Abiotic/Biotic- Cannot live without each other- Organisms need Nutrientso Organic(carbs, fats, proteins)o Inorganic(minerals(calcium & sodium), water, oxygen)- “Troph” means “nourish”- External energy=Sun & Oceanic vents- All organisms need nutrients to survive; however, nutrients are unequally distributed due to abiotic factors- Plants/some bacteria/some protists obtain nutrients by photosynthesis (producers)o Also absorb nutrients- Bacteria/fungi/some protists obtain nutrients by:o Abosorbing nutrientso Recycling nutrients (decomposers)- Animals/some protists obtain nutrients by:o Ingesting nutrients (also known as consumers)- ALL transform nutrients in their own bodies.- 90% of nutrient energy lost to next organism; trophic levels limitedo Explains why there is a limit on trophic levels- Productivity varies in organisms by food source, temp. maintenance, etc.o How efficiently nutrients are converted into biomasso Producers-primaryo Herbivores/consumers-secondary- Nutrients unequally distributed-some areas have more external energy, nutrients, more productive, more trophic levels, more abundance- Organisms need more energy at the top of trophic levels- The ScienceDaily article about decline of large predators and apex consumers - Carrying capacity-the maximum population size- Random events CAN affect population growth- Density dependent factors(intraspecific competition) competition for resources, emigration, disease, predation, decrease in birth rate, varies year by year- Density independent (exponential) new habitat, recent die-off- Intra=within species; inter=between species- Niche-everything about the way you liveo Interspecific because of two or more populations wanting the same resources- Competitive Exclusion-two species want same resources, but one has traits that make it better able to get it, survive, and reproduce(more fit); less fit may go extinct locally- Niche differentiation-shifting of niche to avoid Competitive Exclusiono “Partitioning” resources by evolving traits (character displacement)o By shifting niche, the population is adapting to a new environment- Defensive adaptations-Physical, behavioral, chemical- Biotic interactions CAN be positive!- Organisms fit their niche, “not perfect”; trade-offs to the traits they haveEvolution and Natural Selection- Evolution is a change in a population over time- New species and fossils were discovered, so the idea of evolution was more accepted- Lamarck had said that individuals were changing due to the environment(WRONG)- Four steps to evolution by NS:o Overproductiono Struggleo Ones who survive are more fito Those that are more fit are more likely to survive and reproduce- Heritable variability codes genetically- Ex of struggleso Food competition (interspecific)o Droughto Food deprivation- More fit=more likely to survive and reproduce- NOT survival of the fittest; no reproduction=pointless- Traits do the “selecting” in natural selection- Adaptations=traits for fitness- Directional NS- trait change in one directiono Can shift back over time!o Reduces variation- Selective pressure-alters the behavior & fitness of living organisms; driving force of evolution- Peter & Rosemary Grant banded & measured every finch on Daphne Major (since 1973)o Beaks extremely variable- Descent with modification-passing on of traits from parent organisms to offspring; also known as heredity- Mutations are only minor on existing genes or regulations, which explains how descendants of species look very similar- Vestigial trait-a trait that used to be useful, but is not needed anymoreOther Important InfoBD- Interactions are a systemo Diverse systems tend to be healthier- BD is measured by species richness (ignores abundance)- Delineate species by:o Morphologyo Breedingo Genetics- Keystone species-organism that needs to be in a system, but does not benefit nor harm- Species equitability(evenness; relative abundance)- Diversity index(species diversity; richness & equitability)- Studying BD:o Size of areao Time periodo What organismso Abundance or rarity?DNA & Mutation- Instruction code for life- Structure of DNA is the same in every organism (evidence for common ancestry)o Double helixo Sugar-phosphate backboneo Nucleotide baseso Genes- DNA packaging:o Eukaryotes(daphnia, dogs) Linear chromosomes 23 pairs (diploid) of chromosomeso Prokaryotes(bacteria) Single piece of circular DNA; sometimes plasmids- Nucleotide base sequencemRNA(transcription)proteins(translation)traits- Ex of traits:o Size of beak, nose, tentacleso Color of flowers or hairo Protein that makes hemoglobin- Gene expression:o Constantly expressed(housekeeping)o Certain times(developmental)o Certain locations- Base sequence of genes are similar but not identical- Mutation-change in base sequence of a geneo Not always bado Code always the sameo Adds variationo Always random- Types of mutation:o Silent-no changes in gene(neutral)o Missense-only one amino acid is changed(good, bad, or neutral)o Frameshift-all amino acids change(bad)o Nonsense-inserts a stoop codon in the middle of protein(bad)- Alleles=gene variations- To affect YOU, mutation must:o Be in an expressed gene or regulatory geneo Cause a protein change- To affect YOUR CHILD:o Only if all of the above are true and the gene is passed ono If passed on, genetic diversity is added- Triggers:o Errors(spontaneous) Induced(UV radiation, cigarette smoke)- Genetic recombination between individuals adds to genetic diversityo Two types: Sexual recombination(meiosis)- DNA from parentone sex cell w/half of DNA- 3 sources of variation:o Crossing over(paired chromosomes exchange segments)o Independent assortment(shuffles up pairs so each sex cell gets new combos of maternal and paternal DNA)o Union of gametes(sperm fertilizes egg(random; adds variability & chance!)) Bacterial recombination(asexual organisms)- Mutations & recombination=populations of same species have lots of variability!- Genetics on humans vary based on location- Your genes are more similar to your family’s- Closely related species=more similar DNA- Law=principle that can be observed over and over- Theory=explains the law- Change in trait=change in