The Origin of Life Life originated 3.5-4.0 billion years ago! What came first: prokaryotic cells or...
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Transcript of The Origin of Life Life originated 3.5-4.0 billion years ago! What came first: prokaryotic cells or...
The Origin of Life
• Life originated 3.5-4.0 billion years ago!
What came first: prokaryotic cells or
eukaryotic cells?
Prokaryotes
• Prokaryotes dominated life on Earth from 3.5-2.0 bya!– The 1st actual cells
3.5 billion year old fossil of bacteria Modern bacteria
Chains of unicellular cyanobacteria
The Origin of Eukaryotic Cells
Bacteria were the starting point for all the life we have today!
How many species exist on Earth?
• We don’t know an exact number – MILLIONS
• More still waiting to be discovered!
How do we keep track of all of them?
Classifying Organisms
Devil Cat
Ghost Cat
Mountain Lion
Screaming Cat
Puma
Florida Panther
All the same species!
• There are at least 50 different names for the species of cat shown before.– Different places have different
names.
• Scientific name: Felis concolar– Why is it important to have
scientific names?
Scientific Names
• Give species an “official” name
• Come from “dead” languages – Latin or Greek
• We get the names from the way the organisms are classified.
Solenopsis invicta
TaxonomyClassifying Living Organisms
Taxonomy
• The science of classifying organisms– Show how organisms are
related– Provides a universal system
for identifying organisms– Provides scientific names
We use the Linnaean system for classifying organisms.
A good way to remember…
KingPhillipCameOverForGoodSoup
What is the order of the Linnaean classification system?
A. Kingdom, Phylum, Genus, Class, Order, Family, SpeciesB. Kingdom, Family, Phylum, Genus, Order, Class, SpeciesC. Kingdom, Phylum, Class, Genus, Order, Family, SpeciesD. Kingdom, Phylum, Class, Order, Family, Genus, Species
King Phillip Came Over For Good SoupKingdom, Phylum, Class, Order, Family, Genus, Species
Linnaean Classification
• System for classifying organisms by hierarchy - goes from broad to specific!
All Living Species
Animalia
Plantae
Fungi
Protista
Eubacteria
Archaebacteria
All living species can be broken down into 6 kingdoms:
1. Animalia2. Plantae3. Fungi4. Protista5. Eubacteria6. Archaebacteria
Each of these kingdoms can be broken down into phylums!
Human Linnaean Classification
Notice how we went from broad
categories to specific categories!
Kingdom Animalia contains many species!
Some animals have a backbone, some don’t.
Phylum Chordata (backbone) includes several mammals.
Some mammals are carnivores.
Several carnivorous mammals are bears.
Some bears are more closely related than others…
We’ve narrowed it down to a specific species!
Binomial Nomenclature
• Formal system for naming species– Latin or Greek– Italicized– Genus species
Turdus migratorius, or American Robin
What genus does the American Robin belong to?
Turdus!Remember that species get their
scientific names from their classification – Genus species
A. AmericanB. RobinC. TurdusD. Migratorius
Turdus migratorius
Which species are more closely related?
Polar & Grizzly Bear – they belong to the same genus!
A. Panda & Polar BearB. Polar Bear & Grizzly BearC. Grizzly Bear & Panda
Which of the following is true?
A. All animals are chordates.B. All felines belong to the
genus Panthera.C. All chordates are
mammals.D. All felines are carnivores.
Which category in the Linnaean System is the most specific?
A. PhylumB. FamilyC. ClassD. Genus
Genus!
33
Broad
Specificcopyright cmassengale