Taxonomy Grouping Organisms
What is Taxonomy? • Taxonomy is the branch of biology that groups and names organisms based on studies of their different characteristics. • A group of organisms is called a taxon (plural, taxa). • The tool biologists use to accomplish this is classification. • Taxonomy can change
Biological Classification Systems • Aristotle (384-322 B.C.) • Classified all organisms into two groups: plants and animals. • Using physical differences he further classified them into smaller groups.
Why is standardization important? • Makes it easier to identify. • Makes it easier to understand biological diversity. • Worldwide recognition. • Useful for scientists working in agriculture, forestry, and medicine. • Beneficial for the economy.
Breaking It Down • Taxonomic ranking ranges from very broad characteristics to very specific ones. • Taxa from largest to smallest: • Domain,AND THEN: *Order * Kingdom, *Family *Phylum (similar classes), *Genus *Class (similar orders), *Species (Remember: King Phillip Came Over for Good Soup)
From Domain to Species • Domain – Eukarya (broadest category). • Kingdom – Animalia • Phylum – Chordata (spinal cord). • Class – Mammalia (mammal). • Order – Carnivora • Family – Felidae • Genus – Lynx • Species – Lynx rufus (Bobcat), Lynx canadensis (Lynx).
Six Biological Kingdoms
Kingdoms • The six kingdoms are determined by similarities such as: structure, behavior, DNA, location . • From the most simplistic organisms to the most complex, the six kingdoms are: • Eubacteria (prokaryotes), • Archaebacteria (prokaryotes), • Protists (eukaryote), • Fungi, • Plants, • Animals.
Phylogeny • Phylogenic classification uses evolutionary history to classify organisms. • Species that share a common ancestor also share an evolutionary history. • Reveals evolutionary relationships. • Cladistics is a biological classification system that is based on phylogeny. • A cladogram is a model showing evolutionary history.
Cladogram
Dichotomous Key • A tool that helps to classify organisms by narrowing down choices eventually leading to the correct answer.
Six Divisions of Life
Viruses • Non-living • Parasitic • Simple structure – Protein coat, capsid, genetic material, & tails. • Replication Cycles: Lytic & Lysogenic Cycle • Viruses that affect humans – HIV (destroys T- cell helpers), Herpes, Flu,Chicken Pox, & Shingles.
Eubacteria & Archaebacteria • Prokaryotes • Biochemical differences • Structural differences • Arose from a common ancestor several billion years ago.
Similarities & Differences Archaebacteria Eubacteria Heterotrophs Live almost everywhere Autotrophs – Chemosynthetic & Photosynthetic (Cyanobacteria). Asexual reproduction – binary fission. Sexual reproduction – conjugation. Adaptations • Anaerobic • Extremists • 3 Types: • Live in marshes, lake sediments, & digestive tract of mammals – produce methane. • Live in extremely salty water like the Great Salt Lake in Utah. • Hot, acidic water of sulfur springs & hydrothermal vents. • Only asexual reproduction.
Bacteria Beneficial Harmful Bacteria cause disease in plants & animals. Can enter through openings in the skin, mouth, or nose. Can be carried in food, water, or air. Can interfere with normal bodily functions. Releases toxins that attack the host. Turn to page 498. Superbugs Defy Drugs. • Help to fertilize fields – nitrogen fixation. • Recycle nutrients on Earth - decomposers . • Produce foods – cheese & yogurt. • Aids in digestion – providing vitamins & enzymes. • Produce antibiotics that destroy other types of bacteria.
Protists • The most diverse organisms of all kingdoms. • Unicellular or multicellular. • Are all Eukaryotes • Heterotrophic or autotrophic • Reproduce sexually, asexually, or through spores depending on the type. • Cause diseases – malaria & sleeping sickness.
Heterotrophic Protists • Animal-like (heterotrophic) protists are called protozoans. • Grouped according to the way they move or grouped together because they are parasites. • Four main groups: Amoebas, Flagellates, Ciliates, & Sporazoans. • Amoebas – live in water, some are an important part of marine plankton. • Flagellates – Parasites that cause disease (sleeping sickness). Beneficial to termites. • Ciliates – paramecium, reproduces by conjugation. • Sporazoans – Produce by spores, all are parasites, inernal parasite, lives off of host in areas that has a nearby food supply. Ex –malaria.
Autotrophic Protists • Plantlike (autotrophs) Ex. – algae. Diatoms – phytoplankton. Lack roots, stems, or leaves. • Autotrophs produce much of the oxygen in Earth’s atmosphere. • Some are similar to fungi (slime molds, water molds, & downy mildews). Decompose a significant amount of organic material. • Algae are classified into six phyla: euglenoids, diatoms, & dinoflagellates are single cellular. Red, brown, & green are multicellular.
Fungi • Grow best in moist, warm environments. • Most are multicellular. • Basic structural unit is hyphae. • Cell walls made of chitin. • Some cause diseases & are poisonous. • Are decomposers. • Heterotrophs – Extracellular digestion. • Reproduce asexually by fragmentation, budding, or producing spores; sexually when haploid hyphae from compatible mycelia grow together.
Plants • Multicellular eukaryote. • Thick cell walls made of cellulose. • Autotrophs • Photosynthesis - Needs water, sunlight, & carbon dioxide. • Has stems, leaves, & roots. • Sexual reproduction through seeds or spores. • Vascular (most plants. Grasses, & trees) & nonvascular hornworts & liverworts).
Animals • Eukaryotic, multicellular organisms. • Cells have cell membranes, instead of cell walls. • Heterotrophic • Sexual reproduction • Specialized cells that form tissues & organs. • Specialized cells that enable them to sense & seek out food & mates, & allow them to identify & protect themselves from predators. • Symmetry
