Module 3 Bio 121.pdf

Diversity of life Edward Osborne Wilson ----> biological diversity or biodiversity a measure of the variety of life first to use the term “biodiversity” in a paper (1988) Biodiversity is often described on three levels: 1) __________ diversity describes the variety of habitats present 2) species dive...

Diversity of life Edward Osborne Wilson ----> biological diversity or biodiversity a measure of the variety of life first to use the term “biodiversity” in a paper (1988) Biodiversity is often described on three levels: 1) __________ diversity describes the variety of habitats present 2) species diversity is a measure of the number of species and the number of individuals of each species present 3) ________ diversity refers to the total amount of genetic variability present Classification & Hierarchy of Life Scientific study of the kinds & diversity of organisms and the relationships among them = discipline of ______________ 3 sub-disciplines Taxonomy Nomenclature Greek words: Latin words: nomen taxis = arrangement nomen = name nomos = law calare = to call theory & practice of classifying organisms into taxa within a hierarchy Phylogenetics study of the evolutionary history or relationships of organisms process where scientific names are produced for taxa at all hierarchal levels to provide a common ground in which biologists can communicate about specific taxa Classification of Life 1st attempt to classify living organisms came from: ______________(384-322 B.C.) Greek - organisms diverse, some more complex than others - one of the first to classify the relationships of living things in a hierarchical ladder of life = scala naturae (“scale of nature”) - [ladder] based on the complexity of structure and function so that higher organisms showed greater vitality and ability to move - divided living organisms into plants & animals based based on whether they had the ability to move or not - further classified animals based on their modes of transportation (air, land, water) scala naturae (“scale of nature”) French version man monkey plants birds fishes serpents metals sulphur insects air Non-biological substances Carolus Linneaus (18th Century) - swedish botanist - passion for classification (classified everything) Taxonomic hierarchy Classification Scheme of Linneaus 7 levels (each a subdivision of the rank above) Imperium ("Empire") Regnum ("Kingdom") Classis ("Class") Ordo ("Order") Genus Species Varietas ("Variety") - a species variant Changes to the Classification Scheme of Linneaus Phylum Family Imperium ("Empire") Regnum ("Kingdom") Classis ("Class") Ordo ("Order") Genus Species Varietas ("Variety") - a species variant Modern classification scheme Kingdom Phylum Class Ordey Familt Genus Species Modern classification Scheme (taxonomic hierarchy): Each level has some characteristics in common - based on morphological, physiological and/or genetic traits Animalia Kingdom Chordata Phylum Class major taxonomic ranks or levels Mammalia Order Rodentia Family Genus Species Sciuridae Urocitellus Urocitellus richardsonii Class Mammalia (3 traits): _____________ - insulation, aid in sensory touch, etc. __________________ - modified sweat glands ---> milk 3 ear bones - transmission of vibrations from the tympanic membrane (eardrum) to the inner ear Order Rodentia (1 trait): dentition highly specialized for gnawing The number of kingdoms has varied Carolus Linneaus [Swedish] 1735 Ernst Haeckel [German Biologist] 1865 2 Kingdoms Vegetabilia (plants) Animalia unicellular organisms 3 Kingdoms Protista Plantae Animalia fungi = for all unicellular organisms Edouard Chatton [French] 1925 ------> prokaryotes & eukaryotes Herbert Copeland [American Biologist] 1956 Robert Whittaker [American] 1969 4 Kingdoms Monera Protista Plantae Animalia prokaryotes eukaryotes 5 Kingdoms Monera Protista Plantae Fungi Animalia prokaryotes eukaryotes 5 Kingdoms 1969 Carl Woese (1970’s) Separation of Monera (prokaryotes) into Eubacteria & ___________________ based on analyses of DNA sequence data addition of a new taxonomic rank = Domain Kingdom Carl Woese (1970’s) 3 Domains BACTERIA ARCHAEA Eubacteria Archaebacteria 9,280 spp. Prokaryotes EUKARYA membrane-bound nucleus 1,7925,200 spp. lack a membrane-bound nucleus Eu (Gk) = true Archaea derived from arkhaios (GK) = ancient [archaic] Representative organisms Domains Kingdoms Eubacteria Archaea Fungi Protista Plantae E u k a r y a Animalia lack a membrane-bound nucleus Prokaryotes formerly Monera BACTERIA circular chromosome peptidoglycans in cell wall membrane lipids ARCHAEA yes EUKARYA yes present absent ester-linked unbranched ether-linked branched peptidoglycans = composed of carbohydrates cross-linked by peptides (2 or more amino acids linked in chain) more resistant to extreme temperatures Bacteria and Archaea are as different from each other as they are from Eukaryotes. Eukaryotes share a more recent common ancestor with the Archaea than with Bacteria. Prokaryotes Eukaryotes BACTERIA ARCHAEA EUKARYA common ancestor ancestors Image from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings very ancient prokaryotes Systematics Nomenclature 25 representative organisms Latin words: nomen = name calare = to call = process where scientific names are produced for taxa at all hierarchal levels to provide a common ground in which biologists can communicate about specific taxa What is its name ? ____________ ___________ flickertail marmot common names Urocitellus richardsonii scientific name named after the naturalist, Dr. John Richardson Latin: uro = “ tail” & citellus = “ground squirrel” This system of naming organisms ( = binomial nomenclature) was constructed by Carolus Linneaus in 1753 Image: Wikipedia Carolus Linneaus 1753 - system of binomial nomenclature How many species names did he create ? 7,700 species of plants 1753 4,400 species of animals 1758 Binomial nomenclature system Rules: - each type of organism has only one name - no two kinds of organisms bear the same name two parts of the name (Binomen): (i) Generic or genus name (ii) Specific epithet (“trivial name”) Urocitellus richardsonii Scientific name ______________ are in Latin Genus name begins with a capital written in italics or underlined the first letter of the specific epithet is in lower case Urocitellus richardsonii scientific name named after the naturalist, Dr. John Richardson Latin: uro = “ tail” & citellus = “ground squirrel” Changes in scientific names Arctomys richardsonii Sabine, 1822 Authority and year Urocitellus Obolenskij, 1927 Brackets to indicate change Authority Urocitellus richardsonii (Sabine, 1822) 1. Originally described by Sabine in 1822 as Arctomys richardsonii. 2. In 2009, Helgen et al (2009) transferred Arctomys richardsonii to the genus Urocitellus. The genus Urocitellus was created by Obolenskij in 1927. Scientific names may change but the species authority & genus authority do not Image: https://en.wikipedia.org/wiki/Richardson%27s_ground_squirrelImage: Scientific name Urocitellus richardsonii (Sabine, 1822) Brackets = name change Species authority person(s) who were the first to describe this as a new species Another rule of nomenclature: Cannot name a species using your own name Castor Linnaeus, 1758 Castor canadensis Kuhl, 1820 Castor fiber Linnaeus, 1758 Images: Wikipedia Anas L. Anas Linnaeus, 1758 Anas platyrhynchos Linnaeus, 1758 In 1758, Linnaeus described the Canada goose using the species name: Anas canadensis Synonym (a name that is no longer valid) Images: Wikipedia Branta Scopoli, 1769 Branta canadensis (Linnaeus, 1758) 3 types of extant mammals (class Mammalia) Placenta(complex) Live birth Mammary glands (lactation) lay eggs (no live birth) Images: https://en.wikipedia.org/: What happens if the same animal is described twice ? Binomial Classification rules: “no two kinds of organisms bear the same name” e.g., The Law of Priority (Article 25) says that if a genus or species has been accidentally given two names, only the earlier one is valid. The later name becomes a junior “junior synonym” Duck-billed platypus described by George Shaw in 1799 named it as Platypus anatinus - discovered the genus name belonged to the wood-boring beetle (Platypus) independently described by Johann Blumenbach in 1800 as Ornithorhynchus paradoxus Ornithorhynchus anatinus (Shaw, 1799) Platypus anatinus Shaw, 1799 Ornithorhynchus paradoxus Blumenbach, 1800 Ornithorhynchus Blumenbach, 1800 _______________ = single specimen designated as the namebearing type of a species when it was established [by original author] The specimen to which all others are compared. There is a holotype for each species. Allotype = a specimen of the opposite sex to the holotype. Paratypes = specimens of the type series other than the holotype. Type specimens must be preserved permanently and may not be living plants or cultures. Cultures of fungi and algae, if preserved in a metabolically inactive state, are acceptable as types. Role of Natural History Museums the richest source of collections in the world ----> Paris, London & Washington 1. French National Museum of Natural History [Paris] 2. British Museum of Natural History [London] foundation of collection 1756 [new museum in 1881] 70 million specimens many of historical & scientific value [specimens collected by Darwin] formally founded 10 June 1793 (during the French Revolution) one of its foundation professors Jean-Baptiste Lamarck over 60 million specimens 3. Smithsonian National Museum of Natural History [Washington] established in 1910 125 million specimens Images: Wikipedia Role of Natural History Museums -------> "catalogues of ______" acquire, conserve, restore, manage & exhibit very important collections of natural history, living organisms, inert collections and databases specialising in taxonomy, identification and conservation understanding diversity and its origin What are__________” ? Latin word = "kinds" or "appearance" Organisms classified based on their appearance (observable phenotypes) = the Morphological species concept Morphology = outward appearance (shape, structure, colour, pattern) and the form and structure of the internal parts (e.g. bones and organs) identify / distinguish species using morphological features --------------> Morphological species concept Is there a problem with this species concept ? some species morphological morphological variation (i.e. diversity) How do we know if they are different species or the same species ? Theodosius Dobzhansky, 1920’s (American geneticist) proposed that: each species is _____________________ from other species Biological species concept (Ernst Mayr, 1942) evolutionary biologist expanded ideas of Dobzhansky : - “Species are groups of natural populations whose individuals which are ___________________ from other such groups.” - interbreeding (sharing a common gene pool) & produce fertile offspring limitations not applicable to: 1. ______________________ 2. _______________________ Morphological species concept Images: http://microbeonline.com/colony-morphologybacteria-describe-bacterial-colonies/ AND http://textbookofbacteriology.net/growth_2.html _____________ species concept - Species are defined in terms of their ecological niches, focussing on unique adaptations to particular roles in a biological community Bacteria: same species are likely to use same types of resources (sugars, vitamins) & grow under the same types of conditions (temperature, pH, etc.) Biological species concept (Ernst Mayr, 1942) “A species is a group of actually or potentially interbreeding natural populations whose individuals are reproductively isolated from other such groups.” gen B w e flo A E flow e gen Species 1 share same gene pool What are these barriers? C reproductively isolated (there is one or more barriers to gene flow ) interbreeding = sharing a common gene pool Must produce viable offspring (not _____________) D Species 2 F Biological species concept What types of barriers prevent reproduction ? (i.e. prevent interbreeding between species) ? I. ___zygotic reproductive barriers prevent mating or fertilization II. ____zygotic reproductive barriers prevent development of ____________adults I. Prezygotic reproductive barriers 1) _____________________________ garter snakes northwestern garter snake Thamnophis ordinoides moist meadows, open grassy patches Several spp. in Nth. America some in water, others on land ribbon snakes Thamnophis proximus shallow water, aquatic vegetation on banks Frogs: Bufo americanus and B. woodhousei can interbreed and produce viable offspring but they almost never do in nature Bufo americanus breeds in shallow rain pools Bufo woodhousei breeds in the quiet waters of streams little chance of hybrid offspringbeing produced 2) ______________ isolation: Species have different mating or flowering seasons or times of the day, or become sexually mature at different times of year. field crickets morphologically similar do not differ in song use same habitats Gryllus veletis matures in spring Gryllus pennsylanicus matures in fall reduces encounters for interbreeding Image from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings Images from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings Eastern Spotted Skunk (Spilogale putorius) - mating occurs in March & April (July & August: in southern parts of range) Western Spotted Skunk (Spilogale gracilis) - mating occurs in September Spotted Skunks - morphologically similar (previously thought to be same species) - distributions overlap - but breed in different seasons -------> no _________________matings 3) _______________ isolation: There is little or no sexual attraction Series of simple whistles (4-5 notes) Longer flutelike gurgling notes that go down in scale between males and females of different species due to differences in behaviour. morphologically similar similar colouration use same types of habitat ranges overlap in central U.S. Very little interbreeding - use different songs to attract mates allopatric populations (no overlap) the two species are sympatric [zone of sympatry] Image from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings Behavioural isolation (cont.): Includes high-step action by ¢ ---> show off blue-feet to ™ blue-footed boobies (Sula nebouxii) red-footed boobies (Sula sula) Image sources unknown spectrograms Behavioural isolation (cont.): Darwin’s finches (Galápagos Is.) have (differences in frequency & rate ) Unique songs, attract only conspecifics hello Images from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings 4) ______________ isolation Structural differences in genitalia or flowers prevent copulation or pollen transfer between two different species. Many plant species have flower structures that are adapted to ____________ pollinators Example: sympatric monkey flowers Mimulus cardinalis flowers are visited by hummingbirds Mimulus lewisii flowers are visited by bumbleees Images from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings 5) ________________ Male and female gametes die before uniting or fail to unite Example: red & purple sea urchins Strongylocentrotus purpuratus Strongylocentrotus franciscanus Sperm & eggs released into surrounding water where they fuse & form zygotes. Gametes of red & purple sea urchins are unable to fuse. Image from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings 2. Postzygotic reproductive barriers i) __________________ Hybrid zygotes fail to develop or to reach sexual maturity. Example: salamanders - some salamander subspecies of genus Ensatina live in same regions where they occasionally hybridize - but most hybrids do not develop (those that do are frail) Images from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings i) Hybrid inviability (another example) sheep (Ovis aries) 54 chromosomes x goat (Capra aegagrus) 60 chromosomes Hybrid embryo’s die ii) Hybrid ___________ Hybrids fail to produce functional gametes x ¢ donkey (Equus asinus) ( 62 chromosomes) ™ horse (Equus caballus) ( 64 chromosomes) Mule (63 chromosomes) [sterile] Images from Biology 7th Edition, by Campbell and Reece. 2005. Pearson-Benjamin Cummings ™ donkey x ¢ horse “hinny” [sterile] iii) Hybrid ________________: Offspring of hybrids are weak or infertile. species 1 (“parent” A) X species 2 (“parent” B) ------> F1 hybrid (viable & fertile) F1 hybrid X F1 hybrid (viable & fertile) (viable & fertile) offspring (F2) are F1 hybrid X (viable & fertile) either parent species Example: strains of cultivated rice feeble or sterile Summary Two types of barriers prevent interbreeding between different species I. Prezygotic reproductive barriers prevent mating or fertilization 1) 2) 3) 4) 5) habitat isolation temporal isolation behavioural isolation mechanical (anatomical) isolation gamete isolation II. Postzygotic reproductive barriers prevent development of fertile adults 1) 2) 3) hybrid inviability hybrid sterility hybrid breakdown may be a combination of several barriers