterized by
such as
and differing which place them in
which coincides with which coincides with
which place them in which is subdivided into
Living Things
Kingdom
Eubacteria Kingdom
Archaebacteria
Eukaryotic
cells Prokaryotic cells
Important
characteristics
Cell wall
structures
Domain
Eukarya
Domain
Bacteria
Domain
Archaea
Kingdom
Plantae
Kingdom
Protista
Kingdom
Fungi
Kingdom
Animalia
Cladistic Analysis Analysis of the order in
which derived
characteristics appeared
Cladogram – diagram that
shows the evolutionary
relationships among a
group of organisms based
on these characteristics
Derived Characteristics – a
characteristic that arises as
a lineage of organisms
evolves over time
DNA analysis determined evolutionary relationships
Similar genes are evidence of common ancestry
American Vultures and Storks are classified together based on DNA
Molecular Clocks Comparison of DNA -
determines when species diverged and began to evolve independently
“Neutral mutations” – insignificant genetic changes that accumulate at a steady rate are measured and compared from species to species
The degree of disimilarity indicates how long ago the two species shared a common ancestor
5 Kingdom
Classification
Monera – bacteria,
prokaryotes
Protista – unicellular, animal or plant like, such as algae
eukaryotes
Fungi – mushrooms
Eukaryotes, *previously classified as plants*
Plantae
eukaryotes
Animalia
eukaryotes
Six Kingdoms Monera Kingdom is too
general and composed of two distinct groups of bacteria Differences are as great
as those between animals and plants
Six Kingdom classification system separates monera into two kingdoms: Eubacteria Archaebacteria Protista
Fungi Plantae Animals
DOMAIN
KINGDOM
CELL TYPE
CELL
STRUCTURES
NUMBER OF
CELLS
MODE OF
NUTRITION
EXAMPLES
Bacteria
Eubacteria
Prokaryote Cell walls with
peptidoglycan
Unicellular
Autotroph or
heterotroph Streptococcus,
Escherichia coli
Archaea
Archaebacteria
Prokaryote Cell walls
without
peptidoglycan
Unicellular
Autotroph or
heterotroph Methanogens,
halophiles
Protista
Eukaryote Cell walls of
cellulose in
some; some
have
chloroplasts
Most unicellular;
some colonial;
some
multicellular
Autotroph or
heterotroph Amoeba,
Paramecium,
slime molds,
giant kelp
Fungi
Eukaryote Cell walls of
chitin
Most
multicellular;
some
unicellular
Heterotroph
Mushrooms, yeasts
Plantae
Eukaryote Cell walls of
cellulose;
chloroplasts
Multicellular
Autotroph
Mosses, ferns,
flowering
plants
Animalia
Eukaryote No cell walls
or chloroplasts
Multicellular
Heterotroph
Sponges,
worms,
insects, fishes,
mammals
Eukarya
Classification of Living Things
Key Characteristics of
Kingdoms & Domains
Three Domain System Classifications and divisions are based on evidence from
molecular clock models Organisms are grouped according to how long they
have been evolving independently (1) Domain Bacteria – Corresponds to Kingdom
Eubacteria unicellular, prokaryotes, peptidoglycan (protein that gives strength to the cell
wall; also important in binary fission (cell reproduction) (2) Domain Archaea – Corresponds to Kingdom
Archaebacteria unicellular, prokaryotes; live in the most extreme
conditions (low to no O2, brine pools, and volcanic hot springs)
No peptidoglycan; contain unusual lipids not found in any other living organisms
Three Domain System (cont.) (3) Domain Eukarya – all organisms that
have a nucleus (eukaryotes) Protista – members have greatest
variety, single celled and multi-cellular, some P/S like algae, some heterotrophic
Fungi – Heterotrophs, feed on dead or decaying matter, multicellular mushrooms and unicellular yeasts
Plants – multicellular P/S organisms, cell walls contain cellulose
Animals – multicellular heterotrophs, no cell walls