life on earth
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Life On Earth. Do Now: Scientists estimate that there may be as many as 100,000,000 different species of organisms on Earth. Of these, about 1 x 10 7 have been identified. What % of species have not been identified? . Today’s Big Ideas. - PowerPoint PPT PresentationTRANSCRIPT
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Life On Earth
Do Now:Scientists estimate that there may be as many as 100,000,000 different species of organisms on Earth. Of these, about 1 x 107 have been identified. What % of species have not been
identified?
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Today’s Big Ideas• Taxonomy is the process of organizing and classifying organisms
into different groups.
• The highest level of organization is called a domain, and there are three: Domain Eukaryota, Domain Bacteria, and Domain Archaea.
• Domain Eukaryota includes the plant, animal, fungi, and protist kingdoms, because they are all made of Eukaryotic cells (with a nucleus.)
• There are two domains of prokaryotes (no nucleus): Bacteria and Archaea.
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Classifying Life
• Biologists classify organisms in two major ways:– Morphology = the structures and characteristics of
organisms– Phylogeny = the evolutionary history and
relationships of organisms
“morph” = “form”
“phylo” = “type, kind, race, or tribe”
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Morphological Classification Example
• Mollusks are animals that have an organ called a mantle that makes a shell.
• Organisms with one shell are called gastropods, organisms with a double shell are called bivalves.
gastropodbivalve
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Phylogenetic Classification Example• These bacteria are all
unicellular prokaryotes.
• The tree shown classifies the species according to DNA similarity
• The more similar the DNA of two species is, the more recently they shared a common ancestor.
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The Modern Classification Scheme
• The picture at right shows the classification scheme used to group similar organisms together.
• Notice how each group is made up of many of the smaller groups below it.
• In other words, as you go down the picture, the groups are more specific and include less organisms
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Hierarchy: An arrangement of items into groups “above,” “below,” or “at the same
level as” other groups.
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Hierarchy Example: Many Classes Make up One Phylum
• The phylum chordata includes all animals that have backbones
• There are many different classes of animals that have backbones, like class rodentia (rodents), class primates, etc. etc.
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Taxonomy = The practice of classification• Taxonomy is
the process or study of classification.
• A biological taxonomist is a scientist who specializes in classifying organisms
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The Top Level: Domain• Domain Eukaryota is where you belong. ALL
EUKARYOTIC CELLS HAVE A MEMBRANE-BOUND NUCLEUS. They often contain other internal membranes and membrane-covered organelles, like the ER, Golgi, mitochondria, chloroplasts, and others
• Domain Bacteria and Domain Achaea: ALL BACTERIA AND ARCHAEA CELLS ARE PROKARYOTIC AND DO NOT HAVE A MEMBRANE-BOUND NUCLEUS. They also don’t have membrane covered organelles, like mitochondria and chloroplasts. They differ from one another for biochemical reasons (like phospholipid chemistry)
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The Tree of Life, by DNA Similarity
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Taxonomy Activity
• Your group will receive 11 items classified in the family junkus.
• Your job is to divide family junkus into several genera (genuses).
• Each genus can then be divided into 1 or more “species” of organism
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Things To Include in Your Report• Unique “scientific names” of each
“species.”– Should be “latin.”– Each must be unique– Scientific names include genus and
species. Example: “Pencilum reddus.”
• A tree diagram showing the relationships of the genuses and species.
• Answers to questions – complete independently!