BIOL 1720 Study Sheet for Exam 4 (Final) - Study Guide

# Study Sheet for Exam 4 (Final) ## Chapter 29: Resource acquisition by vascular plants - **A.** Photosynthesis and natural selection facilitated shoots turning into new adaptations. - **B.** Transports through the roots - **a.** Symplast: Cytosol of all living cells in a plant and the plasmo...

# Study Sheet for Exam 4 (Final) ## Chapter 29: Resource acquisition by vascular plants - **A.** Photosynthesis and natural selection facilitated shoots turning into new adaptations. - **B.** Transports through the roots - **a.** Symplast: Cytosol of all living cells in a plant and the plasmodesmata that connect them. - **b.** Apoplast: Consists of everything external to the plasma membrane of living cells. - Cell walls. - Extracellular spaces. - Interior of vessel elements and tracheids. - **C.** Three transport routes in xylem - **a.** The symplastic route, across one membrane and then cell-to-cell through the cytosol and plasmodesmata. - **b.** The apoplastic route, through cell walls and extracellular spaces. - **c.** The transmembrane route, in and out of adjacent cells through cell walls and plasma membranes. - **D.** MOVEMENT - **a.** Uses selective permeability. - **b.** Active transport (in phloem) - Use energy of proton gradient to utilize cotransport as part of active transport. - **c.** Passive transport (in xylem) - **d.** Osmosis, the diffusion of free water across a membrane. - **e.** Water potential predicts the direction of water flow during osmosis. - _Ψ_ is 0 mPA at sea level and 25C. - Unit of pressure is measured in megapascals. - Solute potential is osmotic potential and is directly tied to molarity (or negative) - Pressure potential (_Ψ_p) is physical pressure on a system (positive). - **f.** Protoplast is the living part of the cell, including the plasma membrane. - **g.** Turgor pressure is the pressure exerted by the protoplast against the cell wall. - Wilting is loss of turgor pressure in plants. - Reversible. - **h.** Long-distance transport occurs through bulk flow, the movement of a liquid in response to a pressure gradient. - Bulk flow occurs within the tracheids and vessel elements of the xylem and the sieve-tube elements of the phloem. - These are dead at physical maturity. - **E.** Nutrition in plants - **a.** Macronutrients - C, H, N, O, P, S, Ca++, K+, Mg++. - **b.** Micronutrients - Cl, Fe, Mn, B, Zn, Cu, Ni, Mo. - Chlorine, iron, manganese, boron, zinc, copper, nickel, and molybdenum. - **F.** Soils - 45% Mineral - 25% Air - 25% Water - 5% Organic Matter - **G.** Soil types - Silt - Sand - Clay - **H.** Best soils are LOAMs and mixtures of these three. - **I.** Note role of rhizobacteria (Nitrogen metabolism) - Nitrogen fixing (N2 gas to NH3 or NH4 in the soil) - Nitrifying bacteria oxidize ammonia (NH3) to nitrate (NO3¯). - Rhizobium bacteria form bacteroids, which are contained within the vesicles of the root cells inside the nodules. - **J.** Note role of mycorrhizal fungi (mineral uptake) - Host plant provides the fungus with a steady supply of sugar. - Fungus increases surface area for water uptake and provides phosphorous and other soil minerals to the plant. - Ectomycorrhizae forms a dense sheath (mantle) of mycelia over the surface of the root. - Arbuscular mycorrhizae extend fungal hyphae into the root without forming a mantle. - **K.** An epiphyte is a plant that grows on another plant, usually anchored to the branches or trunks of living trees. - Water and minerals from rain. - Host not harmed. - **L.** Parasitic plants absorb water, sugars, and minerals directly from their living hosts through specialized roots. - **M.** Transport of Water and Minerals into the Xylem (passive) - Apoplastic route, along cell walls and extracellular spaces. - Symplastic route, in the cytoplasm, moving between cells through plasmodesmata. - Transmembrane route, moving from cell to cell by crossing cell membranes and cell walls. - **N.** Casparian Strip - Made of Suberin. - Waxy material that blocks apoplastic flow of water and dissolved minerals in the stele of vascular cylinder. - **O.** Transport of xylem sap involves transpiration. - Loss of water vapor. - Evapotranspiration. - Transpirational pull is generated by the diffusion of water vapor out of leaves through the stomata. - Cohesion and adhesion play a role in the ascent of xylem sap as well. - **P.** Xerophytes are plants that have adaptations to arid climates. - Thick cuticle and multilayered epidermis. - Stomata recessed in crypts lined with trichomes. - Leaves reduced to spines or dropped for part of the year; photosynthesis occurs in stems. - Short life cycles completed during the rainy season. - Fleshy stems for water storage. - **Q.** Crassulacean acid metabolism (CAM) plants close stomata in the day but open them at night. - **R.** Movement through Phloem - Photosynthetic products are transported through the phloem by the process of translocation via sieve tube elements to sugar sinks. - Sugar source; organ that is a net producer of sugar, such as mature leaves. - Sugar sink: net consumer or storer of sugar, such as growing roots, fruits, or leaves. - **S.** Bulk flow (angiosperms) is by positive pressure/translocation. - Active transport. - Cells here are alive at functional maturity. ## Chapter 31: Plant response to internal and external signals - **A.** Plants respond to internal and external signals. - Light - Heat or cold stress. - Touch by wind or objects. - Drought or flooding. - Time (daylength and seasons). - Gravity. - Wounding by herbivores. - Infection by pathogens. - **B.** Tropism - Tropism includes all responses involving the curvature of a plant organ toward or away from a stimulus. - Phototropism describes the curvature of plant organs in response to light. - **C.** Plant hormones - Auxin (cell elongation; role of proton pumps and expansins) - Fruit production in greenhouse tomatoes. - Indolebutyric acid (IBA), a natural auxin, is used to induce growth of adventitious roots for vegetative propagation. - 2,4-dichlorophenoxyacetic acid (2,4-D),-- artificial herbicide. - Cytokinins (cell growth and division) - Work with auxin to stimulate cell division in undifferentiated cells that form callus tissue. - Role in apical dominance. - Gibberellins (stem elongation, fruit growth, and seed germination) - Stem elongation. - Sprayed on Thompson seedless grapes to make larger. - Role in breaking dormancy in seed germination. - Abscisic acid (drought hormone) - Effects of ABA include the promotion of seed dormancy and drought tolerance. - Inhibits germination. - Delays germination until environmental conditions are suitable. - Ethylene (gas produced by ripening fruit) - Released by stresses such as drought, flooding, damage, and infection. - Responsible for: - Response to mechanical stress. - Senescence. - Leaf abscission. - Fruit ripening. - Triple response: - Slowing of stem elongation, thickening of the stem, and horizontal growth until the stem has cleared the obstacle. - **D.** Senescence is programmed death of cells, organs, or the entire plant. - **E.** Photomorphogenesis - Morphological adaptations for growing in darkness, collectively called etiolation. - De-etiolation is a return to normal growth when exposed to light. - Plants detect not only presence of light but also its direction, intensity, and wavelength (color). - Red and blue light are most important. - Two major classes of photoreceptors: blue-light photoreceptors and phytochromes that absorb mostly red light. - Cryptochromes are involved in blue-light-induced inhibition of stem elongation during seedling emergence. - Phytochromes (red light) regulate many responses to light, including seed germination and shade avoidance. - There is interesting biochemical conversions of Pred and Pfar red. - Early research was with lettuce sees. - Biological clocks. - Flowering: - Plants that flower when a light period is shorter than a critical length are called short-day plants. - Plants that flower when a light period is longer than a critical length are called long-day plants. - Flowering in day-neutral plants is controlled by plant maturity, not photoperiod. - **F.** Mechanical stimuli - Thigmomorphogenesis refers to changes in form that result from mechanical disturbance. - Thigmotropism is directional growth in response to touch. - **G.** Stresses - Heat stress (heat shock proteins). - Flooding. - Salt stress. - Drought. - Cold stress (antifreeze compounds). - Environmental stresses (biotic or abiotic). - **H.** Responses to predators—thorns, chemicals. - **I.** Responses to pathogens - PAMP-triggered immunity: Pathogen-associated molecular patterns (PAMPS), must be recognized by the plant for this immune response to work. - Effector-triggered immunity: Some pathogens release effectors, pathogen-encoded proteins, that allow them to evade the PAMP-triggered immunity of the plant. - Effector-triggered immunity evolved as a response to protect plants from these pathogens. - Hypersensitive response, localized cell death near the infection site restricts spread of the pathogen (remember the oak limb that was brought to class last month). ## Chapter 40 Population ecology - **A.** Ecology is the scientific study of the interactions between organisms and the environment. - **B.** Organismal ecology considers how organism structure, physiology, and behavior meet environmental challenges. - **C.** Population ecology considers factors affecting population size and change over time. - Population: a group of individuals of the same species living in an area. - **D.** Community ecology examines how interactions between species affect community structure and organization. - Community: a group of populations of different species in an area. - **E.** Ecosystem ecology emphasizes energy flow and chemical cycling between organisms and the environment. - Ecosystem: community of organisms in an area and the physical factors with which they interact. - **F.** Landscape ecology focuses on factors controlling exchanges of energy, materials, and organisms across multiple ecosystems. - Landscape (or seascape): mosaic of connected ecosystems. - **G.** Global ecology examines how exchange of energy and materials at the regional scale influences the function and distribution of organisms across the biosphere. - Biosphere: global ecosystem—the sum of all ecosystems and landscapes on the planet. - **H.** The earth's climate determines distribution of terrestrial biomes. - Biotic: living factors. - Abiotic: non-living factors. - **I.** Global air circulation patterns - High temperatures in the tropics evaporate water from the surface and cause warm, wet air to rise. - As rising air expands and cools, it releases water as heavy precipitation over the tropics. - **J.** Seasons: due to tilt of earth. - Earth's tilted axis of rotation and its annual passage around the sun cause seasonality in middle to high latitudes. - Seasonal variation is smallest in the tropics and increases with latitude. - Day length, solar radiation, and temperature all cycle strongly with season. - **K.** Ocean currents - Ocean currents influence coastal climates by heating or cooling overlying air masses that pass across the land. - Large bodies of water are resistant to temperature fluctuation and can moderate the climate of nearby land. - Land heats up during the day causing overlying air to rise and pull cooler air from the water across the land. - At night, air rises over the now warmer water, and pulls cool air away from the land. - **L.** Vegetation absorbs excess sunlight than grasslands or deserts. - **M.** Terrestrial Biomes—know the characteristics of: - Tropical forest. - Savanna. - Desert. - Chaparral. - Temperate grassland. - Temperate broadleaf forest. - Northern coniferous forest. - High mountain. - Tundra. - Polar ice. - **N.** Endemic: a specific geographic area where a species is found like an island; contrast with pandemic which means on several continents. - **O.** What is ocean upwelling? Contrast with seasonal turnovers in lakes. - **P.** Know the aquatic biomes. - Pelagic realm (photic, aphotic, abyssal). - Intertidal neritic, and oceanic zone. - Coral reefs. - Lakes, wetlands. - **Q.** Aquatic biomes—very diverse and dynamic. - Zonation: - Photic zone is where light penetrates. - Aphotic zone, which both make up the pelagic zone. - Abyssal zone has bizarre creatures. - Benthic zone is ooze. - Role of turnover and nutrients in bodies of water in spring and fall. - Lakes' zonation have littoral and limnetic zone. - **R.** Density versus dispersion. - Density is the number of individuals per unit area or volume. - Dispersion is the pattern of spacing among individuals within the boundaries of the population. - **S.** Patterns of dispersion. - Clumped. - Random. - Uniform. - **T.** Demography. - Life table: - Mortality rate. - Birth rate. - Survivorship curves. - Type I: humans and elephants with die offs in the elderly. - Type II: equal deaths at all ages like birds. - Type III: mostly lose young or seedlings as in shrubs. - Reproductive table. - Look at age of first reproduction - Fecundity is reproductive capacity. - **U.** Do not expect to derive the equations. - Recognize logistic growth model equation. - Probably more realistic. - **V.** Population growth - Exponential growth—idealized unlimited environment - J-shaped curve. - Keep growing until they destroy food supply. - Idealized conditions have unlimited growth. - Logistic growth—population grows more slowly as it reaches its carrying capacity. - Curve is S shaped. - Accounts for role of limited resources on population - Carrying capacity limits growth. - Life history traits are products of natural selection. - Describe r selected and K- selected. - N is population size and K is carrying capacity. What is their role? - Population dynamics: - Idealized unlimited environment - **W.** Density dependent and density independent. - Density dependent: - Intrinsic. - Disease. - Territoriality. - Density independent does not change with higher population density. ## Chapter 41 Ecological communities - **A.** Community ecology is the study of interactions between species and factors that affect the number, type, and relative abundance of species in the community. - **B.** Community structure - Foundation species affect community structure by providing habitat and food for other organisms. - Competition, exploitation, and positive interactions between species affect community composition. - Disturbances caused by climate events, human activity, and other factors can remove organisms or alter resource availability. - **C.** Interactions between species can be mutually beneficial or harmful to one or both participants. - **D.** Interspecific interactions: - Interspecific interactions are grouped based on whether they have positive (+), negative (-), or no effect (0) on the survival and reproduction of interacting individuals. - Competition, predation, herbivory, parasitism, mutualism, and commensalism. - Individuals of different species compete for a resource that limits the survival and reproduction of each species. - Species do not compete for plentiful resources. - **E.** Competitive exclusion. - One species uses resources more efficiently and reproduces faster. - text example: paramecium - **F.** Ecological niche: - Set of biotic and abiotic resources used by an organism. - Role an organism plays in the environment. - Fundamental niche is the niche of a species that could potentially occupy based on the conditions it needs to grow and reproduce. - Realized niche is the limited niche that the species actually occupies when competing species are present. - **G.** Resource partitioning: - Differentiation of niches that enables this coexistence is called resource partitioning. - **H.** Character displacement: - When two competing species have geographically overlapping (sympatric) populations. - Geographically separate (allopatric) populations are morphologically similar and use similar resources. - **I** Exploitation: - One species benefits by feeding on another species. - Predation, herbivory, , and parasitism are examples. - **J.** Cryptic coloration is camouflage. - **K.** Bright warning coloration is aposematic coloration. - **L.** Parasitism: - Parasites that live within the body of their host are called endoparasites. - Parasites that live on the external surface of a host are ectoparasites. - **M.** Mimicry: - In Batesian mimicry, a palatable or harmless mimic species resembles a harmful or dangerous species (bees and robber flies). - Mullerian mimicry: two foul tasting organisms have similar color patterns. - **N.** Positive interactions: - Mutualism: both benefit. - Commensalism: one benefits; the other is neither hurt nor affected. - **O.** Species diversity - Species diversity has two components: species richness and relative abundance. - Species richness is the number of different species in the community. - Relative abundance is the proportion each species represents of all individuals in the community. - **P.** Shannon Diversity index. - **Q.** Trophic structures: - Food chain. - Food web. - **R.** Community dynamics: - Foundation species—essentially “sets up” a community (Prairie grasses, corals). - Keystone species-Not the most common but controls the community (Bison, sea stars). - Ecosystem engineers—beavers. - **S.** Top down and bottom-up regulation. - **T.** "Balance of nature: concept. - **U.** Disturbances - A storm, fire, or human activity, is an event that changes a community by removing organisms or altering resource availability. - The nonequilibrium model describes communities as constantly changing after disturbances. - High disturbance, low disturbance, or intermediate levels all exist. - **V.** Succession - Primary succession occurs on new areas where nothing existed or where a glacier recedes. - Secondary succession occurs where a disturbance has destroyed an ecosystem. - There are stages that occur as the area is reclaimed. - Weeds, annual plants, pine, and then deciduous trees. - Last community is a climax community (Not emphasized in the chapter). - **W.** The text describes stages when a glacier recedes and primary succession. - First liverworts, mosses form the pioneer community. - Then dryas. - Then alder. - Finally, Sitka spruce, western hemlock, and mountain hemlock. ## Chapter 42: Energy and Ecosystems - **A.** Energy flows through an ecosystem while energy cycles. - **B.** The law of conservation of mass states that matter cannot be created or destroyed. - **C.** Trophic levels—maybe 10% of the energy is transferred from one level to another. - Producers (autotrophs). - Primary consumers (herbivores). - Secondary consumers (carnivores). - Tertiary consumers (Carnivores). - **D.** Detritovores - Detritivores, or decomposers, are heterotrophs that get their energy from detritus, nonliving organic material. - **E.** Gross primary production. - Amount of energy converted to chemical energy in organic molecules in autotrophs per unit time. - Total primary production in an ecosystem. - **F.** Net primary production: - GP P minus energy used by primary producers for “autotrophic respiration. - NPP = GPP - R. - **G.** Limiting nutrients: - A limiting nutrient is the element that must be added for production to increase. - Nitrogen and phosphorous are common limiting nutrients in marine ecosystems. - **H.** Production efficiency - Production efficiency is the fraction of energy stored in food that is used for secondary production. - **I.** Energy pyramids: - A biomass pyramid represents the total dry mass of all organisms in each trophic level. - Most have a wide tier at the bottom representing primary producers and narrow sharply to the top-tier carnivores. - **J.** Biogeochemical cycles. - Nitrogen (reservoir k is N3 in the atmosphere). - Phosphorous (Reservoir are rocks). - Carbon (Reservoir are fossil fuels, organism, even sedimentary rocks). - Water. - **K.** Bioremediation. ## Chapter 43: Population Ecology and Global Change **A.** How to protect biodiversity. - Restore or preserve habitat. - Prevent and manage non-native species introductions. - Establish networks of protected areas. - Combat climate and other human-caused environmental change. - Harvest populations sustainably. - **B.** Biodiversity levels. - Genetic diversity. - Species diversity. - Ecosystem diversity. - **C.** Ecosystem services: - For example, purification of air and water. - Detoxification and decomposition of wastes. - Crop pollination, pest control, and soil preservation. - **D.** Threats to biodiversity. - Habitat loss. - Introduced species. - Overharvesting. - Global change. - **E.** Extinction vortex: - Inbreeding and genetic drift draw small populations down an extinction vortex into smaller and smaller size. - Inbreeding and genetic drift cause a loss of the genetic variation required for evolutionary responses to change. - Inbreeding further reduces fitness by increasing the frequency of homozygosity of harmful recessive alleles. - **F.** Minimum viable population - Minimum population size at which a species can survive. - **G.** Effective population size - Only look at breeding organisms. - Probably a more effective measure. - **H.** Landscape and ecosystem conservation - Fragmentation of ecosystem—look at size of fragments. - Edges are a different community. - Establishment of protected areas and zoned reserves. - **I.** Biological magnification—toxin build up in the food chain. - **J.** Toxins - Polychlorinated biphenyls. - Microplastics. - Toxins. - Pesticides like DDT. - **L.** Earth is a greenhouse planet. - **M.** Evidence for climate change: - Geological evidence, growth in knowledge. - Global warming has occurred—climate change is a better description. - Glaciers covered much of the US 100,00 years ago. - **O.** What is meant by a greenhouse planet? - **P.** What are greenhouse gases? - Carbon dioxide. - Methane. - Chlorofluorocarbons. - Nitrous oxide. - **Q.** Human population growth. - **R.** Paris accords - U. S. Senate will not ratify since it allows foreign diplomats to tax our citizens. - Most countries are meeting emission requirements. - **S.** Solution may be sustainable development.