Midterm #2 LIFE 103
Midterm #2 LIFE 103 103
Popular in Life 103- Biology of Organisms
verified elite notetaker
Popular in Biology
This 18 page Study Guide was uploaded by email@example.com Notetaker on Saturday March 5, 2016. The Study Guide belongs to 103 at Colorado State University taught by Tanya Dewey in Winter 2016. Since its upload, it has received 106 views. For similar materials see Life 103- Biology of Organisms in Biology at Colorado State University.
Reviews for Midterm #2 LIFE 103
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 03/05/16
Midterm # 2 Study guide Phylum Gnetophyta -has 3 genera -tend to thrive in desserts and tropics -cones are fleshy Genus Ephedra -located in the Southwest dessert -uses: meth Genus Welwitschia -located only in Southwest Africa -2 leaves keep growing and will split, giving appearance that there is more than just 2 leaves -endangered, have the ability to live hundreds of years Phylum Coniferophyta -largest gymnosperm phyla -majority are evergreens -photosynthesis during all seasons -sailors planted the North American pine on islands to use them for masts if they ever got stranded Douglas fir -used for housing development European larch -located in Swiss Alps Bristlecone Pine -located in California and Colorado up in the mountains -Grow very slow, enabling them to live thousands of years. Sequoia -largest organism based on volume and mass -Climate change threatens its existence Wollemia pine -naturally found in Australia -thought to be extinct Lazarus effect Common Juniper -used for spice and gin In case of gymnosperms, the tree would be the sporophyte -Sporophyte is 2n -Microsporangium (2n) are inside the cones -Pollen grains are (n) -Pollen grains go through meiosis when they land on the ovule Angiosperms 5 traits of seed plants 1. Reduced gametophytes (microscopic gametophytes protected by sporophytes) 2. Heterospory (spores of 2 sexes) 3. Ovules 4. Pollen 5. Seeds Angiosperms have one phylum, the anthophyta. -have flowers, fruits, and seeds Flower -Tend to have successful reproduction because they attract pollinators and animals. This makes flowers very diverse. -have different colors, scents, and symmetry Amorphophallus titanium -largest unbranched inflorescence -blooms for a few days -corpse flowers fragrance imitates rotting flesh to attract flies for pollination -located in Sumatra -can rach 6ft tall RAfflesia schadenbegiana -corpse flower -largest florescence in diameter -blooms for 5 days -located in Indonesia and Malaysia Wolffia Arrhizia -smallest angiosperm Sepal-modified leaf that surrounds the bud Petal-modified leaf Stamen and carpel- highly modified leaves Carpel -has the ovary, style and stigma -stigma receives pollen -style is where pollen lands Pistil fused carpels Female gametophyte embryo sac that develops in the ovule Stamen Has the microsporophyll, anther, and pollen sacs (also known as microsporangium) Complete Flower -has all 4 modified leaves (petals, sepal, carpel, stamen) Incomplete flower -don’t have 1 or more of the modified leaves Perfect flower -has male and female parts All complete flowers are perfect flowers, but not all perfect flowers are complete Selfing plants plants that are able to pollinate themselves. -perfect plants can self-pollinate Ways to prevent selfing -gametophytes are incompatible -pollen tube doesn’t grow due to certain proteins -stamens and carpels can be different lengths -sporophytic self-incompatibility the sporophytes fail Pollen -dispersal method influenced shape and function of pollen grains -outside of pollen has sporopollenin Life cycle of angiosperm 1. Microsporophytes (2n) undergo meiosis and produce a microspore (n) 2. Ovule (2n) undergoes meiosis and produce megaspore (n) 3. Pollen grain land on stigma, grows down to ovary and 2 sperm enter the egg, fertilizing it 4. Have a zygote (2n) and triploid tissue (3n) becomes endosperm that provides nutrients 5. Embryo is (2n) and breaks loose of seed coat (2n) and germinates Cotyldons -1 or 2 first seed leaves in angiosperms -2-24 for gymnosperms Hypogeal cotyledons -aren’t able to photosynthesize because they are underground -function store starch Epigeal cotyledons -photosynthesize because they are above ground -when seed is germinated, the epigeal cotyledons break through the seed coat Fruit -ovary that has matured -can be fleshy or dry -function seed protection and dispersal Simple fruits -single or compound ovary -in a single carpel Simply fleshy -berries, drupes -Berries single ovary Ex bananas, oranges, blueberries, tomatoes Pipo watermelons, squash, pumpkins. Special berries with a tougher exterior -drupes exocarp and mesocarp is fleshy, but has a hard endocarp. Ex stonefruits, coconuts, mangos, olives Aggregate -single flower with many carpels -blackberries Multiple -Inflourescence several flowers fuse together -Every fruit came from one of those flowers -Fruits merge together -pineapple and figs (in figs, the flower is inside and is pollinated by the fig wasp) Bread fruit Joseph Banks wanted to bring this fruit to provide substantial food to slaves. But his sailors mutinied and remained on the island. By the time Banks brought back the bread fruit trees, slaves was abolished Simple dry fruits -dandelions and dots on strawberries Legume -clover, peanuts, beans, soy -Aspergillus fungus that attacks peanuts and causes liver cancer Nut -The wall of the ovary turns into a hard coating/shell Indacesent don’t open when mature -acorns Angisoperm diversity 1. Monocots once cotyledon 2. Eudictos 2 cotyledons and “true” dicots Basal Angiosperms -3 oldest lineages 1. Amborella trichopoda 2. Star Anise 3. Water lilies Magnolids -closer in relation to monocots and eudicots than basal angiosperms -Laurels, black pepper plants, magnolias Monocots -make up 25% of angiosperms -60,000 species -Multiples of 3 -Parallel veins Palms -around at end of the Cretaceous period -2,600 species -Tropical -Talipot palm Larges inflorescence due to their leaves being 5m in diameter. They produce once then they die Grasses -10,000 species -Family Poaceae -Bamboos, wheat, sugarcane, rye, maize Orchids -22,000 species -bilaterally symmetric -could be largest family of angiosperms. Asteraceae is a close second Eudicots -2/3 of angio sperms -2 cotyledons -veins are net like - vascular tissue arranged in a ring -taproot -3 openings on pollen grain -multiples of 4 or 5 Angiosperms and animals -Flowers that are bilateral symmetrical tend those have more species than those that are radially symmetrical. -Why? -Bilateral can be more specific to certain pollinators -Bilateral tend to affect the movement of pollinators more than radial -Gene flow is decreased in diverging populations Plants and people -seed plants are packed with nutrients important for human civilization -80% of food crops are wheat, rice, maize, potatoes, cassava, and sweet potatoes -Artificial selection has led to modern crops Threats to biodiversity -loss of habitat (affects both plants and animals) -within 100-200 years, we could lose 50% of plant species Plant structure 3 main organs 1. Roots transport water and minerals 2. Stems used for support 3. Leaves transport sugars Roots -multicellular -anchor the plant -absorb water and minerals -store nutrients Root hairs -increase surface area to absorb more water and minerals Taproot -1 main root -lateral roots branched Advenitious roots arise from stems or leaves. Includes… 1. Fibrous roots a. Seedless vascular monocots 2. Proproots a. Aerial roots b. Provide support 3. Strangling roots a. Support plant by growing around objects b. Strangler fig i. Epiphytes ii. Roots grow down and around the tree iii. Stem grows up 4. Climbing roots a. Provide support b. Negatively phototrophic grow towards darkness and away from light stimulus Pneumatophores -roots that grow above ground -allows for gas exchange in wet and flooded environments -common in mangroves Buttress roots -provide support Storage roots -taproots -lateral roots -store carbohydrates Haustorial roots -parasitic plants -use other plants to obtain water and nutrients -Ex mistletoe, dodder, snow plants Stem -nodes place where leaves are attached -internodes part of stems that are between the nodes Axillary bud -produce a lateral shoot or branch Apical bud -located at shoot tip -helps young shoots grow taller and elongate Modified stems Corm -storage stem located beneath the surface -Ex taro, gladiolus, saffron Rhizome -horizontal -beneath he surface -sends out roots and shoots -Ex ginger, poison grass, Bermuda grass Stolon -horizontal along the top of the ground -advenitious roots -at the end of each stem is a clone -Ex strawberries and several grass species. Bulbs -underground stems -modified leaves -function storage during periods of dormancy -Ex garlic and onions Leaves The leaves of most vascular plants are the main photosynthetic organ Types of leaves 1. Simple leaf single leaf per stem 2. Compound leaf complex petiole 3. Double compound leaf has several leaflets Modified leaves Bract -part of reproductive structure -tend to be brightly colored -usually confused as the flower, but it’s not the flower Ex poinsettia Tendrils -function climbing and attaching to surfaces -can photosynthesize -thigmotrophic stimulus is touch Ex pea plant Spines -modified leaf -used for defense -seen in xeriphytes plants that prefer dry environments Thorns -modified stem Prickles -modified epidermis -Ex roses (the nomenclature usage of thorns referring to roses are actually prickles) Storage leaves -store water, nutrients, and toxins Succulents -cacti -iceplants -agave 3 types of tissues -Dermal -Ground -Vascular Dermal tissue Epidermis on non-woody plants Cuticle a waxy coat that minimizes loss of water from the epidermis Periderm -also in woody plants -protective tissue -the epidermis in older regions of stems and roots get replaced by periderm Trichomes- small hairs on the shoot that prevent insect damage Vascular tissue -moves materials back and forth between the roots and shoots over long distances -2 types of vascular tissue xylem and phloem Xylem moves water and minerals from roots to shoots Phloem move nutrients to where they are needed most in the plant Stele vascular tissue of a stem or roots -solid cylinder stile in rots of angiosperms Ground tissue -neither dermal or vascular -pith ground tissue internal to vascular tissue -cortex ground tissue external to vascular tissue -ground tissue can function as storage, support, and photosynthesis Cellular structure in plants 5 types 1. Parenchyma 2. Collenchyma 3. Sclerenchyma 4. Xylem water cells 5. Phloem sugar cells Ground tissue is composed of… 1. Parenchyma 2. Collenchyma 3. Sclerenchyma Parenchyma -primary walls are flexible -has a central vacuole -used for storage -photosynthesizes -can divide and differentiate -doesn’t have secondary walls -least specialized Collenchyma -strands -provide structural support for young plants - walls are thick and uneven -doesn’t have secondary walls -not as flexible as parenchyma, but a little flexible so that it doesn’t restrain growth Sclerenchyma -rigid -does have secondary cells walls -when cells mature, they’re dead 2 types 1. Sclereids a. Irregular and small shape b. Thick and lignified secondary walls c. Provides the hardiness in nutshells and seed coats 2. Fibers a. Long and slender threads b. In flax and hemp Cells gets energy to build large cell wall, but in order for nutrients to flow, the cell must die at functional maturity. They still provide structure even when dead Vascular cells Tracheids -in all vascular plants -tubular, long and dead -water moves through pits in the tracheids Vessel Elements -short and large -form vessels when aligned end to end Both tracheids and vessel elements are dead at functional maturity and their function is to move water Phloem cells 1. Sieve tube elements a. Alive at maturity b. Don’t have organelles or a nucleus c. Let sugar flow 2. Sieve plates a. End walls have pores that let fluid move between cells in the sieve tube 3. Companion cells a. One per sieve-tube element b. Have nucleus and ribosomes that function for the companion and sieve tube cells Parenchyma photosynthesizes and stores nutrients, therefore it does the majority of metabolic functions Cell growth Indeterminate growth- growth that happens during all of plant’s life Determinate growth- stop growing once an organ reaches a certain size, such as leaves Annuals- life cycle is complete within a year Biennials- complete life cycle within 2 seasons Perennials- can live for several years Meristems -embryonic tissue -indeterminate growth -can differentiate Apical meristems -tip of axillary buds, roots, and shoots Primary growth -vertical growth Secondary growth -grows in thickness in wood plants, which is caused by lateral meristems 2 lateral meristems 1. Vascular cambium a. Adds vascular tissue, secondary xylem and secondary phloem 2. Cork cambium a. Replaces epidermis with periderm b. Periderm makes it thicker and tougher Roots Root cap -dead -grows into the dirt protects the meristem tissue There are 3 zones 1. Zone of division 2. Zone of elongation 3. Zone of differentiation Lateral roots -growth happens at the peridermal layer -the vascular tissue follows the roots -the root will break through peridermal tissue Stems Monocots -lack pith and cortex -have ground tissue -vascular bundles are scattered Leaves Palisade mesophyll photosynthesis occurs here Bundle sheath covers the vascular tissue Spongy mesophyll has gaps that enable gas exchange to occur. Stoma the guard cells maintain a balance between moisture and CO2 Secondary growth -meristematic cells is 1 layer of the vascular cambium -develops from undifferentiated parenchyma cells -secondary xylem accumulates and has tracheids, vessel elements, and fibers -early wood increases flow of water in spring -late wood increases amount of cells used for support during late summer -in perennials, the vascular cambium is dormant Tree rings where late and early wood meet Heartwood -old layers of secondary zylem -doesn’t move water or minerals anymore -used for support Sapwood -moves material through xylem Second phloem -doesn’t accumulate, breaks off over time Morphogenesis homeotic genes change structure of plants Cellular differentiation -produce different proteins that enable cells to become different in their function in structure despite of their common genome Homeotic genes positional information Positional information -young cells aren’t dedicated to a certain function. Their function is determined by their final position Phase changes -developmental phase -juvenile phase to adult phase -phases occur in the shoot apical meristem -juvenile is defined by not being able to flower -hormones and gibberellic acids regulate phase changes Genetic control -vegetative growth to reproductive growth = flower formation -requires meristem identity genes to be turned on. Others need vernalization -environment and internal cues are responsible for triggering growth Organ identity genes -regulate floral patterns -MAD box genes Misplaced structures are due to Hox genes ABC flower development 4 genes responsible for forming floral organs A= sepals A+B= petals B+C= stamens C= carpel Turgid- the cell membrane is pushed against the cell wall When plants wilt, it’s caused by lack of water, because to water also provides structure for plants Permanent wilting point point of no return. The plant will not rebound Aquaporine -Transport proteins -In the cell membrane, and their function is let water through and restrict solutes coming in Rate of water movement is regulated by phosphorylation of aquaporine proteins. Transport control -compartmental structure -Plasma membrane regulates which molecules enter -vascular membrane regulates transport between cytosol and vacuole Water and sugars -The cytosol and cell wall are continuous -Symplast cytoplasmic continuum -Plasmodesmata cytoplasm of neighboring cells is connected by channels -Apoplast continuum of cell walls and extracellular spaces -Transmembrane route through apoplast and symplast route Routes Symplastic route via cytosol Apoplastic route via cell walls and extracellular spaces Long distance -Bulk flow movement of fluid driven by pressure -Water and solute move through tracheids and vessel elements of xhylem and sieve-tube elements of phloem Absorbing water -root tips where water and minerals are absorbed -root hairs increase surface area -water crosses the cortex via symplast or apoplast Endodermis -Inner layer in root cortex -Around the vascular cylinder -Last stop for passage of minerals to enter the vascular tissue Casparian strip -waxy -has an endodermal wall that doesn’t allow apoplastic transfer into the vascular cylinder Bulk flow is driven by negative pressure in the xylem Xylem sap bulk flow replaces water loss -sap is pulled by roots and pushed by leaves What causes root pressure? -During the night, the root cells put mineral ions into the vascular cylinder xylem and lowers water potential Root pressure -water flows in from the root cortex -Roots have greater pressure than leaves Guttation excess water forms as droplets on tips of leaves Positive root pressure -weak -slightly aids in bulk flow of xylem Negative leaf pressure -Results due to transpiration -the negative pressure pulls on water that’s in the xylem -water is then pulled into the leaf Hydrogen bonds link water together. Adhesion allows water to “stick” to surfaces, preventing gravity from pulling water back down Stomata -account for the majority of water loss, up to 95% -3 cues 1. Light increases the uptake of potassium 2. decrease of carbon dioxide in leaf 3. internal clock (circadian rhythm) How stomata open -potassium goes into cell and water flows in to close -potassium goes out of cell and water goes out Desert adaptations -reduced leaves= fewer stomates -CAM CAM -at night, the stomata open -carbon dioxide is stored as malmate -majority of CAM species are angiosperms, but can also be ferns, gymnosperms, and monocots Sugar source to sugar sink -sugar source leaves produce the majority of sugars used by the plant -sugar sink consumers of sugar, tend to be bulbs or tubers -The season also determines what is a sink and source. In the summer, leaves are sugar sources. But in the winter, the leaves die. Now storage organs are sugar sources Sugar movement -moves via sieve-tube elements -can move symplastic and apoplastic -needs a cotransporters Water gets pulled by companion cell and phloem Xylem negative pressure. Bulk flow Phloem positive pressure Phloem -electrical signaling occurs in the phloem -moves macromolecules and some RNA through plasmodesmata Water and Sugar Algal ancestors could get minerals and carbon dioxide from the water Xylem and phloem are important in evolutionary history because they enabled plants to grow tall to compete for sunlight, increase the area of dispersal, and allow them to live on land. This is because xylem and phloem allow minerals and nutrients to travel long distances. Leaf area index upper leaf surface/ surface area of land Light absorption can also be affected by leaf orientation Self-pruning photosynthesis decrease below the basal respiration, which is when leaves don’t get the minimum amount of light in order to carry out their function Leaf Orientation -Affects rate of photosynthesis -Affects rate of water loss Diaheliotropism follow the sun Paraheliotropism avoids sun to retain more water Roots and Shoots When plant cells absorb minerals, nutrients, and water, this is when transport starts Selective permeability what is allowed into and out of the cell Diffusion -does not require energy -passive movement Facilitated diffusion -moves solutes across a membrane -most of the time needs transport proteins to facilitate movement Both diffusion and facilitated diffusion are forms of passive transport Active transport -Carrier proteins -create a hydrogen ion concentration gradient = potential energy -membrane potential like voltage. It is the difference between the interior of a cell and outside fluid The transport of solutes is caused by the energy in the proton gradient and membrane potential Proton pump -causes membrane potential and the proton gradient Cotransport -transport protein that works in pairs to allow the diffusion of a solute and active transport of another solute. -this is how sucrose is taken in by plant cells Diffusion of water Osmosis -water moving down its potential gradient across a semi-permeable membrane -affected by pressure and concentration Water potential -measures solute concentration and pressure -determines the direction of water -water goes from high water potential to low water potential -measured in MPa megapascals -0 MPa at sea level, room temp, and if it’s pure water -Solute potential (s) number of dissolved molecules. Also called osmotic potential -Pressure potential (p) the pressure on a solution Water potential= P + S Soil and nutrition Fragile ecosystem -top layer gives water and nutrients to plants -Organisms that live in the soil. Plants, bacterial, Insects, fungi, and nematodes Soil stratification -layers known as horizons -topsoil uppermost layer Smallest molecule to largest Clay silt sand Topsoil has living and dead organism and minerals and humus Loams -combo of silt, sand, and clay -very productive for plant growth A horizon topsoil. Living and decaying things are here B horizon less weathered rock C horizon parent material, and partially broken rock Inorganic -cations (potassium, calcium, magnesium) adhere to anion -prevents leaching Cation exchange cations are displaced by other cations Root hairs have an affinity for negative ions Acid rain -increases the proton concentration in soils. -important cations are dislodges -rain leaches the important nutrients Nitrogen oxide -fossil fuels Sulfur dioxide -Burn coal. When comes into contact with water becomes sulfuric acid Soil conservation Agriculture impacts -decrease nutrients -increase erosion -strains water -soil compaction Ogalla Aquifer -formed during the Ice Age and by glaciers -Aquifers near coasts are becoming saline. Fresh water sits on top of salt water, but we’ve tapped into that resource too much Pivot irrigation -minerals in water don’t evaporate and land becomes salty Drip irrigation -use less water and a decrease in salt Australia -2.5 million hectares are salinized. Fertilization -replaces lost minerals -Commercial fertilization adds nitrogen, phosphorous and potassium -Organic fertilization is manure, fish meal and compost -Natural fertilization is letting fields go fallow and doing crop rotations Modern agriculture -monoculture -fertilizer and bacteria dominated Control erosion -wind and water erode away topsoil -loss of nutrients -contour plowing -Use windbreaks -terracing hillsides -no till Nutrients -elements needed in order for a plant to finish their life cycle Macronutrients 9 that plants need in large amounts Carbon, oxygen, hydrogen, phosphorous, sulfure, potassium, calcium, magnesium, nitrogen Micronutrients plants need thsese only in small amounts Iron, manganese, boron, zinc, nickel, copper Rhizosphere- soil bound to roots -high microbial activity -roots secrete sugars, amino and organic acids Co-evolutionary relationship between plants and bacteria Rhizobacteria -free living -function in the rhizosphere -have the ability to enter roots -stimulate plant growth by making hormones -protect roots from disease by making antibiotics -make nutrients available Inoculation of seeds with rhizobacteria increases crop yields Bacteria and the nitrogen cycle 1. Nitrogen is in the athmosphere 2. Nitrogen goes into nitrogen fixing bacteria and organic material goes into ammonifying bacteria 3. Both the nitrogen fixing bacteria and ammonifying bacteria produce NH3 4. H+ from the soil makes NH4 5. NH4 can be used by plants 6. Nitrifying bacteria take NH4 and convert it to NO3 7. Denitrifying bacteria take NO3 and put N2 back into the atmosphere Legume roots -nodules infected with bacteria -bacteroids are in root nodules -bacteria give N2 and get sugar from plant Reproduction of angiosperms -pollen tube fertilizes egg -2 sperm go into the ovule -2n zygote grows into an embryo -ovary walls mature into a fruit -seed coat comes from integument which comes from the sporophyte (grand parents) -sperm comes from the parental generation Microsporangium -microsporocyte is 2n -4 microspores after meiosis n Megasporangium -megasporocyte is 2n -meiosis 1 n megaspore -mitosis 3 antipodal, 2 polar nuclei, egg, 2 synergids 2 polar nuclei + sperm= 3n endosperm 1 egg + 1 sperm = 2n zygote Zygote divides and terminal end grows Basal cell orientates the growing embryo Plant sexuality -angiosperms can be sexual and/or asexual -sexual= genetically different -asexual= can result in a clone Fragmentation separations of a parent plant into parts that eventually develop into a plant Parent root system give rise to adventitious shoots Apomixis asexual reproduction of seeds from diploid or haploid cell Forms of apomixes Nonrecurrent haploid gametophyte leads to a haploid individual Recurrent meiosis is not completed Adventive embryo arises from integument Vegetative flower replaced by a bulb Vegetative reproduction -asexual -beneficial for a successful plant -clones vulnerable if there’s a change in environment
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'