Chapter 13 - Systematics

Chapter 13 - Systematics CHAPTER 12 SYSTEMICS: THE SCIENCE OF BIOLOGICAL DIVERSITY 8 pts

Outline TAXONOMY AND HIERARCHIAL CLASSIFICATION

Taxonomy: The science of discovering, describing, naming and classifying organisms Blanketflower, Indian BlanketGaillardia species, hybrids and cultivars

TAXONOMY I. Taxonomy Taxonomy is not static, it is constantly being revised and relearned by each generation APG Classification, 1998 Basal Angiosperms Monocots Eudicots Core Eudicots Caryophylliales Rosids Eurosids I Eurosids II Asterids Euasterids I Euasterids II Englerian System, 1887 Monocotyledonae Dicotyledonae Amentiferae Polypetalae Ranales Centrospermae Gamopetalae Cronquist System, 1988 Magnoliopsida (Dicots) Magnoliidae Hamamelidae Caryophyllidae Dilleniidae Rosidae Asteridae Liliopsida (Monocots)

TAXONOMY I. Taxonomy To a certain extent, we are all taxonomists 1. Edible plants vs medicinal plants vs ornamentals for example 2. Classification can depend on religious or ethnic views, or can be science-based (morphology, DNA sequencing of genes)

PHILOSOPHICAL CONCEPTS II. History of Classification Early classification systems were “artificial classification systems” (did not reflect biological relationships)

Euphorbia (spurge family) Echinocereus (Cactus) Hoodia (Milkweed) All have C3 photosynthesis

HISTORY OF CLASSIFICATION II. History of Classification • The most important of these was De Materia Medica, 1st century AD by Greek physician Dioscorides • Classified 600 medicinal plants designed to improve medical services to the Roman Empire. • Book became the principal book on plant classification for nearly 1,500 years. • Book became the basis for herbals

HISTORY OF CLASSIFICATION II. History of ClassificationHerbals • Herbals: books which document the supposed medicinal properties of plants • 1. Contains: much folklore • 2. Doctrine of signatures (defined): Herbals gave rise to the Doctrine of signatures which holds that if a plant part resembled a part of the human body, it would be useful in treating ailments of that part.

HISTORY OF CLASSIFICATION II. History of Classification Walnut meats which contain something that looks like tiny brains was used to treat brain disease. Hepatica leaves which look like the lobes of liver was used to treat liver ailments

“If a man be anointed with the juice of the herb Rue, the poison of wolf’s bane, mushrooms, or toadstools, the biting of serpents, stinging of scorpions, spiders, bees, hornets and wasps will not hurthim” John Gerard, The Herball, 1597 Ruta graveolens or Rue http://www.desert-tropicals.com /Plants/Rutaceae/Ruta_graveolens.html

The pith of the [Elder] branches when cut in round flat shapes, is dipped in oil, lighted and then put to float in a glass of water; its light on Christmas eve is thought to reveal all the witches and sorcerers in the neighborhood. Richard Folkard, Plant lore, Legends and Lyrics

HISTORY OF CLASSIFICATION 15th century issued in a great era of plant exploration and an expansion of plant classification

Carl Linnaeus 1707 - 1778 Young Swedish Botanist, Zoologist, Physician, and Creationist. Laid the foundation of modern taxonomy creating a hierarchical classification among plants and popularizing the use of binomial nomenclature to name a ‘species’. His Species Plantarum published in 1753 is the starting point for modern nomenclature

HISTORY OF CLASSIFICATION II. History of Classification • Artificial classification system (not based on evolutionary/genetic relatedness) • based primarily on stamen structure and number • Linneaus’ scheme placed cherries and cacti together because they had many stamens per flower. We would classify cacti with cacti and cherries with other fruit trees • significantly simplified the descriptive classification scheme of the day • eg. The Latin description for peppermint was Mentha floribus capitatus, foliis lanceolatis serratis subpetiolatis • or Mentha with flowers in a head, leaves lance shaped, saw toothed with very short petioles

HISTORY OF CLASSIFICATION II. History of Classification 1753, Carolus Linneaus formalized a 2 name system for classification of plants (introduced by earlier botanists), a system still used today Linnaea borealis (twinflower)

HISTORY OF CLASSIFICATION II. History of Classification • Binomial system of nomenclature published 1753 Species Plantarus • Genus and Species: Linnaea borealis L • Language used: Latin • After the binomial name, there is often an abbreviation of the name of the person who did the classification or the authority. L is used for Linnaeus. • If someone has reclassified the plant, the first name will be in parenthesis and a second name will be added

Carl Linnaeus’ Country Home in Hammarby After the devastating fire in 1769 destroyed most of Uppsula except his Garden house, Linnaeus had this stone building (without a heat source) build in 1769 where he kept all his collections of dried plants, insects and stones and held lectures.

Carl Linnaeus’ Country Home Herbarium Cabinet Student benches Linnaeus lecture podium “Studying Horse’

PHILOSOPHICAL CONCEPTS II. History of ClassificationJohn Ray For Linneaus and his successors, the prevailing belief was the recognition of God-given relationships No concept of change and no concept of extinction

Jean-Baptiste Lamarck (1744-1829) formulated new ideas about the relationships between animals, and then about the transmutation of species into new ones. Statue of Lamarck in the Jardin des Plantes, Paris. The inscription reads, "Fondateur de la doctrine de l'évolution" (Originator of the doctrine of evolution)

Lamarck developed two laws to explain evolution: the law of use and disuse, and the law of inheritance of acquired characteristics. The law of Inheritance of acquired characteristics: All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes, or at least to the individuals which produce the young. Lamarck saw spontaneous generation as being ongoing, with the simple organisms thus created being transmuted over time (by his mechanism) becoming more complex and closer to some notional idea of perfection. As organisms became more complex, they were replaced with new simple organisms by the Creator.

By the mid 1800’s most scholars had abandoned the view that species were immutable and had accepted a view of change over time. Darwin The question was how? Darwin’s careful observations provided a natural hypothesis as to how change could occur. Wallace

"Yet in all societies, even those that are most vicious, the tendency to a virtuous attachment is so strong that there is a constant effort towards an increase of population. This constant effort as constantly tends to subject the lower classes of the society to distress and to prevent any great permanent amelioration of their condition". —Malthus T.R. 1798. An essay on the principle of population. Chapter II, p18 in Oxford World's Classics reprint. The Reverend Thomas Robert Malthus 1766-1834 Thomas Malthus: the rate of growth of a biological population will always outpace the rate of growth of the resources in the environment, such as the food supply leaving the poor in distress.

Evolutionary theory (Darwin and Wallace) • 1. There is natural variability within populations and some of that variability is heritable. • 2. Individuals produce more offspring than can survive. • 3. Not all the members of a population will be able to survive and reproduce. Those that do will, on average, be the ones possessing variations—however slight—that make them slightly better adapted to the environment • 4. Populations adapt locally to an environment (can be demonstrated ), become reproductively isolated and finally become new species by gradual accumulation of genetic differences or by abrupt genetic change. Some become extinct.

Acceptance Scientists were the first to accept Darwin’s concepts but since genes were unknown, there was considerable controversy about the mechanism Slowly religious leaders came on board With the discovery of Chromosomes and Mendel’s work (early 1900’s), a deeper understanding of the mechanisms of selection resulted in a “new evolutionary synthesis” that included genetics

Rejection Evolution cannot be correct because it contradicts scriptural teaching Natural selection is not a strong enough to mechanism to function as science says it does If natural selection is selected as an important biological force, there is an obligation to have a perverse view of human nature William Jennings Bryan, 1860-1925 Populist Politician who worked tirelessly for the downtrodden. Detested Darwinism because he feared it “encouraged the exploitation of labor by justifying selfish competition and discouraging reform”

MODERN PLANT CLASSIFICATION

NAMING NEW SPECIES III. Modern Classification New species must be anchored by a “type” Types and other collections are stored in collections called “herbaria” (herbarium) The University of Tennessee herbarium (TENN) is located in Hoskins Library http://tenn.bio.utk.edu/

THEORETICAL FOUNDATION OF NATURAL (BIOLOGICAL) CLASSIFICATION III. Modern Classification • Organisms exhibit differences between individuals and groups. • Some similarities have a genetic/evolutionary basis • Organisms can be given taxonomic rank by their level of similarity • Taxonomic rank reflects real genetic relationships

Thus, all dogs are classified together because they have a common ancestor, the wolf. Only a few genes separate big and small dogs

THE HIERARCHY OF CLASSIFICATION III. Modern Classification • Linnaea borealis • Genus, species

PHYLOGENETICS Outline In biology, phylogenetics is the study of evolutionary relationships among groups of organisms (e.g. species, populations), which is discovered through molecular sequencing data and morphological data matrices. Modern plant classification is being revised to reflect presumed evolutionary relationships based on genetic evidence

Core Eudicots Trees depict evolutionary relationships among vascular plants Papaveraceae (Poppy) Monocots (Grasses, palms) Magnoliales (Magnolia) Austrobaileyales Nymphales (water lily) Amborellaceae Ancestor Gymnosperms Ferns

RELATIONSHIPS ARE PRESENTED AS TREES Present time Species 3 Species 2 Species 1 Species 1 Common ancestor Time (more closely related) Common ancestor (more distantly related)

READING PHYLOGENETIC TREES III. Modern ClassificationPhylogenetic trees Present time Species 3 Species 2 Species 1 Species 1 (AGGTCCGAG) (AAGTCCCGG) (AAGTTCCAG) Common ancestor Time (more closely related) (AGGTCCGAG) (AAGTCCCAG) Common ancestor (AAGTCCGAG)

III. Modern ClassificationPhylogenetic trees Species 1 AGGTCCGAG Species 2 AAGTCCCGG Species 3 AAGTTCCAG Similarity matrix 2 3 1 • Conclusions: • Species 2 and 3 are equidistant from 1 • Species 2 and 3 are most closely related to each other 6/9=.66 1 6/9=.66 2 7/9=.77 3

READING PHYLOGENETIC TREES III. Modern ClassificationPhylogenetic trees Species 3 Species 2 Species 1 Species 1 (AGGTCCGAG) (AAGTCCCGG) (AAGTTCCAG) • Conclusions: • Species 2 and 3 are equidistant from 1 • Species 2 and 3 are most closely related to each other Common ancestor (more closely related) (AGGTCCGAG) (AAGTCCCAG) Common ancestor (AAGTCCGAG)

Outline THE MAJOR GROUPS OF ORGANISMS

THE THREE DOMAINS 0F LIFE Prokarya Prokarya No nucleus No nucleus

CELLS HAVE NUCLEI = EUKARYOTE • EU = TRUE • KARYOTE = HAVING A NUCLEUS Prokaryotes and Eukaryotes

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Chapter 13 - Systematics