BIOL150 Lecture 5 2024 Taxonomy and Cells PDF

Taxonomy and Cells BIOL 150 Lecture 5  Taxonomy: Life’s filing system Approximately 2.0 million...

Taxonomy and Cells BIOL 150 Lecture 5  Taxonomy: Life’s filing system Approximately 2.0 million species named 2-100 million species still to be discovered https://charge.wisc.edu/botany/images/Tree_of_life_1000w.png Taxonomy How do we organize living things on our planet? Taxonomy: the science of classification Group organisms together by common elements/relationships  History of Taxonomy Aristotle (300s BC) First classified living things into plants and animals Aristotle’s Ladder of Nature http://media1.shmoop.com/images/biology/biobook_taxonomy_graphik_5.png https://covers.openlibrary.org/b/id/7171760-L.jpg  History of Taxonomy Carolus Linnaeus - the “Father of Taxonomy” (1700s) Linnaeus hierarchical system: 2 Kingdoms of living things: Plants and Animals Plants included every living thing that did not move or eat and that continued to grow throughout life. Animals included every living thing that moved, ate and grew to a certain size. Each kingdom was divided into classes NOTE: Phylum category came post-Linnaeus http://media1.shmoop.com/images/biology/biobook_taxonomy_graphik_6.png Linnaeus’s Binomial Nomenclature Binomial Nomenclature Two Naming  Linnaeus’s Binomial Nomenclature Involves organizing an organism’s scientific name into a combination of two terms Genus name and the species Species: a group of organisms that have similar traits and are able to produce fertile offspring Genus: a group of similar species Both terms are italicized and the Genus is also capitalized. Example: humans are classified as Homo sapiens genus = Homo species = sapiens http://media1.shmoop.com/images/biology/biobook_taxonomy_graphik_6.png Other examples include: Escherichia coli Mus musculus Ceratotherium simum Dama dama Leo panthera Giraffa camelopardalis  Classifying Cells! Rewind to 1674… Antonie van Leeuwenhoek (pronounced Lee-von-hook) first observed microscopic single celled organisms At first, these organisms were simply classified into either the plant or animal kingdom By 1866, a third kingdom of life was proposed - Kingdom Protista. The protists included all single-celled organisms https://micro.magnet.fsu.edu/primer/museum/images/leeuwenhoek.jpg https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSwda3Ws-KK4ouEoZCYG9u9HqhVgcBdliSAQYyMwOSyOAAFSd78  Classifying Cells Further… As microscopes became more powerful, scientists began to notice a striking difference amongst these single celled organisms. Organisms without nuclei were called prokaryotes. Organisms with nuclei were called eukaryotes. Pro = before Eu = well, good, true Karyon = nut/kernal (nucleus) https://en.wikipedia.org/wiki/Cell_nucleus#/media/File:Blausen_0212_CellNucleus.png Classifying Cells Further… 1938: Kingdom Protista split further into Kingdom Monera (prokaryotes) and Kingdom Protista (eukaryotes) 1960s: a rank above Kingdom, Domain, was created. Life was now split into 2 domains, Prokaryota and Eukaryota Domain Prokaryota Domain Eukaryota Kingdom Protists Kingdom Monera Kingdom Plants Kingdom Animals  In 1969, yet another Kingdom was added to the Eukaryote Domain. Recognizing that fungi weren’t really plants, but weren’t really animals either, Kingdom Fungi was added.  Addition of Fungi was due to nutritional requirements! Animals are heterotrophs (feed on others) Fungi are mostly saprotrophs Plants are mostly (break down dead matter) autotrophs (self-feeding)  How organisms were classified… Historically, classification was based on appearance or ability. For example: if creatures had wings and flew, they would be classed together. Analogous traits: features that are used to do the same function Wings in pterosaurs, bats and birds but evolved separately are analogous traits: they look the (wings on butterflies, same but evolved separately. bats and birds) http://www.talkorigins.org/faqs/precursors/images/homology.jpg  How organisms were classified… With more study and discoveries, it became more appropriate to classify based on underlying structural similarities. Homologous traits: traits with similar internal structure (human arm, bat wing) due to sharing a common ancestor http://calaski.wordpress.com/science-units/biological-evolution-unit/evidence-for-evolution/homologous-structures/ Classification continues to evolve… DNA discovery led to further classification Prokaryotes were divided into Eubacteria and Archaebacteria. These arguments were accepted, and the three domains, six kingdom system was agreed upon.  Three Domains Six Kingdoms BACTERIA EUBACTERIA ARCHAEA ARCHAEABACTERIA LIFE PROTISTA EUKARYA PLANTAE FUNGI ANIMALIA  Modern Linnaeus Taxonomy Hierarchical system: Kingdom➔ Phylum➔ Class➔ Order➔ Family➔ Genus➔ Species Mnemonic Device: King Philip Came Over From Germany to Spain http://www.scienceprofonline.com/biology-general/what-are-biological-systematics-taxonomy-phylogeny.html  Example: Classifying Humans Go upwards to become more classified http://vignette3.wikia.nocookie.net/community-sitcom/images/e/ed/Taxonomy_chart.jpg/revision/latest?cb=20141211181450  Example: Classifying Brown Bears Eurasian brown bear https://www.cinchlearning.com/clarity/cinch/glencoe_science_2012_texas/images/ebooks/uploads/undefined/clr1311342712_5441.jpg Phylogeny Phylogeny: the connection in evolutionary biology between all groups of organisms as understood by ancestor/descendant relationships Many groups of organisms are now extinct, and without their fossils we would not have as clear a picture of how modern life is interrelated. Phylogenetic trees/cladograms: diagram that shows the relationships among groups of organisms (like genealogies of species)  Phylogenetic Tree/Cladogram https://www.cinchlearning.com/clarity/cinch/glencoe_science_2012_texas/images/ebooks/sci7/201_2/sci_201_2_figure10.jpg Phylogenetic Classification The Importance of Classification to Technology, Society and the Environment Understanding the evolutionary relationships among species and groups of organisms can have important consequences in the medical field, in agriculture and in the conservation of biodiversity For example… When scientists are looking for sources of pharmaceutical drugs, hormones and other important medical products, they can narrow their search to species closely related to organisms already known to provide valuable proteins or chemicals  Understanding phylogeny can help scientist trace the transmission of disease and develop and test possible treatments. Disease can spread more rapidly between species that share certain genetic characteristics Creutfeldt-Jakob disease can spread from cows to people  In agriculture, ways to increase crop yield and disease resistance have already been developed by cross- breeding closely related species Biological control through use of natural predators, parasites and disease depends on knowledge of different taxa and their characteristics Summary Modern classification organizes diversity according to evolutionary relationships Taxonomists rely on morphological, physiological and DNA evidence to identify and classify species Anatomical evidence includes comparing the structure and form of organisms, including bones Summary… Physiological evidence includes comparing the biochemistry of organisms including proteins, DNA sequence Into to Cell Biology (Finally!!)  What is a cell? The term “cell” was coined by Robert Hooke (1665) Cork under microscope was made up of structures that reminded him of cells in a monastery Believed that cells only existed in plants and fungi http://askabiologist.asu.edu/content/robert-hooke What is a cell? CELL: structural and functional unit of ALL living organisms The average adult human is made up of approximately 100 trillion cells 210 distinct cell types  Cell Structure and Function Cells come in a variety of shapes and sizes. Cell Structure is closely related to function. http://mandevillehigh.stpsb.org/teachersites/laura_decker/cell_structure_and_function_notes.htm Cell Size Varies Based on Type Human cells range in size and shape from a few micrometers (red blood cells) up to 4 feet in length (some nerve cells). Example approximately 250 red blood cells (each cell is 8 µm in diameter) could fit on the head of a pin  Cell Structure Example: Red Blood Cell (RBCs) flexible, donut- shaped cells that can easily maneuver through tiny veins and capillaries https://www.reference.com/health/happens-many-red-blood-cells-891c9a08c6bfe4aa  Cell Structure Example: Nerve Cell cells are spiky and may have long tails to allow them to carry electrical messages to distant body parts http://www.clipartbest.com/cliparts/9cz/xzd/9czxzdbcE.jpeg https://static.independent.co.uk/s3fs-public/thumbnails/image/2014/11/24/17/17-NerveCells-Rex.jpg  Antonie van Leeuwenhoek First person to observe a live cell (1674) used a simple, handmade microscope to observe pond scum & discovered single-celled organisms– the algae Spirogyra. termed them “animalcules” observed blood cells from fish, birds, frogs, dogs, and humans Leeuwenhoek’s animalcules These observations eventually led to the development of the cell theory. http://fineartamerica.com/featured/drawings-of-animalcules-form-leeuwenhoeks-letter-dr-jeremy-byrgess.html 150-200 Year Gap in Cell Discoveries Between the Hooke/Leuwenhoek discoveries (~1660-70s) and the mid 19th century, very little cell advancements were made. Spontaneous generation Hypothetical process by which living organisms evolve from nonliving matter Archaic theory that used this process to explain the origin of life. Many believed in spontaneous procreation because it explained such occurrences as the appearance of maggots on rotting meat or fleas in dust Development of Cell Theory 1838 1839 1858 Matthias Schleiden Theodor Schwann Rudolf Virchow German Botanist German German Physician Physiologist All plant parts are All animal Cells must arise made of cells. tissues are from preexisting composed of cells. cells Original Cell Theory 3 Components: 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of life in all living things. 3. All cells are produced by the division of preexisting cells.  Modern Cell Theory Added 4 more part to original cell theory: 4. Hereditary information (DNA) is passed on from cell to cell during cell division. http://dl.clackamas.edu/ch106-10/images/celldiv1.gif  Modern Cell Theory 5. All cells are basically the same in chemical composition. Carbs, lipids, proteins, nucleic acids 6. All basic chemical & physiological functions are carried out inside the cells (metabolism and biochemistry). Example: Cell respiration in mitochondria http://hyperphysics.phy-astr.gsu.edu/hbase/biology/imgbio/eltranmit.gif Next Up Prokaryotes vs Eukarotyes Anatomy of Cells