2Why do Scientists Classify? Imagine a grocery store…How are they organized?What would happen if they were not organized?How is your life organized?
3Why do Scientists Classify? Almost 13 billion known species of organismsNeed to keep organized! (Easier to study!)Classification the grouping of information or objects based on similarities.
4Why do Scientists Classify? Taxonomy is the science of grouping and naming organisms.Useful because:once classified, scientists will know a lot about an organism
5Early Classification Systems Aristotle (4th century B.C.)-observed animals-watched appearance, behavior, movement-fly, swim, and walk/crawl/run-observed similarities and differences-used differences to divide into smaller subgroups
6Linnaeus Carolus Linnaeus (1750s) -used observations as basis of his system-placed organisms based on observable featuresDevised naming system for organisms:Binomial Nomenclature
7Linnaeus Binomial Nomenclature- 2 part naming system -uses Latin words First name (genus); second name (species)Genus species Felis concolorGenus is capitalized; species is NOT.If you can’t italicize, underline the genus and species!
8Classification TodaySpecies with similar evolutionary histories are classified more closely together.-when organisms share a common ancestor, they share an evolutionary history
9Levels of Classification -based on contributions of both Aristotle and LinnaeusThere are 7 levels of classification.Remember the first letter of this sentence:King Philip Came Over For Good Spaghetti.
107 Levels of Classification Kingdom broadest levelPhylumClassOrderFamilyGenusSpecies most specific
12Taxonomic Categories Taxon- a named group of organisms Taxa range from having broad diagnostic characteristic to having specific characteristicsGenus- is defined as a group of species that are closely related and share a common ancestor
13Taxonomic CategoriesFamily- is the next higher taxon, consisting of similar, related genera.Ursidae family contains 9 species of bears
14Higher Taxa Order- contains related families Class- contains related ordersBears belong to order carnivora and class mammalia
15Higher Taxa Phylum or division- contains related classes Kingdom- contains related phlya or divisionsDomain is the broadest of all taxa and contains one or more kingdomsBears are classified in phylum chordata, Kingom Animalia, and Domain Eukarya
17Using the Classification System Field guides help identify organisms.-they highlight differences between similar organisms (like trees)Taxonomic Key (AKA Dichotomous Key)-paired statements that describe the physical characteristics of different organisms
18Taxonomic Key1. Fruits occur singly Go to 31' Fruits occur in clusters of two or more Go to 22. Fruits are round Grapes2' Fruits are elongate Bananas3. Thick skin that separates easily from flesh Oranges3' Thin skin that adheres to flesh Go to 44. More than one seed per fruit Apples4' One seed per fruit Go to 55. Skin covered with velvety hairs Peaches5' Skin smooth, without hairs Plums
19Domains Broadest, most inclusive taxon Three domains Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles)Eukarya are more complex and have a nucleus and membrane-bound organelles
20Sewage treatment plants, thermal vents, etc. Archaea live in harsh environments and may represent the first cells to have evolved.Sewage treatment plants, thermal vents, etc.
21Many bacteria are important environmentally and commercially. Eubacteria, some of which cause human diseases, are present in almost all habitats on earth.Live in the intestines of animalsMany bacteria are important environmentally and commercially.
22Domain Eukarya is Divided into Kingdoms Protista (protozoans, algae…)Fungi (mushrooms, yeasts …)Plantae (multicellular plants)Animalia (multicellular animals)
23Protista Most are unicellular Some are multicellular Some are autotrophic, while others are heterotrophic
24Fungi Multicellular, except yeast Absorptive heterotrophs (digest food outside their body & then absorb it)Cell walls made of chitin
25Plantae Multicellular Autotrophic Absorb sunlight to make glucose – PhotosynthesisCell walls made of celluloseGrowth, with increases in size and number of cells, is part of development.Development involves many stages from conception until death.
26Animalia Multicellular Ingestive heterotrophs (consume food & digest it inside their bodies)Feed on plants or animals
29Similarities and Differences in the Protist Kingdom All are eukaryotes (cells with nuclei).Live in moist surroundings.Unicellular or multicellular.Autotrophs, heterotrophs, or both.Some can move - others cannot.
303 categories of Protists: Animal-likeFungus-likePlant-like
31Animal-like Protists (Protozoans) *Unicellular Heterotrophs*Four groups based on movement: those with flagella, cilia, pseudopods, and the ‘others’.
32Protozoans with Pseudopods Pseudopods also called ‘false feet’Cell membrane pushes in one direction & the cytoplasm flows into the bulge.This allows the protozoan to move, dragging the rest of the cell behind it.
33EXAMPLE OF HOW PSEUDOPODS MOVE Pseudopod MovementEXAMPLE OF HOW PSEUDOPODS MOVEFLOWPUSHDRAG
34Pseudopods & FeedingThey can form pseudopods to surround & trap food. Then form a food vacuole to break down food in the cytoplasm.
35Pseudopods Reproduce by mitosis Contractile vacuole - it collects extra H2O & expels it from cellThin cell membraneNo definite shape.Example - Amoeba
36Protozoans with ciliaCilia - hairlike structures - help organisms move, get food and sense environment.Multicellular with 2 nuclei.1 nuclei controls everyday functions1 nuclei is for reproduction.Reproduce by mitosis orconjugation.
37CiliatesOral groove lined with cilia - moves H20 containing food into food vacuole at end of oral groove.Food vacuole breaks down food and sends through cell.Anal pore sends out waste.Example of protozoan w/ cilia: paramecium.
39Protozoans with flagella Organisms called zooflagellatesUse long whiplike part called flagella to move.These usually live inside other organisms.
40Other Protozoans Called sporozoans - parasites Feed on cells & body fluids of hostsSporozoans like Plasmodium (causes malaria) have more than 1 host: mosquitoes and then humans
41Examples of Animal-like Protista Cilates- move by ciliaSarcodines- pseudopodsSporozoans- sporesZooflagellate- Flagella
42Plantlike Protists Better known as algae Autotrophs Size: unicellular to very largeContain different pigments so they come in different colors.Euglena: special type of algae -when there is no sunlight they become heterotrophic.
43Plant-like protists are algae. Algae are eukaryotic autotrophs.They, along with other eukaryotic autotrophs, form the foundation of Earth’s food chains.They produce much of Earth’s oxygen.
44There are three unicellular phyla of algae: Phylum EuglenophytaPhylum BacillariophytaPhylum Dinoflagellata
45Members of first phylum of algae, Euglenophyta, are both plant-like and animal-like. Euglena are autotrophs since they make food from sunlight andHeterotrophs since they ingest food from surrounding water.
47The second unicellular algae, Bacillariophyta, are photosynthetic autotrophs. They have shells of silica.They make up a large portion of the world’s phytoplankton which is Earth’s largest provider of oxygen.
49The third unicellular algae, Dinoflagellata, are a major component of marine phytoplankton. These algae have at least two flagella set at right angles to each other and thick cell walls made of cellulose plates.Blooms of dinoflagellates cause “Red Tide.”
55Rhodophyta are red seaweeds. They are found in warm or cold marine environments along coast lines in deeper water.They absorb green, violet, and blue light waves. These light waves are able to penetrate below 100 meters.
59The last of the multicellular algae are the green algae from the Phylum chlorophyta. Most green algae are found in fresh water habitats.
60A Volvox is a hollow boll composed of hundreds of flagellated cells in a single layer.
61Chlamydomonas are actually unicellular and flagellated.
62Funguslike Protists Like animals, they are heterotrophs Like plants, they have cell wallsReproduce by spores (tiny cells that can grow into a new organism)Not in fungi kingdom because they can move at one point in their lives.Example are water or slime molds.
63Fungus-like protists, Myxomycota and Oomycota are decomposers. Phylum Myxomycota are made up of plasmodial slime molds.Phylum Oomycota is made up of water molds and downy molds.