BSCI 124 Final Study Guide: Ecology and Plant Ecology - Prof. Edgar Moctezuma, Study notes of Plant Taxonomy and Evolution

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BSCI 124 Final Study Guide Ecology: study of effects of the environment on living organisms Plant ecology: interaction among plants Ecological hierarchy: Organisms – Populations – Communities – Ecosystems – Biosphere Population: members of single species Habitat: location where population is found – It’s ADDRESS Niche: functional role of an organism Plant Community – different populations of plants living together Dominant Species – most influential (redwood forest) --- Control, structure, species Physical: light, wind, humidity Chemical: nutrients, pH Ecosystem – functional unit of study in environment Biotic – living organisms Level of food chain – Trophic Level – energy lost at each level Biomass and fungi decomposers Food web more realistic: interactions between several food chains Abiotic factors: non-living components: climate, light, soil Biogeochemical factors – carbon, water, nitrogen cycle Carbon cycle: Carbon dioxide enters through phosphorus – Photosynthesis Water cycle: enter atmosphere as vapor from land Nitrogen cycle: produced by bacteria in plant nodules Biosphere – areas of East where organisms are found Biomass – interactions among Earth’s biosphere Greenhouse Effect: global warming: Earth’s temp has increased 1 . F more expected Plant Succession – series of predictable changes over time in the kinds of plants growing in an area Climax community – relatively stable community at the end of succession 1. Equilibrium with environment 2. Permanent (until major change) 3. Varies depending on conditions Succession: Primary/Secondary Primary Succession – when plants become established on land completely devoid of soil and vegetation Forest habitats: Lichens – mosses and ferns – grasses – shrubs – trees Each stage prepares next invasion Primary species – First inhabitants – forms soil---- Essential Soil – provides nutrients to all plants (water and minerals) Characteristics – Parent material, soil texture (3 kinds: sand, silt, ___________), soil pH (best neutral/acidic), organic matter Secondary Succession – human intervention destroy existing vegetation. Takes place 5 to 10 times faster Abiotic factors: weather, temperature, humidity Mount St. Helens, Washington (1980 erupt) Biome – largest terrestrial divisions of the biosphere Distribution largely controlled by weather Temperature – Precipitation- Wind – Humidity – Light – Fire – Soil Type Terrestrial Biomes 1. Tundra 2. Boreal coniferous forests (taiga) 3. Temperature deciduous forests 4. Grasslands 5. Deserts 6. Chaparral 7. Tropical rain forests Tundra – land without trees – around Arctic Circle Climate- very cold and dry (very little precipitation) Short growing season (60-100) Soil: wet, shallow, permanently frozen (permafrost) Submerged Aquatic Vegetation: include the bay grasses, hydrophytes (aquatic plants that live underwater) – Does not get enough SUNLIGHT Hydrophytes have unique adaptations 1. Holes(lacunae) in there tissues – allow for gas exchange 2. Chloroplasts located in the epidermis of leaves 3. Strap-sharp leaves – constant water movement 4. Water pollination Ecological functions of SAV: stabilize the bottom(w/ rhizomes), lessen energy of wave energy, promote sedimentation – improves water quality, provide nursery for sea horses – fish- crabs – shrimp, provide food for ducks Marshes: tracts of wetlands with grasses - Salt marshes – closest to the sea, high in salt water - Brackish marshes – mixture of salt of fresh water - Fresh water marshes – mixing with salt water minimal Plant adaptations - Xerophytic: adaptations to low water stress, very drying to tissue - Get rid of salt that comes in - Spartina use salt glands to remove excess salt – PUMP OUT - Dilute, succulent leaves and stems Anchoring – thick rhizomes Anchoring soil – lacunae in roots Ecological roles of Marshes - Improve water quality - Trap sediment - Absorb nutrients and pollution - Stabilize sediments with salt - Provide food and habitat Biodiversity: variety and variability of life forms 10. Magnoliphyta (flowering plants) --- 245,000 species Concepts 1. Rivet pooper: each species important in their own way (lose a lot whole ecosystem fails) 2. Redundancy: only are critical to the survival of the ecosystem Evidence: crop production increases with biodiversity, full productivity can be reached with a few species Levels of diversity: Speciation – occurs when a population diverges from another to become a separate species Rates of speciation 1. Tropics and deserts: Rapid 2. Aquatic habitats: Low 3. Environmental stress: Higher Humans major cause of species loss Biodiversity provides humans with Economic benefits and aesthetic benefits Many potential useful species going extinct before they are known Conservation: critical to maintaining currently available biodiversity Critical habitat: area required to maintain the rest of the species Germplasm preservation: collecting seeds from wild and cultivated species Extinction: loss of a species from the biota, causing worldwide disappearance Extirpation: loss of species from a significant portion Endemic: species restricted to a defined area 99% of all organisms are extinct Background extinction – continuous low-level rate of species loss Mass extinction – large loss of species Causes: climate changes, geologic events (dramatic flooding, volcanic activity), Meteorites, Humans Atmosphere: a thin layer of gases that envelope the Earth Gases 1. Nitrogen 78% 2. Oxygen 21% 3. Argon .9% 4. Carbon Dioxide .03% Layers of atmosphere (4) 1. Thermosphere: layer beyond 90km – HOTTEST layer due to solar radiation 2. Mesosphere: reaches the coldest temperature 3. Stratosphere: jets fly here, has steady winds 4. Troposphere: layer closest to Earth’s surface – weather occurs on this level Fossil Fuels: organic substances found in underground deposits formed in previous geologic periods Coal (solid) and Oil and natural gas (liquid and gaseous) Fossil fuel particles 1. Sulfur dioxide: from burning coal 2. Carbon monoxide: about 10% comes from fires, cars 3. Nitrogen: from cars and power plants 4. Hydrocarbons: 80% from natural sources, but 20% from cars Acid Rain: acidic decomposition that occurs near or downwind of areas where there are major emission of sulfur dioxide and nitrogen oxides Carbon dioxide a trace gas but the amount has been increasing Why: burning of fossil fuels, deforestation (removing trees) Effects: air temp changes, expanding deserts, increase in tropical diseases, low species diversity Solutions: Kyoto Protocol, cut back on emissions Effects of high UV: Humans- higher skin cancer and cataracts, weak immune system Plants- crop damage, destroys chlorophyll so can’t photosynthesize Smog – haze caused by the action of solar UV radiation on atmosphere Causes: reduction of plant growth rates, animals have reduced visibility, eye irritations The Green Evolution: scientifically developed food crops that can produce high yields- Needs high water, fertilizers, and pesticides Environmental impact of agriculture 1. Declining genetic diversity 2. Soil erosion: loss of soil comes from tilling(plowing), topsoil is lost it contains nutrients Solutions: less plowing, more perennials, crop rotation 3. Soil Stalinization (because of irrigation salt builds up in the soil) 4. Desertification: expansion of desert at the expense of cropland Causes: overgrazing – livestock consuming more plants, cultivating crops, improper irrigation, deforestation