Ecosystems & BiodiversityBBAEV 10201
Structure of BiosphereHierarchySpecies reproductive groupPopulation members of a single species that live in a given areaCommunity assemblage of interacting species in a given areaBiome a region with a characteristic plant community (e.g. rainforest, desert)Ecosystem a community of animals, plants, microbes, etc. together with the physical environment that supports it
Main Ecosystems:DesertRainforestOceanTaigaTundraChaparralGrasslandTemperate Forest
Green: Grassland Purple: Taiga Orange: Tundra Black: Temperate Forest Yellow: Desert Brown: Chaparral White: OceanGeography, weather, climate and geologic factors influences interactions within an ecosystem.
Organisms of EcosystemsAbiotic : Nonliving physical factors of an environment. It includes water, oxygen, temperature, amount of sunlight and water pressure etc.Biotoic: Living physical factors of an environment. Examples: Parasitism, disease and predation.
YOU TRY!!!List three more examples of Abiotic & Biotic Factors:
Second Law of ThermodynamicsThere is a tendency for numbers and quantities of biomass and energy to decrease along food chains.
The pyramids become smaller at the top because around 90% of the energy is lost between each level and only 10% is available in the body of the organism for transfer to the next level.
Ecosystem: Trophic levels
Pyramid of biomassBio=life Mass=weightBio + Mass = Weight of living things within an ecosystem.
The Trophic Pyramid: A Model of Consumption
Water cycle: More of physical process than chemical
Carbon cycle: biogeochemical process
Recent studies indicate that human activities have approximately doubled the worldwide supply of fixed nitrogen, due to the use of fertilizers, cultivation of legumes, and burning.Possible outcomeincrease nitrogen oxides in the atmosphereContribute to atmospheric warmingDepletion of ozoneAcid rain.
Accelerated pollution of lakes.Human intrusion has disrupted freshwater ecosystems by what is called cultural eutrophication.Sewage and factory wastes, runoff of animal wastes from pastures and stockyards have overloaded many freshwater streams and lakes with nitrogen.This can eliminate fish species because it is difficult for them to live in these new conditions.
Biological and geologic processes move nutrients between organic and inorganic compartments
Human activity intrudes in nutrient cycles by removing nutrients from one part of the biosphere and then adding them to another.Agricultural effects of nutrient cycling.Human population disrupts chemical cycles
In agricultural ecosystems, a large amount of nutrients are removed from the area in the crop biomass.After awhile, the natural store of nutrients can become exhausted.
The rates at which nutrients cycle function in ecosystems are extremely variable as a result of variable rates of decomposition.Decomposition can take up to 50 years in the tundra, while in the tropical forest, it can occur much faster.Contents of nutrients in the soil of different ecosystems vary also, depending on the rate of absorption by the plants.Decomposition rates largely determine the rates of nutrient cycling
Nutrient cycling is strongly regulated by vegetation.
Measurements (Co2 & Temp) in 1958 read 316 ppm and increased to 370 ppm today
Life on earth is protected from the damaging affects of ultraviolet radiation (UV) by a layer of O3, or ozone.Studies suggest that the ozone layer has been gradually thinning since 1975.Human activities deplete atmospheric ozone
Probable Reasons for destruction of ozone layer:Accumulation of chlorofluorocarbons, chemicals used in refrigeration and aerosol cans, and in certain manufacturing processes.Increased levels of UV radiation that reach the surface of the Earth. This radiation has been linked to skin cancer and cataracts.The impact of human activity on the ozone layer is one more example of how much we are able to disrupt ecosystems and the entire biosphere.
The burning of fossil fuels releases sulfur oxides and nitrogen that react with water in the atmosphere to produce sulfuric and nitric acids.Burning fossil fuel: Cause of acid precipitation
Humans produce many toxic chemicals that are dumped into ecosystems.These substances are ingested and metabolized by the organisms in the ecosystems and can accumulate in the fatty tissues of animals.These toxins become more concentrated in successive trophic levels of a food web, a process called biological magnification.Toxins concentration in successive trophic levels of food webs
DDT is a colourless, crystalline, tasteless and almost odorless organochloride known for its insecticidal properties
BalanceEcosystem will fail if it do not remain in balance. No community can carry more organisms than its food, water and shelter can accommodate.
Four Scientific Principles of Sustainability
How do they stay balanced?AdaptationMigrationExtinctionGive examples on each of the above?Provide your thought on ways to balance the ecosystem in the current scenario?
Why Is It Important?The biodiversity found in genes, species, ecosystems and ecosystem processes is vital to sustaining life on earth.
Natural Capital: Major Components of the Earths Biodiversity
Biodiversity over time - geologicNatural changes due to new species evolving and becoming extinctExtinction events cleans the slateNatural extinction 90% of species ever alive are extinct now
Genetic Makeup of a PopulationPopulations evolve by becoming genetically differentGenetic variations is the First step in biological evolutionOccurs through mutations in reproductive cellsMutations in other cells can happen , but only reproductive cell mutations are passed onSometimes a mutation can result in a new genetic trait that gives it a better chance to survive, sometimes not.
Try this Can a fish species willfully grow limbs and fingers if they are needed to crawl out of the water onto dry land?
Individuals in Populations with Beneficial Genetic TraitsNatural selection: Second step in biological evolutionAdaptation may lead to differential reproductionGenetic resistance in bacteria, cockroachesWhen environmental conditions change, populationsAdaptMigrateBecome extinct
Three Common Myths about Evolution through Natural SelectionSurvival of the fittest is not survival of the strongest Organisms do not develop traits out of need or wantNo grand plan of nature for perfect adaptation
There is a grandeur to this view of life (evolution) While this planet has gone cycling on
Endless forms most beautiful and wonderful have been and are being evolved
Charles DarwinCan you draw similes of evolution to Corporates/ organisations?
Geologic Processes Affect Natural SelectionTectonic plates affect evolution and the location of life on earthLocation of continents and oceansSpecies physically move, or adapt, or form new species through natural selectionTectonic actions: Earthquakes, Volcanic eruptions can have profound effects on natural selectionPollutionChange in ecosystem
Climate Change and Catastrophes Affect Natural SelectionIce ages followed by warming temperaturesDemise of the giants (Sloth, Saber tooth tigers)
Collisions between the earth and large asteroids New speciesExtinction
Changes in Ice Coverage in the Northern Hemisphere During the last 18,000 Years
Science Focus: Earth Is Just Right for Life to ThriveCertain temperature range (closeness to sun)
Dependence on water
Rotation on its axis (how fast or slow we spin)
Revolution around the sun (changes in season)
Enough gravitational mass (to hold on to the atmos)
What does Evolution mean to you?Evidence?
The Fossil Record Tells Much of the Story of EvolutionFossilsPhysical evidence of ancient organismsBones, casts, tracksSome reveal what their internal structures looked like, some their actions
Have all fossils been discovered?
Fossilized Skeleton of an Herbivore that walked the Earth
QuestionsQ1) What is the connection between the environment and evolution?
Q2) Will humans evolve to a point where we can survive in space without a spacesuit or any protective device? Why or Why not?
Q3) how does pollution effect evolution?
How Do Speciation, Extinction, and Human Activities Affect Biodiversity?As environmental conditions change, the balance between formation of new species and extinction of existing species determines the earths biodiversity. Human activities can decrease biodiversity by causing the premature extinction of species and by destroying or degrading habitats needed for the development of new species.
EvolutionThrough geographic isolationGroups of same species become physically isolatedMigration, physical barriers (volcanoes)Through reproductive isolationMutation and change by natural selection occur in isolated geographic populations long enough New species when interbreeding produces only sterile offspring
Geographic Isolation Can Lead to Reproductive Isolation
Science Focus: Humans Have Two Ways to Change the Genetic Traits of PopulationsArtificial selectionGenetic engineering, gene splicingConsiderEthicsMoralsPrivacy issuesHarmful effects
Genetically Engineered Mice