Plants Humanity and Environment - Botany - Study Guide | BOT 131, Study notes of Botany and Agronomy

Download Plants Humanity and Environment - Botany - Study Guide | BOT 131 and more Study notes Botany and Agronomy in PDF only on Docsity! Botany 131 Study Guide BB Science + Scientific Method Fact [[ something believed to be true through observation and measurement ]] Hypothesis [[ educated guess or working assumption about something - only useful if testable ]] Theory [[ in “science”, conceptual framework based on many observations, used to explain observations and predict new ones ]] Science [[ a METHOD for understanding the natural world in an unbiased way ]] Scientific Method 1) Recognize question 2) Develop “testable” hypothesis (educated guess) 3) Design and perform experiments to gather data, testing the hypothesis 4) Analyze and interpret results. Was hypothesis supported? Both YES and NO answers useful. 5) Share/Use the knowledge (PUBLICATION) 6) Based on results, recognize more questions Characteristics of Scientific Method 1) Unbiased (at least it’s supposed to be) 2) Typically quantitative but can be qualitative 3) Uses proper experimental design to test hypotheses 4) Statistics used to analyze data, 95% usually sufficient to convince, 99% is better 5) Replication, replication, replication 6) Peer review before publication 7) Publication allows testing and critique from others Teleology [[ explains nature based on design or purpose ]] - Greek: telos (end of purpose) - logos (study of) - Aristotle used it Teleology Question Q. Why are flower petals colorful? • Teleological (implies purpose): 1) In order to attract pollinating insects 2) For humans to enjoy them 3) So that hummingbirds can find them • Non-teleological (mechanistic): 1) Because they contain compounds that absorb certain wavelengths of light and reflect others 2) Because natural selection has resulted in plants with those petal colors Conflict of Teleology - conflicts with scientific method and scientific way of thinking --> it offers no helpful insights into how things work or how things got that way Science and Proof - Science cannot “prove” anything! - But the “scientific method” is the best method humans have developed to “try” to understand the natural world. -------------- CC LIFE CYCLES + ALTERATION OF GENERATIONS Somatic Cells - a.k.a. “body cells” - are DIPLOID Diploid [[ (2n): cell with 2 sets of DNA in nucleus ]] - 1/2 of DNA comes from mother - 1/2 of DNA comes from father Reproductive Cells - are HAPLOID Haploid [[ (1n): cell with 1 set of DNA in nucleus ]] Cell Division - two types occur in plants & animals 1) Mitosis 2) Meiosis Mitosis - 1 cell divides 4) Angiosperms Bryophytes [[ seedless, non-vascular land plants ]] - dominant generation: GAMETOPHYTE - require water during reproduction (swimming sperm) - types: --> Mosses --> Liverworts --> Hornworts Review Plants maybe evolved from “green algae.” Bryophyte: Seedless non-vascular plants w/ dominant gametophyte --> reproduces in water --- EE Plant Diversity Ferns & Fern Allies [[ seedless vascular plants ]] - dominant generation: SPOROPHYTE - sorus on underside w/ sporangia inside Fern Structure & Reproduction - sporophyte -> spores - SORUS on fern’s underside --> contains many SPORANGIA - sporangia -> SPORES [ sorus -> sporangia -> spores ] - spores divide & grow -> GAMETOPHYTE - gametophyte -> GAMETES --> gametes -> ZYGOTE -> sporophyte Review - fern: seedless vascular plant ((sporophyte)) --> sorus on underside w/ sporangia inside --- FF Plant Diversity Gymnosperm [[ vascular plant that can make seeds ]] - dominant generation: SPOROPHYTE - make NO flowers --> seeds develop naked --> ex. pine nut seeds - needle-like leaves - softwood Angiosperm [[ vascular plant that can make seeds ]] - dominant generation: SPOROPHYTE - make flowers --> seeds develop in fruit --> ex. pomegranate seeds - broad leaves - hardwood - dicot or monocot Cotyledon [[ tissue joined w/ embryonic sporophyte ]] --> transfers nutrients from endosperm to embryo 1) Monocots (1 cotyledon) ex. coconut seed 2) Dicots (2 cotyledon) ex. peanut seed Seed [[ dispersal unit containing embryonic sporophyte (baby plant) + nutritive tissue surrounded by protective seed coat ]] --> seed = baby plant w/ giant backpack of food Seed vs. Spore - embryo is COMPLETE plant --> spore is a single cell - embryo PROTECTED in seed --> spores are unprotected - embryo has FOOD supply in seed --> spore has no extra food Review Gymnosperm: vascular plants -> seeds naked ((sporophyte)) Angiosperm: vascular plants -> seeds in flowers ((sporophyte)) --> monocot or dicot Cotyledon: tissue that transfers nutrients from endosperm to embryo Seed: dispersal unit w/ embryo & nutritive tissue in protected seed coat --> has many advantages over spore (complete, protected, food) --- GG Plant Cells + Tissues + Organs Cell Theory [[ cell is smallest unit of life + all cells come from pre-existing cells ]] Cell Structure - surrounded by plasma membrane --> composed of lipids, proteins, and some carbohydrates PROTOPLASM: interior --> includes nucleus, cytoplasm & everything else --> subdivided into membrane-bound organelles CELL WALL: exterior --> made of cellulose Cotton - “plant cell walls” - most important textile fiber in the world - accounts for 80% of natural fiber used - cotton seed also used for cooking oil --> mostly for potato chips and other chips Cells Division - meristems: cell division @ specific regions of plant --> vascular meristems --> apical meristems Tissue - cells organize into tissue 1) Dermal - outer skin |--------------| 2) Vascular - plumbing |=======| 3) Ground - everything else |xxxx| Organs - tissue organize into organs 1) Vegetative Organs --> ex. roots, stems, and leaves 2) Reproductive Organs --> ex. flowers Vegetative Organs - main types of root systems 1) Taproot (long & thin) --> anther (|) & filament (˚) 3) Petals (corolla) 4) Sepals (calyx) --> receptacle Flower Structure Complete : ALL 4 parts Incomplete: MISSING one or more parts Perfect: BOTH male and female parts Imperfect: Male or female part MISSING Flower Types Monoecious: have female + male flowers on SAME plant --> ex. corn Dioecious: have female + male flowers on DIFFERENT plants --> ex. pistachio Flower Peduncle [[ stalk which has flowers arranged on it ]] - has its end at... 1) SINGLE flower 2) CLUSTER of flowers (inflorescence) Flower Sexual Reproduction - Pollination: transfer of pollen 1) self (same plant) 2) cross (2 different plants) - Fertilization: when sperm & egg fuse - After Pollination: --> pollen (male gametophyte) grows toward --> the embryo sac (female gametophyte) Flower Fertilization [[ sperm & egg fuse ]] - embryo encased with cotyledon (food reserves) --> endosperm: backpack of food - monocot: corn grain - dicot: peanut seeds Fruits [[ mature ripened ovary (containing one or more seeds) ]] - FERTILIZED ovule developed into a seed(s) - ex. pea pod: fruit, pea: seed Fruit Types 1) Simple: single/several FUSED carpels --> ex. single: peach, several: orange 2) Aggregate: single flower w/ SEPARATE carpels --> ex. raspberry, blackberry 3) Multiple: many FUSED flowers on SINGLE stalk --> ex. pineapple, mulberry 4) Accessory: receptacle becomes part of mature fruit --> ex. apple, strawberry Review Asexual: clone offspring Sexual: unique offspring Flowers: carpel + stamen + petals + sepal Flower-> complete, incomplete, perfect, imperfect Penduncle: stalk with flower(s) on top of it Fruit: Ripened ovary Fruit-> simple, aggregate, multiple, accessory Seed: Fertilized ovule --- II Biodiversity & Classification General - species were organized before as only ANIMALS or PLANTS --> now there are classified more specifically - 15m diff. species exist today compared to 15b. species before --> 99% extinct, only 1% exist today Definitions Species: reproductively isolated group of organisms --> has common gene pool & similar physical attributes Taxonomists: whom describe, name, group organisms Systematists: whom figure evolutionary relationships --> between organisms Naming System - Binomial System of Nomenclature --> created by taxonomist Carl Linneaus - 1st letter is capitalized, all is in italics --> ex. Zea mays Classification - old classification: based on form/observable chars. - modern classification: based on DNA/genetic chars. Classification Today 1800s: 1) animalia, 2) plantae 1860s: 3) protista (all other than 1 or 2) 1938: 4) monera (bacteria subtracted from protista) 1969: 5) fungi (subtracted from protista) 1980s: monera: bacteria (sick) & archaea (extreme areas) 1) Animalia 4) Bacteria 2) Plantae 5) Archea 3) Protista 6) Fungi -scientists propose 3 domains: bacteria, eukarya, archaea --> eukarya has everything else --- JJ Heredity & Evolution Heredity [[ inheritance of traits from parent to offspring, transmitted through DNA ]] Genotype: genetic makeup of individual (DNA) Phenotype: physical appearance of individual (color, height, etc) Gregor Johann Mendel - 1800s: proposed... --> inheritance results from “transmission of specific units” of inheritance - now known as GENES Gene - region of DNA that codes for specific a protein - occur in pairs called ALLELES --> 1 gene from mom, 1 gene from dad - polygenes: many traits controlled by many related genes --> each polygene contributes to phenotype --> fruit color, plant size, fruit size, etc 4 Principles of Inheritance 1) Inherited traits transmitted by genes --> homozygous: both alleles are IDENTICAL --> heterozygous: both alleles are DIFFERENT 2) Principle of Dominance: --> 1 allele is “usually” dominant 3) Principle of Segregation: --> each gamete (egg/sperm) carries only 1 of the 2 alleles Amino Acids - 20 different amino acids make up protein - nonessential: human cells can make them (11 kinds) - essential: humans need to eat them (9 kinds) Lipids [[ organic molecules insoluble in water ]] - include fats & oils --> triglycerides (storage fats) --> steroids (precursors to hormones) --> membrane lipids (phospholipids) - contain fatty acids --> saturated: pack together tightly, solid (ex. lard) --> unsaturated: pack together loosely, liquid (ex. olive oil) Vitamins & Minerals - found in small concentrations in plants --> fat-soluble: vit A, D, E, K (veggies) --> water-soluble: vit B1, B2, B3 --- LL Origins of Agriculture Origins of Agriculture - archeological evidence shows humans existed for 250k yrs - hunting/gathering were means for gathering food 10k yrs ago - early plant breeders did simple things: 1) select seed from largest/best producing plants 2) controlled breeding... led to new types of plants Domesticated Plants - genetically very different from wild relatives - need human help to reproduce, unlike wild plants --> ex. wild grass has shattering panicles to disperse grain --> ex. domesticated has non-shattering panicles (can be harvested) - greatly reduced genetic variability compared to wild relatives --> HUGE problem for breeding plants in future Conservation - conserving wild relatives of domesticated plants is important - humans developed “seed bank” to store seeds for future - but catastrophes (flood, lack of electricity, rotting) can ruin seeds - as a result of that, Global Seed Vault was created Global Seed Vault [[ place for long-term storage of seeds in Arctic ]] Agricultural Problems - sedentism - poor diet (little variety) - excessive resource use - dependence on monocultures - CONTROL OF FOOD BY A FEW GROUPS --- MM Genetically Modified Foods GMO [[ genetically modified organism ]] - DNA has been altered - types: --> transgenic: contain DNA is of another species --> cisgenic: contain no DNA from other species - ex. GM yeast to grow antifreeze proteins --> based on gene from cold water arctic fish Eutrophication [[ excess nutrients such as phosphorus & nitrogen in bodies of water ]] 1) Trigger excess algae growth 2) Algae die 3) Bacteria consume algae & consume dissolved oxygen 4) Lack of oxygen kills fish + other organisms in water Enviropig [[ GM Yorkshire pig able to digest plant phosphorus more efficiently ]] - has PHYTASE gene --> came from e-coli bacteria & a promoter gene from a mouse - phytase protein breaks down phosphorus compounds --> allowing pig to absorb more phosphorus - designed for humans to eat, though not available yet Potential Danger - companies DON’T have to have human trials to test safety of transgenic meat --> according to current guidelines - transgenic Atlantic salmon w/ genes from cold-water Chinook salmon grows faster --> without safety testing on humans - GM salmon escapees, in 40-60 generations, COULD wipe out wild salmon populations BT Corn - GM corn that contains gene (BT toxin) from bacteria --> poisonous to insects - makes its own pesticide in EVERY cell of the plant - found to DAMAGE stream ecosystem - could contaminate wild populations = could be disastrous! Gold Rice - contains three new genes, including one from daffodils - produces Beta-carotene in the grain - presumably will help solve blindness in children deficient in vitamin A --> in societies that have a rice-based diet Gold Rice Disadvantages - not enough vitamin A in golden rice, need 12x more rice in diet to satisfy requirement - over 70 patents are pending on who owns it - people don’t like it - white rice is an advertising gimmick... inspired people eat “polished” rice - eating “unpolished” rice is better but people would not like to eat yellow rice - human food safety is unknown - contamination of wild relatives is a huge potential problem Roundup Herbicide - invented by Monsanto - contains GLYPHOSATE --> chemical that kills plants by stopping synthesis of certain amino acids in plants - only be used by “roundup ready” plants --> plants end up harmful to environment 1) Super-weeds, requiring even MORE Roundup 2) Toxic to animals --- NN Agriculture Sustainability Agriculture Sustainability [[ “feed” ourselves today w/o compromising future generations’ ability to “feed” themselves ]] Green Revolution 1) Crops deplete nutrients in soils 2) Nutrients replacement required 3) Fertilizers used to replace nutrients - # on Fertilizer: nitrogen-phosphorus-potassium Soil Erosion - major problem for agricultural soils - US: erosion removes soil 16x faster than it is formed - caused by... --> off road destruction “cruising” --> overgrazing --> excessive/uncontrolled logging 1930 Dustbowl in USA - occurred because of change in climate & abuse of land --- PP Grasses & Legumes Wheat - evolved in the Middle East - domesticated wheat? --> result of hybridizing several species of wheat & other closely related grasses - whole grain’s structure 1) bran (coat) 2) starch (inside) 3) germ (embryo) Wheat Ploidy - ploidy of plants can vary - diploid: einkorn wheat (14 chromosomes) - tetraploid: pasta wheat (28 chromosomes) - hexaploid: bread wheat (42 chromosomes) Wheat Types - Durum Wheat --> adapted to colder climates (Northern US, Canada, South Europe and parts of India) - Bread Wheat --> 90% of wheat grown throughout world. --> has highest gluten content 1) hard bread wheat: higher gluten content 2) soft bread wheat: lower gluten content Corn - evolved in Mexico - type of corn determined by type of carbohydrate content in grain --> ex. popcorn, flint, dent, sweet, waxy, etc - DENT corn is basis of the fast food industry - male flowers on top of stem - female flowers on lower part of stem Hybrid Corn - results in phenomenon called “hybrid vigor” (heterosis) --> increased size/fitness of heterozygous hybrid --> better than its homozygous parents Rice - evolved in lowland tropical areas in Asia - grows in flooded fields --> brown: whole grain, white: milled to remove bran/germ - feeds more people on earth than any other crop --> ONLY major crop grown exclusively for human food