Transcript Biome
CHAPTER 52 INTRODUCTION . Ecology Overview Ecology is going to have a STRONG emphasis on how systems interact. You do not have to memorize any biomes in particular, but you must make connections from the molecular level (macromolecules) to entire biomes Ex: How can a change in pH in soil have an impact on an ecosystem. How is free energy measured? Overview: Energy TRANSFER • Cells • miniature chemical factories where thousands of reactions occur extract energy and uses it for work Some organisms convert energy to light • Bioluminescence (fungus, squid) Metabolism: transforms matter & energy, metabolism: total of all the chemical reactions in an organism’s body metabolic pathways begin with one molecule and ends with a product • each step catalyzed by specific enzyme Enzyme 1 A Enzyme 2 B Reaction 1 Starting molecule Enzyme 3 C Reaction 2 D Reaction 3 Product The First Law of Thermodynamics energy of the universe is constant • • conservation of energy energy can be transferred & transformed, but not created or destroyed Chemical energy The Second Law of Thermodynamics in transformation, some energy is unusable, and is often lost as heat • energy transfer or transformation increases entropy (disorder) of the universe Heat evolution of more complex organisms does not violate the second law of thermodynamics entropy (disorder) may decrease in an organism, but the universe’s total entropy increases Free Energy: ΔG = ΔH- TΔS Free energy = enthalpy (total energy) change - temperature x entropy change - ΔG: spontaneous • exergonic: cell respiration + ΔG: energy needed • endergonic: photosynthesis ΔG = ΔGfinal – ΔGinitial • If negative ΔG, spontaneous since less free energy exists in the products! reaching equilibrium means death, no work being done REVIEW Light energy Sunlight - ultimate energy source ECOSYSTEM Photosynthesis converts sunlight to glucose in chloroplasts; autotrophs CO + H O Cellular Respiration converts glucose to ATP in the mitochondria; autotrophs & heterotrophs 2 Photosynthesis in chloroplasts 2 Cellular respiration in mitochondria ATP powers most cellular work Heat energy Organic molecules + O2 Electrons carried via NADH and FADH2 Electrons carried via NADH Glycolysis Glucose Pyruvate CYTOSOL Pyruvate oxidation Acetyl CoA Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis MITOCHONDRION ATP ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation Cell Respiration Overview C6H12O6 + 6O2 6CO2 + 6H2O + ATP Cytosol Mitochondrial matrix Inner Mitochondrial Membrane 2 ATP 2 ATP 32 ATP Chemiosmosis couples the electron transport chain to ATP synthesis Chemiosmosis Ubiquinone & Cytochrome proteins carry e- through ETC, while proton pumps pump H+ from matrix to intermembrane space + H ions create gradient + H ions pass back through the enzyme ATP synthase into matrix and ATP is made ETC animation Fate of pyruvate determined by O2 Glucose CYTOSOL O2 present: • Pyruvate enters aerobic pathway: Kreb’s, ETC Pyruvate No O2 present Fermentation O2 present Cellular respiration O2 absent: • Pyruvate enters anaerobic pathway: alcohol fermentation or lactic acid fermentation MITOCHONDRION Ethanol or lactate Acetyl CoA Citric acid cycle Aerobic respiration, Anaerobic respiration, Fermentation Anaerobic Respiration Aerobic Respiration O2 Mitochondria e acceptor is O2 ~36-38 ATP (depends on amount of O2 available to the cell) No O2 Cytosol ETC has alternative e- acceptors ATP production variable Fermentation • • • • No O2 Cytosol e- acceptors are ethanol or lactate 2 ATP PHOTOSYNTHESIS: 1. Chloroplast structure Leaf Mesophyll Mesophyll cells Stomata – pores in leaf Granum (Grana) Stacks of thylakoids Stroma – fluid filled space Lumen – Inside thylakoids Thylakoid – individual membranes w/ folds for increased surface area Chlorophyll – pigment that reflects green light Chloroplast 5 µm Outer membrane Thylakoid Stroma Granum Intermembrane space Thylakoid space Inner membrane 1 µm 2. Pigments in leaves Chlorophyll a – primary pigment absorbs violet, blue and red Accessory Pigments – assist chlorophyll a in capturing light energy Chlorophyll b – absorbs blue and orange Carotenoids – absorbs blues 3. Photosynthesis Overview Light energy chemical energy for food 6 CO2 + 6 H2O + Light Energy C6H12O6 + 6 O2 2 steps 1. Light Reactions Occurs in Thylakoid membrane photo 2. Calvin Cycle – Light independent reaction or dark reactions Occurs in the stroma synthesis H2O CO2 Light NADP ADP + P CALVIN CYCLE LIGHT REACTIONS ATP NADPH Chloroplast Figure 10.5 O2 [CH2O] (sugar) Light Reactions Light Reactions 3. Water is split into oxygen Water is used to supply the electrons that were previously passed on in the electron transport chain. Chemiosmosis: The process in which energy stored in the form of a hydrogen ion gradient across a membrane is used to do cellular work. Calvin Cycle – Light independent reactions Occurs in the Stroma 1. Carbon from CO2 is used through a series of reactions to create G3P A sugar molecule used to create glucose 2. Uses ATP and NADPH to make sugar. Alternative Pathways Hot dry climates Conserve H2O Problem – closing stomata (stoma) to conserve water loss also cuts off CO2 which limits sugar production Sends the plant into photorespiration C4 Plants Sugar cane, corn, and some grasses Contains another enzyme in addition to rubisco- ONLY binds CO2 (not O2) making photosynthesis more efficient. Bundle sheath cells Minimizes photorespiration C4 vs. CAM Plants Pineapple Sugarcane C4 Mesophyll Cell Organic acid Bundlesheath cell (a) Spatial separation of steps. In C4 plants, carbon fixation and the Calvin cycle occur in different types of cells. CALVIN CYCLE Sugar CAM CO2 CO2 1 CO2 incorporated Organic acid into four-carbon organic acids (carbon fixation) 2 Organic acids release CO2 to Calvin cycle CALVIN CYCLE Sugar Night Day (b) Temporal separation of steps. In CAM plants, carbon fixation and the Calvin cycle occur in the same cells at different times. ECOLOGY, CH 52: You Must Know The role of abiotic factors in the formation of biomes. How biotic and abiotic factors affect the distribution of biomes. How changes in these factors may alter ecosystems Ecology: study of the interactions between organisms and the environment The ecological study of species involves biotic and abiotic influences. Biotic = living (organisms: behaviors & interactions between organisms) Abiotic = nonliving (temp, water, salinity, sunlight, soil) Levels of Organization Biosphere Biome Ecosystem Community Population Organism BBECPO Heirarchy Organisms- one living individual Population: group of individuals of same species living in a particular geographic area Community: group of populations of different species in an area Ecosystem: community of organisms + physical factors Biome: group of ecosystems that have the same climate and similar dominant communities (rain forest , etc.) BECPO BIOSPHERE portion of planet in which all life exists (includes land, water, atmosphere) Extends from: 8 km above the Earth’s surface to 11 km below the ocean’s surface BIOME • the world’s ecosystems classified according to dominant vegetation & rainfall Biomes Aquatic • Marine • • • • Intertidal zones Oceanic Pelagic Coral reefs Marine benthic zone • Freshwater • • • • Lakes Wetlands Streams and rivers Estuaries Terrestrial Tropical Desert Savanna Chaparral Grassland Coniferous forest (taiga) • Broadleaf forest (deciduous) • Tundra (arctic) • • • • • • ECOSYSTEM All the organisms in a community plus abiotic factors ecosystems are transformers of energy & processors of matter Ecosystems are self-sustaining what is needed? capture energy transfer energy cycle nutrients COMMUNITY • All the organisms that inhabit an area POPULATION individuals of the same species living in an area. capable of interbreeding and producing fertile offspring) Biogeographic Realms Organism’s Habitat habitat: place where an organism lives dispersal: movement of individuals from areas of high population density (or their area of origin) • disruption of existing communities and ecosystems usually occurs Organism’s Tolerance tolerance: range of conditions an organism can withstand acclimation: changing in response to environmental factors Responses to Change in Biotic & Abiotic Environment Migration Hibernation / Dormancy Conformers: change with the environments Regulators: maintain homeostasis regardless of external environment Organism’s Niche Niche: organism’s role in the environment • includes ALL biotic & abiotic factors an organism needs or uses fundamental niche: range or resources the organism can potentially use realized niche: resources the organism actually uses • if niches overlap competition for resources • Natural Selection Climate: long-term prevailing weather conditions in a particular area Climate = temperature + precipitation + sunlight + wind Climate patterns described on 2 scales: macroclimate or microclimate. Macro: at global, regional or local level Micro: small-scale environmental variation (eg. under a log) Climate change: some species may not survive shifting ranges Climate and elevation determine biomes Global Climate Patterns: Sunlight intensity Global Climate Patterns: Air Circulation & Precipitation Patterns Global Climate Patterns: Ocean Currents Global Climate Patterns: Mountains affect rainfall What is the rain shadow effect? Biomes: major types of ecosystems that occupy very broad geographic regions Climate and elevation determine biomes Figure 34.12 Climograph: plot of temperature & precipitation in a particular region Tropical Rain Forest Desert Savanna Chaparral Temperate Grassland Northern Coniferous Forest Temperate Broadleaf Forest Tundra Lakes Wetlands Streams & Rivers Estuaries Intertidal Zones Oceanic Pelagic Zone (Open Water) Coral Reefs Marine Benthic Zone In your notebook copy: Biogeochemical Cycle Definition: CHNOPS – Why is each needed? Be Specific! C (4) H (2) O (2) N (2) P (3) S (1) Nutrients vs. Energy Biosphere Cycles – For Each Cycle Reservoir (Stored) Plants get it? Animals get it? Returned to Reservoir ECOLOGY PROJECT Get in groups of 4 (no more) and begin researching biome. YOU MUST by today have a biome selected (specific name of area you’re studying) and have questions answered for part 1 Use the pogil diagrams to aid in this process. For example, if you’re researching a tundra, google “nitrifying bacteria in tundra” to get bacteria name