Final Exam Study Guide for Principles of Biology II | BIOL 1108, Study notes of Biology

Download Final Exam Study Guide for Principles of Biology II | BIOL 1108 and more Study notes Biology in PDF only on Docsity! Exam 1 11/21/2010
Photosynthetic Organisms  Autotrophs: organisms make own energy (self feeders)  Heterotrophs: get energy from other organisms  Photoautotrophs: autotrophs use light as source of energy  Chemautotrophs: autotrophs that use molecules as source of energy  Chemolithotrophs: oxidize inorganic substances
Origin of life  Abiotic synthesis of small organic molecules, joining of small molecules into macromolecules, transition to membrane bound cells, origin of self-replication molecules
early atmosphere on earth  volcanoes, no free oxygen, bombarded by heat, UV radiation, torrential rains
Hypotheses  Oparin and Haldane: life began from chemical reactions that synthesized organic compounds by reducing inorganic precursors, ocean was prebiotic soup of organic compounds (life arose from here)  Miller and Urey: duplicated organic synthesis under early earth conditions, living cells may have been preceded by aggregates of abiotically membrane-bound produced molecules
Chemical monomers preceded polymers  First genetic code started as RNA, DNA (more stable/accurate later replaced it)
Prokaryotic cells were first life on earth  Stomatolites: layered sedimentary rock provided evidence of early life)
Photosynthetic organisms  Similar to modern cyanobacteria, produce energy through oxidation reactions (thus creating oxygen) Eukaryotes  Unicellular and multicellular, have organelles, complex, membrane-bound, no circular chromosome  Endosymbiosis: facilitated immediate adoption of metabolism  Undergo mitosis  Hypothesis for origin o Cells evolved in which the plasma membrane enfolded to form a nuclear envelope, endosymbionits (prokaryote parasites) entered these cells
Viruses  Cant replicate genes or produce ATP, amino acids, or nucleotides (no independent metabolism)  Most complex form of molecules or simplest form of life
Prions  Infectious protein particles (mad cow disease), can be misfolded or normal)
Prokaryotes (simple, asexual reproduction, no membrane, circular chromosome))  Archaea o No peptidoglycan in cell wall  Bacteria o Positive gram stain=lots of peptidoglycan, negative grain stain=little peptidoglycan
Protists  Protists and eukaryotes evolved from bacteria  Have no alternation of generation  Fungi, animals, and plants evolved from protists  Protozoa: animal-like protists  Mycetozoa: fungus-like protists  Sclerenchyma (simple, support and storage)  Thick secondary wall,, lignified, pits, dead at maturity  Fibers=long/unbranched fibers  Schlerigs=irregular/branched o complex  Xylem  Wood is xylem, ruds axial and radial  Transports water  Tracheary elements  Tracheids o Not perforated at ends, pits, more strong less efficient  Vessel elements o Perforated at ends (perforation plates), more efficient, less strong  Phloem  Food transportation (sugars)  Sieve elements (conducting cells)  Sieve cells (older plants) o Albuminious cells (are their nucleous), not speciliazed at end plate  Sieve tube elements (angiosperms) o Speciliazed at end plate (sieve plates) o Companion cells for nucleus o Pores, connected, form tubes, nacreous (pearly) wall o Primary vascular tissue  Secondary walls resemble annuli or springs which allow the cells to elongate without breaking  Mata elements  Later formed elements  Have a more pitted appearance (stronger but cant elongate)

Plant Tissue  Meristerms o Sites of active cell division (mitosis), embryonic and never mature, plant growth o Large nuclei, small vacuoles, simple, thin wall  Primary meristems o Protoderm: produces different plant cells o Procambium: produces vascular tissue  Apical meristems: shoots and roots, accounts for increase in length (way top), primary growth o (simple, asexual reproduction, no membrane)  Lateral Meristems: increases girth, width, secondary growth o Vascular cambium: angiosperms, thin layer of meristematic cells b/w xylem and phloem  Generates new vascular tissue which leads to secondary growth o Cork cambium: produces bark
Stem Anatomy  Epidermis: outermost layer of cells  Cortex: middle tissue layer  Vascular Bundles: lowest tissue layer (contains xylem and phloem)  Apical bud: way tip of plant  Nodes: where leaves come out  Internode: area between nodes  Axillary bud: bud on point of connection of leave to stem  Megaphylls (evolution) o Enations (non vascularized)microphylls (single)megaphylls (webbed)  Midrib: vein running through middle of leaf  Leaf margin: whole leaf  Petiole: bottom of leaf  Rachis: similar to a stem leading to a leaf branching off of another leaf  Leaflet: pointy part on top of leaf
Root Anatomy (roots are for uptake and storage)  Epidermis: outermost layer of cells, have hair to hold in place/increase surface area (absorption)  Cortex: middle layer, storage, starch grains  Endodermis: surrounds vascular tissue, have suberin (waterproof)  Stele: tissue inside endodermis o Pericycle: divide, give rise to lateral roots o Xylem/phloem o Monocots=pith (star shaped middle), dicots=no pith (circle in middle)  Stem Anatomy o Monocts=vascular bundles randomly arranged, Dicots= pith in a circle  Petal Number o Monocts=fewer petals, dicots=more petals
Leaf duration  Evergreen: lose only some leaves, leaves live long  Deciduous: lose all leaves annually  Abscission: leaves detach via an abscission zone that has a separation/abscission layer where leaf detaches and protective layer where periderm seals off leaves
Uptake and transport  Leafs: take in light and CO2, give off O2 and H20  Roots: take in O2, H20, minerals, give off CO2  Water has to cross at least one membrane before entering xylem in root  Osmosis movement of water through a selectively permeable membrane with diffusion gradient  Water moves from area of high water potential to low water potential, High =+, low=-low=-  Simple diffusion (passive transport): High to low, no proteins or ATP involved  Facilitated diffusion (passive transport): uses a carrier protein, no ATP needed  Active Transport (against diffusion gradient): ATP and transport proteins, pumps push
Water uptake  Water moves from high to low water potential (soilcortexsteele)  Cohesion-tension theory o Water evaporates form leaves, opens stomata, transpiration (giving off water) lowers water potentiol of mesophyll cells, evaporating water film lowers tension of water potentiol, water pulled into cells osmotically from the veins, narrow diameter of conducting elements facilitates strong hydrogen bonding o Water pulled out of soilroot cortexxylemevaporatesdiffuses o Sap rises due to solar power, root has high water potential
Transpiration= Guard cells surround stomata/pore, gas exchange
Phloem transport  Translocation=movement of sugars throughout plant (source to sink) o Source provides organisms, energy, materials o Sinks absorb the organisms, energy, materials o Involves ATP o In a plant sources are the leafs and create sugars and send sugars to the roots (sinks) o Water moves up through the phloem and turgor pressure causes it to go down
Photosynthesis: process where organisms convert light energy to chemical energy which is stored as glucose
Light Reactions  Capture sunlight, store in usable form (photophosphorylation)  Photosystem II= light harvesting, capture an electron and pass it on to photosystem II  Photosystem I=reaction center complexes, produce NADPH (non-cyclic photophosphorylation) o Cyclic photophosphorylation- produces ATP instead  Occurs in chloroplast thylakod membranes that form grana stacks  Chlorophylls A + B dominante, absorb incoming photons and become excited, absorb red and blue, reflect green  Accessory pigments (ex. carotenoids) absorb intermediate wavelengths  Excited chlorophylls=reducing agents, react quickly with oxidizing agent (redox reaction- sunlight only)  Primary job is to generate these high energy molecules Dark energy  Take in CO2, Calvin Cycle takes place, use ATP, NADPH to synthesize sugar  Occur in the stroma of the chloroplast, carbon fixation occurs (fixation of carbon dioxide to something)  Calvin Cycle o Fixation: fixation of carbon dioxide o Reduction: reduction of phosphoglycerate to G3P  CO2 bound to RuBP to help carry the CO2, produces PGA which is reduced to G3P o regenerationL regeneration of RuBP from G3P o one turn requires 1 CO2, 3 ATP, 2 NADPH, G3P needs 3 CO2, glucose needs 6 CO2  RuBp (rubisco) is inefficient, certain plants in tough environments cant use it and evolved into a new beginning part to the system that’s more efficient o Yield 4-Carbon acid instead, called C-4 plants, trap carbon initially to prevent its conversion to phosphoglycerate. Contain enzyme pep carboxylase which binds PEP and CO2 to form the C-4 o Has more CO2, stored at night, used during the day o Have krantz anatomy, radiating wreath like arrangment which helps take in carbon more
o Growth movements (irreversible)  phototropisms: plant moving to light (postivie:toward, negative: away)  auxin produces growth only on one side, asymmetrical growth  nastic movements, doesn’t depend on direction of stimulus  Gravitropism (example of how auxin is used)  Bending of shoot upward/downward, occurs in dark-determined by gravity  Moves statoliths that respond to gravity (amyoplasts)  Roots seeking gravity, auxin distributed to other side to make bend down  Phytochrome o Influences growth and abscission, switches shape o Pr absorbs red light. Pfr absorbs far red light (quick light conversion) o Prpfr =rapid……pfrpr=slow (prolonged dark conversion) o High pfr levels promote flowering in long day plants and inhibit flowering in short day plants o Constans (CO) made when phytochrome activated by light  Stimulates flowering in long day plants, inhibits flowering in short day plants  Thigmotropism o Movement by contact, directional growth in response to touch, plants sensitive to touch o Mimosa: touching induces sudden loss of turgor pressure and will collapse but restore soon  Florigen: singal to flower, eventually found it and named it Flowering Lotus T (FT), same in long day and short day plants  Charles + Francis Darwin o Only blue light causes bending of plants, cut off tip no bending, black foil no bending..etc o Some influence in the shoot apex responding to light, transmitted to stem  Fritt Went o Used agar blocks o Chalondy-went theory=roots being so sensitive to aux results in inhibition on lower side as auxin accumulates
Interphase: stage before mitosis/meiosis  S Phase (synthesis): chromosomes get produced, DNA replication occurs  G2 Phase: interval where chromosome replication is complete but mitosis/meiosis hasn’t begun o Gap between interphase and mitosis  G1 Phase: cells do normal functioning phase, gap between end of mitosis and next interphase
Cytokinesis: immediately follows m phase (mitosis/meiosis), cell plate forms, divides into double amount of cells, 2 daughter cells with a nucleus in each, complete set of organelles
Spindle apparatus: pulls chromosomes to the poles of the cell  Polar microtubules: extend from each spindle and overlap in the middle  Kinetochore microtubules: attach to the chromosomes at the kinetochore (part of centromere=middle)  Centrosome: microtuble organizing center, contain pair of centrioles
Mitosis: results in exact copies of genetic material,no change in chromosome number,yields 2 identical diploid cells  Prophase: chromosomes condense into compact structures called chromatids o marked by formation of spindle apparatus  Pro-metaphase: chromosomes condensed, nucleolus disappears and nuclear envelope disintegrates o Kinetochores form on each chromatid centromere  Metaphase: complete migration to opposite poles of the centrosome o chromosomes lined up in the middle along metaphase plate , like a tug of war occurring  anaphase: centromeres split, under tension, sister chromatins pulled apart o results in two identical new chromosomes  telophase: chromosomes stop moving, makes diploid, 2 independent nuclei form
Meisosis: diplod produces four haploid daughter cells with half the genetic info of the original cell  Differ from mitosis: DNA does not replicate before Meiosis II o chromatids are not identical (crossing over), end products are haploid rather than diploids o genetic diversity  synapsis and crossing over yield genetically different chromosomes  crossing over: chiasmata, occurs in pro-metaphase  synapsis: homologous chromosomes pair along entire length  random chance determines which of the non-homologous chromosomes end up in daughter cells at the end of anaphase I (independent assortment)  meiosis I o starts with tetrads and goes through phases of mitosis o tetrads: double amount of chromosomes o forms 2 diploid daughter cells  meiosis II o cells condense again and go through phases of mitosis o same as mitosis but occurs in 2 cells rather than one and forms 4 haploid cells
Meiotic abnormalities  Non disjunction: failure of homologous chromosomes or siter chromatids to separate o Results in aneuploidy: chromosome lacking or have excess, changes number  GametesMale=sperm or pollen grain…Female=egg  Isogamy=both gametes appear identical  Anisogamy=female gametes are larger  Oogamy=extreme anisogamy, egg is large and sessile (immobile)
Non-vascular plants (bryophytes)  Small, grow in damp habitats, have rudimentary (inefficient) water conduction system. Some have hydroids which may partially conduct water  Gamete stage is dominant, heteromorphic alternation of generation  Gametangia produce gametes, gametes are surrounded by sterile cells to prevent dessication o Archegonium (skinneier and smaller), female sex organ contains egg o Antheridium (wider and bigger), male sex organ producing sperm  3 groups (liverowrts, hornworts (stomata present), mosses (algal like))
seedless vascular plants  sporophyte/diploid domiant phase of life cycle, true stems, roots, leaves, ground tissue, colonize land  free living (not attached to gametophyte)  two types of spore production o homospory:spores producesd are same,develop into gametophyte that posses both sex organs o heterospory: sporse produced are morphologically distinct  megaspores: larger and produce female gametophyte and only egg  microspores: smaller, produce male gametophyte and only sperm  younger ones have true roots and leaves while older ones don’t o microphyllous (club mosses, spike mosses, and quillworts) o megaphyllous (ferns, have clusters of sporangia (spori), sperm swim through water
vascular seed plants  desired traits of seed plants o reduced gametophytes, heterospory (micro and megaspore), ovules, pollen, seeds o fertiliztion of egg and sperm into diploid zygote  gymnosperms (non-flowering) o dominant sporophyte stage o megasporangium, yieds 4 megaspores, only one becomes female gametophyte o microsporangium:produces lots of microspores, one will find egg  pollen transported by went, trapped by sticky droplet, pollen tube germinates and grows toward egg  xylem has tracheids but no vessels, seeds have no endosperm  angiosperms (flowering) o dominant sporophyte stage, largest plant group o reduced female gametophyte=embryo sac o microsporangia called stamens, usually develop into a pollen grain, transported abiotically (wind/water) and biotically (birds, insects, mammals) o pollen tube (grows toward the embryo sac), pollen lands on top and tube grows in o micropile is the opening for the pollen tube to get to the egg o double fertilization  one sperm fuses with the egg, the second sperm fuses with several nuclei in the embryo sac to called nutritive tissue called endosperm o xylem contains tracheids and vessels o modifications of leaves  ovules are protected by the carpel, leaves roll in tubes, guard seeds from predators  receptacle: structuere bearing the top of the flower (like the stem)  perianth: two outermost series of sterile appendages  calyx: outermost series, made up of green leaf-like seapls  corolla: next series made up of petals  androecium: outermost of fertile appendages (stamens, the tubes on inside)  gynoceium: innermost set of fertile appendages, comprise of pistils  pistil has a stigma=top, style =middle, ovary=bottom, like a beaker o fruit  simple fruit=product of one pistil  compound fruit=product of several pistils  aggregate fruit: pistils from the same flower  multiple fruit: pistils form different flowers  fleshy fruit: fleshy texture  dry fruits: dry texture  dehiscent fruits: open  indehiscent fruits: closed
Floral modifications  Complete: all series present (plant parts)  Incomplete: one series absent  Naked: lacking skin/perianth  Perfect: both sexes present  Imperfect: lacking other androecium or gynoceium
Sexual conditions  Hermaphroditic: both sexes present in every flower  Monoecious: males and female flowers occur on same individual plant  Dioecious: male and female flowers occur o different plants  All complete or perfect flowers must be hermaphroditic  All imperfect or naked flowers must be incomplete  Perfect flowers are not necessarily complete  Hermaphroditic flowers can never be monoceious or dioecious 
Dependent assortment: alleles of two genes stay linked through the generations  Results from genes occurring on the same chromosome Incomplete dominance: RR=dark pink, Rr=pink, rr=white…pink can revert back to red or white Codominance: two genes are dominant and co-occur  Ex. human blood types  AO=A, BO=B, OO=O, AB=AB
Pleiotropy: when a gene affects many traits
Sex linked genes: when the gene is on the X or Y chromosome. Females can be carriers, men either have it or don’t
Jean Baptist Lamarck was first to suggest theory of evolution but suggested there was a mechanism that stated….  Characteristics aquired during an organism’s lifetime could be passed on (WRONG)  Darwin fixed that point
Homology: a trait shared by two species because both inherited it from a common ancestor
Homoplasy: similar traits evolved independently
Vestigial Traits: a structure that is reduced or incompletely developed and has no function
Fitness: ability to survive to produce offspring
Adaptation: a heritable trait that increases an individual’s fitness in a particular environment
Mutation: creates genetic diversity, essential for evolution, change in DNA
Hardy-Weinberg Principle: predicts the genotypes and phenotypes produced when an entire population interbreeds  Null hypothesis: indicates the genotypes/phenotypes when nothing special is going on  If something special going on , then false  p=frequency of allele 1 (phenotype)  q=frequency of allele 2 (phenotype)  p+q=1  2pq=frequency of heterozygous genotype  p^2=frequency of homozygous genotype for allele 1  q^2=frequency of homozygous genotype for allele 2  requires no gene flow, no mutations, no natural selection, large population size, random mating
Natural selection: certain alleles increase in frequency b/c they are associated with greater reproductive success
Directional selection: one end is really low, one end is really high
Stabilizing selection: extremes are really low, middle is high
Disruptive Selection: favors extremes, middle is low
Sexual selection: females choose most “showy” males, males fight over females
Genetic Drift: in small populations, allele frequencies can fluctuate unpredictable by chance
Founder effect: very small number of individuals migrate to a new area and establish a new population
Genetic Bottleneck: natural disaster
Gene Flow: immigration and emigration
Species: a distinct, identifiable group of populations that is evolutionary independent of other such groups
Prezygotic: factors before fertilization
Postzygostic: factors after ferilization
Hybrid animals (ex. mule) are infertile and cnat produce
Morphospecies concept: population is different morphologically from other populations
Phlogenetic species concept: smallest monophyletic group on a phylogenetic tree
Allopatric mechanisms: populations geographically separated  Dispersal: some individuals leave their population and colonize a new habitat (founder effect and genetic drift occur  Vicariance: population split into two by a geographic boundary
Sympatric mechanisms: populations co-occur
Phlyogenetic classification  Kingkingdom  Phillipphylum  Cameclass  Overorder  Forfamily  Grapegenus  Sodaspecies
Sister species: two species right next to eachother
Polytomy: more than 2 branches emerging from one node (shows uncertainty)
Outgroup: species that branches off way easy and doesn’t have any ancestors
Monophyletic group: one-snip test, single species and all species descended from it
Synapomorphies: traits that first evolved in the ancestral species in a monophyletic group and were passed on to all descendant species
Alternate ways to draw a phylogenetic tree: can flip it, swap sister brnaches, swap whole branches, as long as spin aoround the node its fin
Adaptive radiation: a rapid evolutionary diversification in which one lineage leads to numerous descendants that are diverse in form
Ways of eating  Heterotrophs: aquire energy by ingesting organic material o predators, tentacles
triploblast (3 tissue layers)  protostomes o lophotrochoozoa  platyhelminathes  flat body, large surface area, live in moist environment  flat warmstapewarmes, flukes, tuberallians  sometimes parasitic  annelidia  chatae: bristle like extensions  segmented warmspolychaetes, oligochaetes, leeches  mollusca  foot: locomotion  radula: tongua for deposit feeding  hard shell secreted by mantle  bivalvia (2 halves hinged together), gastropoda (snails), chitons (8 shelly plates  rotifers  damp soils, coronoa of cilia that make a crown  suspension feeders  bryozoa  encrust rocks, docks  brachiopoda  attach to rocks, like bivalves but aren’t o ecdysozoa  tardigrada  water bears, survive crazy environments  onychophora  caterpillars  moist environments, segmented body  anthropoda  jointed limbs  chitinous exoskeleton  segmented body has tagmata (head, thorax, abdomen), sometimes has cephalothorax (2 body segmentstagmenta and has cepla  hemocoel: body cavity that provides space for internal organs  grow by molting  compound eyes with many lenses, antennae  jointed appendage serve many different functions (walking, swimming, flying…etc)  myriapods (centipedes), insecta (have appendages on mouth), chelicerata (horshoe crab/sea spiders/scorpions, spiders), crustacea (lobsters, crab, shrimp, barnacles…double anntanea), trilobites (famous extinct bug)  nematodes  cover everywhere, abundant, cause elephantis and trichinosis, unsegmented, simple  deuterostomes o echinoderms  radially symmetric, calcareous skeleton, marine  water vascular system: series of tubes that is like a hydrostatic skeleton  tube feet: tubes project to the outside environment, lets water into body, reson why cant go into freshwater  crinoidea (feather stars and sea lilies)  asteroidean (sea stars)  Ophiuroidea: brittle stars and basket stars  Echinoidea: sea urchins and sand dollars  Holothuroidea: sea cucumbers, churizo shaped o Chordata  Pharyngeal gil slits=opening to throat  Hollow nerve cord on dorsal side  Notochor: supportive but flexible rod on dorsal side for swimming  Tail  Cephalochordates: small fish  Urochordates: lose all characteristics when grow up, sea squirts and salps o Vertebrates  Cartilaginous/bony vertebrae protecting spinal cord  Cranium (skull)  The earliest fish were jawless, the jaw allowed fish to diversify (evolved from gill arch) o Chondrichthyes: sharks and rays o Actinopterygi: ray finned fish o Lobe-finned fish  Coelacanth: deep ocean  Lung fish: omnivorous (both meat and veggies), can hibernate and dig into dirt in water   Dinosaurs (extinct)  Originally in Triassic period, then larger in Jurassic and cretaceous, herbivores and carnivores, a lot had feathers (ex. velociraptor)  Birds evolved from dinosaurs  Use feathers for staying warm, keeping eggs warm, flight/gliding  Endothermic (warm blooded while ectothermic is cold blooded)  Flying adaptations(ex. keel on sternum) horny beak instead of teeth  Herbivorous and predators, emus cant fly  Archaeopteryx: first bird, many reptile characteristics  Mammals o Synapomorphies: fur (insulation), mammary glands (lactation-milk production), facial muscles and lips for sucking, lower jaw, endothermic (high metabolic rate-high activity) o Monotremes (platypus or porkypine (echidna)  Lay eggs, most basic group of mammals, Australia, lower metabolic rate, secrete milk but don’t have nipples, eat small animals, leathery beak o Marsupials: young develop in a pouch, suck milk in there, omnivores, Australia+America  Poorly developed placenta, so short and bad preganancy o Eutherians (placental mammals)  Longer pregnancy because placenta is well developed=young highly developed  Most diverse (rodents, bats, hoofed mammals, primates)  Extensive parental care, placenta=transfers gasses and nutrients to embryo o Marsupials and eutherians are viviparous (give birth to live young instead of eggs)  Allows the embryo to develop under more controlled conditions  Primates (placental mammals/eutherians) o Eyes in front of face for depth perception, grasping hands+feed, big brain, color vision, parental care o Prosimians (new world monkeys, lemur catta, old world monkeys)  Hominids (great apes) all except orangutangs live on ground  Homo sapiens are extinct relatives, evolved out of Africa
The History of Life  Fossil: any trace of an organism that lived in the past, provide direct record of history of life o Buried by sediments to protect the remains from destruction (hardens into sedimentary rock)  Trace fossils: tracks, trails, and burrows  Original biological material: sometimes preserved (ex. pollen grain, bones, shells)  Compression: the organic material is pressed by the weight of sedimeintes  Molds and casts: the original bioligcal material decays or dissolves, leaving an impression  Permineralization: dissolved minerals precipate in the pores of wood, bone, etc (turning into stone)  Fossil record is best in wet habitats and for decay resistant parts  Geological time scale- earth about 4.6 bya (dominanted by unicellular organisms, animals last 1/8th) o Time divided up into levels, intervals=extinction/evolution usually o Precambium Period  Hadean Eon: earth forms, water forms  Archean Eon: microbial life, bacteria + archaea  Early Proterozic Eon: oxygen released by photosynthetic cyanobacteria, microbes  Stromatolites in rocks: mounds of layered sediment  Middle Proterozoic Eon: eukaryotes/protists  Late proterozic Eon: animals o Camiran Period (time of visible life) 542 mya  Early Cambrian: Most modern phyla appear, fossils more common  Cambrian explosion: modern phyla appear, animals with hard skeletons  Paleozic Era: animals and lineages on land  Early Denovian: coal swamp, conifers, mammal like reptiles (tetrapods)  Late Cretaceous: Cenozoic: mammals, birds, angiosperms, dinosaurs killed off  Continents moving due to plate tetonics  Mass extinction: an increase in extinction rate that significantly reduces biodeversity o Dramatic changes in environment, 5 big ones in history, diverse groups went extinct o Ex. asteroid, volcanism, global warming, ocean assidification, anoxia (low oxygen, glaciation o The Permian extinction; basalt layers, volcanism  Basaltic volcanism: Permian aged lavas erupted  Environmental effects: lots of CO2- causes global warming and ocean assidfication anoxia, sulfur  Effects: mammal-like reptiles were dominant and went extinct, 90% marine went extinct  End-cretaceous extinction: dinosaurs went extinct and mammals came to power o Asteroid impact evidence, iridum sediments (rare and abundant in asteroids) o Effects of the impact  Dust cloud causes darkness, plants stop growing, animals lose food, vaporization of sulfur caused acid rain, widespread wildfires, tsunamis
Ecology: study of how organisms interact with each other and the environment  Understand how these interactions result in the observed abundance and distribution of organisms o Oceanic zone: deep water zone beyond continental shelf, nutrients scarce, low productivity o Benthic zone: bottom of the oeaan, low productivity, no light o Upwelling zone: currents carry nutrient-rich deep water upwards (high productivity) o Lakes: mostly freshwater, few salty, photic vs aphotic zones and benthic zones  Littoral zone: light reaches lake bottom (rooted plants)  Limnetic zone: offshore waters in the photic zone  Lake Turnover: cold dense water at bottom, shallow (less dense water) in photic zone cant mix with this, as water warms/cools in the spring/fall the surface water gets dense and sinks so lake waters mix (enhances productivity) o Wetlands: shallow water, plants grow up on land, soil saturated with water, plants adapted o Streams and Rivers: unidirectional water flow, near source water is fast nutrient pour, high in O2, water slows down becoming warmer and more nutrient rich, and lower in O2 o Estuaries: where rivers meet ocean, high productivity  Distribution of organisms o Abiotic factors: a species can only be adapted to a certain range of physical conditions o Biotic factors: interactions with other organisms, limited by disease, competitors, predators o Historical factors: geographic barriers, wallace’s line (marks deep ocean trench) o Invasive species: human’s activities are increasing the dispersal of organisms among diff groups
Behavior: any action by an organism, response to a stimulus (piece of info gathered about the environment)  Proximate (how)-how do they navigate at night  Ultimate (why)-why do they forage at night?  Behavior influenced by both genetic and environmental factors, can evolve by natural selection  Cost-benefit analysis: behaviors that improve fitness are preferred o Optimal foraging theory animals make decisions that maximize the intake of usable energy  Foraging: looking for food  Choosing a mate: females invest energy in reproducing and parenting, females picky about mates, need a man who can contribute good alleles and lots of resources to offspring  Migration: long distance movement of a population associated with the change of seasons o Piloting: use familiar landmarks o Compass orientation: movement in a particular direction using sun, stars, earth’s magnetic field o migrate so can accomplish successful foraging  communication: any process in which a signal from one individual modifies the behavior of another o single must be acted upon…tactile(touch), olfactory (smell), acoustic (sound, visual o honeybee communication: if a bee finds a new source of food, more bees show up o Karl von Frisch did experiement and showed bees communicate by dancing  Waggle dance: circles plus straight line..round dance: circular motion o Dishonest communication: tricking prey, generally works, rare  Cooperation o Most behaviors benefit organisms o Altruistic behaviors: decrease fitness of self, increase fitness of other (sacrificing yourself)  Like a body guard, do for closest relative  Ex. prarie dogs giving alarm or sterile worker bees working for queen/mother o Kin selection: natural selection that favors altruistic behaviors directed at close relatives
Community: all the species that interact with each other in a given area  Competition: individuals share resources, lowering fitness of both o Intraspecific competition: competitors within members of the same species, causes density dependent growth (logistic) o Interspecific competition: competition between members of a different species who use same resources  Competitive exclusion: when 2 species compete, one may eliminate the other  Co-exist: species find niches, don’t compete  Keystone species: large effect on community  Fitness tradeoff: no one is perfect at everything  Consumption: one organism eats nutrients from another, consumer increases, victim decreases o Herbivory, parasitim, predation o Defenses: camoflauge, schooling (#’s), weaponary, mimicry  Mullerian mimics: look dangers, are dangerous  Basterian mimics: look dangerous, not dangerous  Mutualism; both increase in fitness o Flowering pants and pollinators, ants and acacia trees o Self interest, benefit to other is incidental, not intended  Commensalim: one species benefits, other is unaffected  Structure of communities o Biological communities are stable and contain a predictable set of species o Biological communities are dynamic, every-changing, and chance plays a major role in what species occur  Disturbance: any event that removes some individuals or biomass from a community o Biotic (predation, grazing, trampling o Abiotic (fire, storm, etc) o Can drastically change community, common o Global water cycle: precipitation and evaporation  wind blows evaporation from ocean and causes it to sometimes precipitate on land o Global nitrogen cycle: bacteria turn unusable gas into usable gas  Humans artificially fix N for fertilizer o Global carbon cycle: the burning of fossil fuels releases carbon from within the earth into the atmosphere  Coal: carbon left over from ancient buried plants  Oil: the buried hydrocarbons left over from ancient phytoplankton  The greenhouse effect o CO2, water vapor, and other gasses trap heat o Overall, this is a good thing, most of the planet would be frozen otherwise o Changes in the concentration of greenhouse gases cause changes in climate
Conservation Biology  Many species have died due to human actiities (ex. passenger pigeon)  Biodiversity- the diversity of life o Genetic diversity-the diversity of alleles present in a population, species, or group of species o Species diversity-the diversity of species in a region o Ecosystem diversity-the range of ecosystems present in a region o Phylogenetic diversity-some species have many close relatives  Others are only distantly related to any other species  It may be more important to preserve a species that represents a unique branch  about 1.5 million species on earth (1/2 insects), vastly underestimated  most biodiversity found in tropics  extinction: 6th mass extinction (adding to the 5th one, happening right now  why are endangered species endangered o invasive species  introduced by accident or on purpose  free from natural predators, pathogens, competitors  some spread rapidly, driving other species to extinction through predation, competition, etc  ex. brown tree snake got loose in guam and killed off lots of birds  not native species in area (dominate a region) o overexploration (overhunting, overfishing)  the harvesting of wild populations faster than they can replenish  often associated with fishing and hunting  large animals with low reproductive rates are particularly vulnerable o climate change  loss of habitat for cold-climate species in polar and high-altitude regions  extinction of species that cannot migrate fast enough as their preferred habitat shifts  coral (cnidarians) “bleeching” loss of mutualistic algae  ocean acidification from increased carbo dixoie levels, can inhibit shell and skeleton formation by corals, crustaceans, mollusks, etc o habitat loss: conversion of natural habitats to farms, ranches, etc  two problems  deforestation (logging, burning)  loss of primary (old-growth) forests  occurring in highly diverse tropical rain forests  damming rivers  dredging or filling estuaries and wetlands  converting prairies to farms and ranches  mining  building houses, roads, malls, golf courses, etc  habitat fragmentation  habitat fragmentation  as habitats are destroyed, they are also fragmented into small isolated fragments  threats from fragmentation o many species need a large area in which to feed and reproduce o individuals have trouble moving from one habitat to another o small isolated populations are more likely to go extinct o fragmentation creates a lot of edge habitat, which is unsuitable for many species o biomass declines sharply along edges of forest fragmentation  what happens in small, isolated populations o chance events (storms, diseases) are more lkely to eliminate a small population  if the population is isolated, the area is less likely to be recolonized from the metapopulation o genetic drift is strong in small populations  genetic variation wil be lost due to chance