Presentation on theme: "Ecology: Human Impact & Conservation"— Presentation transcript:
1 Ecology: Human Impact & Conservation IB BiologyG3 & G4
2 Numbers of individuals Biological DiversityBiological Diversity: Evenness and RichnessRichness: the number of different organisms in a particular area (kinds of species)Evenness: how the quantity of each different organism compares to the others (abundance of kinds of species)Numbers of individualsFlower SpeciesSample 1Sample 2Daisy30020Dandelion33549Buttercup365931Total1000Is a community diverse if it is dominated by a single species? Why/why not?
3 Simpson Diversity Index A measure that takes into account richness and evennessFormula: D =Where:D = diversity indexN = total number of organisms in the ecosystemn = number of individuals of each speciesN (N-1)sum of n (n-1)
4 Simpson Diversity Index Example SpeciesNumber (n)n(n-1)Woodrush2Holly (seedlings)856Bramble1Yorkshire FogSedge36Total (N)1564Σ n(n-1)D = 15 (14)64D = 3.3What does this number represent? How can it be used?
5 Reasons for Conserving Biodiversity EconomicExamples: rainforest soils for crops; pharmaceuticals; ecotourismEcologicalLoss of diversity could collapse the ecosystem; diversity makes ecosystems less susceptible to invasive alien species; diversity of plant species buffers the effects of increasing greenhouse gassesEthical“We do not inherit the earth from our ancestors, we borrow it from our children” Native American ProverbAestheticNature’s beauty inspires art, gives us awe, and is connected to human cultures in countless ways
6 Biological ControlThe use of an organism (introduced) to control another organismRisks: introduced organism may not behave as expected (Cane Toads)Benefits: introduced organism may be the only control mechanism flexible enough to be effective against another invasive with no predatorsExamplesPurple loosestrife (invasive in US and Canada) – controlled by 2 species of beetles (Gallerucella)Red Invasive Fire Ants (RIFA) (invasive on many continents) – controlled by Phorid fliesred fire ants and phorid flies video on NG.com
7 BiomagnificationThe process by which chemical substances become more concentrated at each trophic level.[Increase]: 10 million times
8 CFCs and OzoneIn the atmosphere, CFCs (used in refrigerator coolants, propellants, and foam packaging) release chloride ions.The chloride ions react with ozone (O3) and produce ClO and oxygen gas (O2)The ClO molecules react with atoms of O to form more O2 and free up the ClIn this way the CFCs behave like a catalyst that doesn’t get used up and is free to destroy ozone for a centuryDepleted ozone layer permits more UV radiation through the atmosphereUV radiation causes:Skin cancer, DNA mutation, sunburn, cataracts, reduced biological productivity, and may be related to loss of amphibian biodiversity globally
9 Indicator Species AKA “the canary in the coal mine” Organisms sensitive to environmental conditionsExamples: Lichen (air pollutions like lead/mercury), macroinvertebrates (water quality)
10 http://www. people. virginia. edu/~sos-iwla/Stream-Study/Methods/Form Biotic Index
11 Biodiversity in a Nature Reserve Size of the ReserveSingle large or several small sites? Single large better because small sites = small populations (greater chance for extinctions from disease/lack of genetic diversity). Small sites also have more edges (see next). Some organisms have require large territories that can’t overlap.Edge EffectEcology at the edge of an ecosystem is different from the center. Edges can have more sunlight, more wind, less moisture, and fewer trees. Edge organisms may have more competition/fewer resources. Edges are more susceptible to invasive species.CorridorsSmaller, otherwise isolated habitats, connected by corridors allow organisms to travel between them. Problems include exposure in narrow corridors, invasives, and human/animal interactions around corridors.
12 Management in Conservation Areas Restoration: attempt to return the land to it’s natural state through various active management techniquesRecovery of threatened species: usually through habitat restoration (which helps all species ,declared threatened or not, who occupy the habitat)Removal of introduced species: active removal of invasives such as kudzu from the US southern states or leafy spurge in the US western statesLegal protection against development/pollution/huntingFunding and prioritizing: limited funding creates the need to make choices:Restore the habitats of all threatened species or just the ones that make the greatest overall impact?Remove all introduced species, or just invasives?
13 In Situ ConservationConservation of species within their natural habitat (where they belong), such as wildlife reserves, national parks, etc…Includes planning for improvement of biotic and abiotic factors of that habitatMaintaining habitat (space); defense of target species from predation; removal of invasives; maintaining large populations; maintaining genetic diversityAllows threatened species to adapt to environment with minimal interference from humans or invasivesTerrestrial reserves are common for in situ conservation, but marine aquatic reserves lag far behind
14 Ex Situ ConservationConservation of a species outside of their natural habitatNecessary if species is unsafe in the natural habitat, has a population too small to make a come-back, or if social/political/economic reasons make habitat protection impossibleExamples:Captive Breeding FacilitiesBotanical GardensSeed Banks
15 Captive BreedingZoos are the most common, most have large sections dedicated to captive breeding programs, animal husbandry experts, and money from tourismTechniquesArtificial insemination (when necessary)Embryo transfer to surrogate mothersCryogenicsHuman-raised young (when necessary)Pedigrees (to reduce inbreeding)Disadvantages:Captivity-bred organisms can spread disease to wild ones after re-introductionCaptivity-bred organisms lack the in situ learning and survival strategies
16 Botanical Gardens and Seed Banks 80,000 plant species kept in private gardens, arboretums and botanical gardens all over the world to protect and breed themFar easier to care for plants than to breed animalsProblem: wild relatives of commercial crops are under-represented. Genes from these plants could infuse longevity into traditionally inbred crop plants (i.e. bananas)Seed banks are keeping 10,000 to 20,000 plant species seeds in cold, dark conditions to prevent germination (for decades).