3/22-3/24 Bio 102 Notes
3/22-3/24 Bio 102 Notes Bio 102
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This 10 page Class Notes was uploaded by Alyssa Shriver on Monday March 28, 2016. The Class Notes belongs to Bio 102 at University of Tennessee - Knoxville taught by Dr. Jeremy Chandler in Spring 2016. Since its upload, it has received 27 views. For similar materials see Introduction to Biology in Biology at University of Tennessee - Knoxville.
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Date Created: 03/28/16
3/22/16 Lecture Community and Ecosystem Ecology Continued Ecosystem Biotic Trophic Structures o Primary consumers are called herbivores, which eat plants o Above the level of primary consumers are carnivores, which eat the consumers from the level below Secondary consumers eat primary consumers Tertiary consumers eat secondary consumers Quaternary consumers eat tertiary consumers Ecosystem o Complex, interwoven system of interacting components o Includes both community of living organisms and features of the nonliving environment o Biotic and abiotic parts o Dynamic systems A Hierarchy of Interactions o Many different factors can potentially affect an organism’s interaction with the environment Biotic factors are All of the organisms in the area and The living component of the environment Abiotic factors Are the environment’s nonliving component and Include chemical and physical factors, such as temperature, light, water, minerals, and air Environmental Variability o The abiotic factors in a habitat may vary From year to year Seasonally, or Over the course of a day Temperature o Temperature affects metabolism Few organisms can maintain a sufficiently active metabolism at temperatures close to 0 degrees C Temperatures above 45 degrees C destroy the enzymes of most organisms o Most organisms function best within a specific range of environmental temperatures Physiological Responses o Acclimation is Gradual, Reversible, and A physiological adjustment to an environmental change o The ability to acclimate is generally related to the range of environmental conditions a species naturally experiences o Among vertebrates, Birds and mammals can tolerate the greatest temperature extremes because they are endotherms, while Ectothermic reptiles can only tolerate a more limited range of temperatures Adjusting to Environmental Variability o Birds may adjust to cold by Migrating to warmer regions (a behavioral response), Growing heavier feathers (an anatomical response), or Fluffing up their feathers to trap more heat (a physiological response) Anatomical Responses o Many organisms respond to environmental challenges with some type of change in Body shape and Structure o Reversible change, such as a heavier fur coat in response to cold, is an example of acclimation Water o Water is essential to all life o For terrestrial organisms, the main water problem is drying out o Aquatic organisms Are surrounded by water and Face problems of water balance if their own solute concentration does not match that of their surroundings Inorganic Nutrients o The distribution and abundance of plants are often determined by the Availability of inorganic nutrients such as nitrogen and phosphorus and The structure, pH and nutrient content of the soil o In many aquatic ecosystems, the growth of algae, photosynthetic bacteria, and heterotrophic bacteria is often limited by levels of Nitrogen and Phosphorus Other Aquatic Factors o Aquatic but not terrestrial ecosystems are more limited by The levels of dissolved oxygen, Salinity, Currents, and Tides Other Terrestrial Factors o Terrestrial but not aquatic ecosystems are more limited by Wind, Storms, or Fire Fire Fighting o Forestry service adopted policy of suppression of all forest fires o Led to backlog of flammable tinder materials, which is largely thought to have led to the modern day mega wildfires we are experiencing o $ 3,500,000,000/ year to fight fires Disturbance o Disturbance disturbance alters the chemical or organismal components of an ecosystem o Disturbance is a normal part of some ecosystems Disturbances in Communities o Disturbances are episodes that damage biological communities, at least temporarily, by Destroying organisms and Altering the availability of resources such as mineral nutrients and water Disturbances in Communities and Ecosystems o Disturbances may cause The emergence of a previously unknown disease Opportunities for other organisms to grow Ecological Succession o Disturbances may cause a gradual replacement by other species in a process called ecological succession o Primary succession begins In a virtually lifeless area with no soil, In place such as The rubble left by a retreating glacier or Lava flows Ecological Succession o Secondary succession occurs where a disturbance has Destroyed an existing community but Left the soil intact o Examples of secondary succession are areas recovering from Floods or Fires Ecosystem Ecology o Energy flow Is the passage of energy through the components of the ecosystem Flows through and is ultimately lost o Chemical cycling Is the use and reuse of chemical elements such as carbon and nitrogen within the ecosystem Recycled within and between ecosystems o Each day, Earth receives about 10^19 kcal of solar energy. o Most is absorbed, scattered, or reflected by the atmosphere or surface of Earth Primary Production o The amount, or mass, of living organic material in an ecosystem is the biomass o The rate at which an ecosystem’s producers convert solar energy to the chemical energy stored in biomass Is primary production Yields about 165 billion tons of biomass per year o Different ecosystems vary considerably in their primary production Today’s Objectives o Explain how energy gets from the sun into a snake o Be able to interpret map range data and come up with hypotheses around factors that might influence populations o Compare and contrast adaptation vs. acclimation processes in organisms o Explain the limitations in aquatic vs. terrestrial biomes o Explain scenarios where disturbance could be good or bad for the functioning of an ecosystem o Explain the different levels of ecological succession o Explain the differences between energy flow and chemical cycling in an ecosystem 3/24/16 Lecture Biomes, Nutrient Cycles and a little Human Evolution Photosynthetic microorganisms contribute about 50% of Earth’s primary productivity Biomes o A biome is A major terrestrial or aquatic life zone, Characterized by Vegetation type in terrestrial biomes or The physical environment in aquatic biomes o Aquatic biomes Occupy roughly 75% of Earth’s surface and Are determined by their Salinity and Other physical factors o Freshwater biomes Have a salt concentration of less than 1% and Include lakes, streams, rivers, and wetlands o Marine biomes Typically have a salt concentration around 3% and Include oceans, intertidal zones, coral reefs, and estuaries Freshwater Biomes o Freshwater biomes Cover less than 1% of Earth, Contain a mere 0.01% of its water, Harbor about 6% of all described species Are used of Drinking water Crop irrigation Sanitation, and Industry Freshwater biomes fall into two broad groups: Standing water includes lakes and ponds Flowing water such as rivers and streams Aquatic Biome portioning of life o In aquatic biomes, the communities of plants, algae, and animals are distributed according to the Depth of water and Distance from shore Aquatic Life Zones o The photic zone, named because light is available for photosynthesis, includes The shallow water near shore and The upper layer of water away from shore o The aphotic zone Is deeper and Has light levels too low to support photosynthesis o The benthic realm is At the bottom of all aquatic biomes, Made up of sand and organic and inorganic sediments, and Occupied by communities of organisms that are collectively called benthos Roles of nutrients in aquatic biomes o The amount of phytoplankton growth aquatic environments is typically regulated by the nutrients available Nitrogen and Phosphorus Rivers and Streams o Rivers and streams Are bodies of water flowing in one direction and Generally support quite different communities of organisms than lakes and ponds o Source Streams Cold Clear Swift Lower Nutrients o Downstream Warmer Turbid Slow High Nutrients Biomes o Aquatic: marine o Aquatic: freshwater o Tropical forest o Temperature forest o Grassland o Desert o Taiga o Tundra Terrestrial Biomes o Terrestrial ecosystems are grouped into biomes primarily on the basis of their vegetation type o A climograph is a visual representation of the differences in Precipitation and Temperature ranges that characterize terrestrial biomes The effect of climate on biome distribution o Heated by the direct rays of the sun, air at the equator Rises, Then cools, forming clouds, and Drops rain o This largely explains why rain forests are concentrated in the tropics, the region from the Tropic of Cancer to the Tropic of Capricorn Chemical cycling in ecosystems o All life depends on recycling of chemicals o Nutrients acquired are ultimately released by a waste by living organisms o Death nutrients and chemicals that make up organisms are returned to the environment through decomposers Biogeochemical cycling o Biogeochemical cycles involve Biotic components and Abiotic components from an abiotic reservoir where a chemical accumulates or is stockpiled outside of living organisms o Biogeochemical cycles can be: Local or Global o Three important biogeochemical cycles are: Carbon Phosphorus and Nitrogen The Carbon Cycle o Carbon, the major ingredient of all organic molecules, Has an atmospheric reservoir and Cycles globally o The cycling of carbon between the biotic and abiotic worlds is accomplished mainly by the reciprocal metabolic processes of Photosynthesis and Cellular respiration The Phosphorus Cycle o Organisms require phosphorus as an ingredient of Nucleic acids, Phospholipids, and ATP o Phosphorus is also required as a mineral component of vertebrate bones and teeth o The phosphorus cycle does not have an atmospheric component The Nitrogen Cycle o Nitrogen is An ingredient of proteins and nucleic acids and Essential to the structure and functioning of all organisms o Nitrogen has two abiotic reservoirs The atmosphere and The soil o The process of nitrogen fixation converts gaseous N2 to nitrogen compounds that plants can assimilate o Most of the nitrogen available in natural ecosystems comes from biological fixation performed by two types of nitrogenfixing bacteria Some bacteria live symbiotically in the roots of certain species of plants, supplying their hosts with a direct source of usable nitrogen Freeliving nitrogenfixing bacteria in soil or water convert N2 to ammonia, which then picks up another H+ to becomes ammonium (NH4+) What is a virus? o A virus is a noncellular particle that must infect a host cell, where it reproduces It typically subverts the cell’s machinery and directs it to produce viral particles o Consist of nucleic acid (DNA or RNA) contained within a protective protein capsid o Viruses share some, but not all, characteristics of living organisms. o Viruses Possess genetic material in the form of nucleic acids wrapped in a protein coat, Are not cellular, and Cannot reproduce on their own Bacteriophages o Bacteriophages, or phages, are viruses that attack bacteria o Phages consist of a molecule of DNA, enclosed within an elaborate structure made of proteins o Phages have two reproductive cycles In the lytic cycles Many copies of the phage are produced within the bacterial cell, and Then the bacterium lyses (breaks open) In the lysogenic cycle, The phage DNA inserts into the bacterial chromosome and The bacterium reproduces normally, copying the phage at each cell division Today’s Objectives o Explain where the majority of primary productivity is derived in aquatic and terrestrial biomes o Explain how aquatic and terrestrial biomes are characterized o Explain the various zones we see in an ocean setting and how they interact in terms of energy flow and nutrient availability o Explain how by just looking at the picture of the Smokies today you could get a general idea of what expected rainfall in the environment might be like o Explain the 3 important nutrient cycles we discussed today and where their respective reservoirs are o Explain why a virus is non living but might be considered by some as living o Explain the lytic and lysogenic cycles in bacteriophages