Biodiversity supports ecosystems provides food medicine resources keeps environments stable and is essential for human survival without BD ecosystems collapse Evolution by natural selection Darwin Wallace Explains why species exist why they are different how new species form over time Scientists organize life using a system created by carl Linnaeus each species gets a binomial two part name first word is the genus and second identifies the species within that genus Taxonomists or systematists specialists who describe organisms and classify them Genus small group Genera grouped into a family into orders into classes phyla kingdoms domains Three domains Bacteria Archaea and Eukarya Bacteria and Archaea is microscopic forms of life that evolved for years Chordata includes all vertebrates TOP characteristic of species is the ability of individuals to interbreed Number of species occurring in a particular area is species richness Phylogeny branching tree like family tree structure results in one species becoming two Abiotic non living Evolution The structure of biodiversity Populational Thinking Thinking about variation within a population and how it changes over time population groups of individuals of the same species living in the same area Two main parameters standard deviation and the mean Mean an estimate of the value of the typical individual in the population Standard Deviation Measure of variation Average distance from the mean Typologically They assign things to categories and expect them to fit into them Charles Darwin is famous for his theory of evolution by natural slection most well known naturalists of his time started exploring the world in the early 1830s Wallace Bates also made contributions Wallace developed the idea that geographic distributions of plants and animals are determined by the geological history of the areas they inhabit Bates developed the idea of mimicry that animals and plants evolve patterns to resemble other species to avoid being eaten Darwin had 2 major contributions Natural selection and branching pattern of evolution from a common ancestor NS is the primary mechanism of evolution Individuals within a population are variable Parents pass characteristics onto offspring Not all individuals can survive and reproduce resources are limited Some characteristics make individuals more likely to survive and reproduce Evolution by NS requires 1 Populations are variable in their characteristics or traits 2 Variation is heritable 3 Certain traits are associated with higher survival or reproduction Great diversity of life came about through a process of divergence through time Body size is probably correlated with lifespan in a natural environment The bigger the animal the lower risk of being eaten NS and other evolutionary processes tend to remove variation from populations This variation is necessary to produce evolutionary change Stabilizing Most common People with characteristics close to the mean are the most successful stays at mean population but becomes less variable Directional One end is more successful than other the population mean tends to shift in the direction of selection common response to a change in environment Disruptive close to the population mean do the worse those at extremes do the best diverge into two different groups produce two forms of life from 1 May not be very common Another way of producing divergence is geographic separation Single breed splits into two different geographic regions thus generating diversity Evidence for speciation Fossil record species on islands derived from continental forms islands referred to labs of speciation Second source of diversity Ecological interactions Ecology Factors influencing the distribution and abundance of organisms Or as the interactions between organisms and their environment Climate and other aspects of the environment are highly variable Two variables temperature rainfall Mediterranean Climates rainfall occurs during cool weather and is fairly gentle dry summers Arid climates the rainfalls during periods of hot weather usually violent storms Micro climate effect of local factors such as shade soil type and slope Can produce diverse forms of life Ecological Niche each type of organism is a species and each species has a particular set of environmental conditions in which it normally occurs Community species in a specific location or a more specific subset of organisms Mutualisms interactions in which both species benefit Competition interaction in which both species suffer a cost from the interaction Predation interaction in which one species benefits from the interaction and the other species suffers a cost Species interactions can lead to coevolution A producer is an organism that makes its own food through photosynthesis A decomposer is an organism that feeds on dead organic matter Primary consumer Feeds on producer Secondary consumer feeds on primary consumer Disturbance Ecological Succession new species come in after disturbance and community returns to the state before Similar climates similar habitats biomes High disturbance Low diversity Low disturbance low diversity Intermediate disturbance high diversity Biotic factors organisms of ecosystem abiotic factors non living parts of ecosystem Organisms in ecosystem need both matter and energy Matter in forms of nutrients remain permanently in ecosystems Producers bring energy into the ecosystem through photosynthesis and transfer carbon and water from the abiotic part of the ecosystem to the biotic The consumers feed on other forms of life The decomposers break down DOM Nitrogen is vital for life Proteins are composed of amino acids and each amino acids and each amino acid has at least one nitrogen atom Bio and agriculture Differences between Agriculture and other ecosystems 1 Simplicity the as has the crop species and the minimum number of other species required to keep it going 2 Inputs water and fertilizer are often added to AS and are generally not cycled within these systems to any significant extent 3 Removal crops are removed from ecosystem and consumed elsewhere In NS the selective force is the environment and in selective breeding the selective force is human choice of breeding Without a genetically diverse orginal stock it s difficult to continue to generate new strains as needed More genetically uniform more chances of new disease If identical crops will not survive 3 techniques for modifying organisms 1 Identifying
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