Biology Keystone Remediation

Biology Keystone RemediationEvolutionBiogenesisBiogenesis states all living things come from other living things.Before the seventeenth century it was believed that living things could arise from nonliving thingsSpontaneous generation Redis ExperimentFrancesco Redi (1626-1697)Disproved that flies generated spontaneously from rotting meat.Observed the life cycle of flies.He noted that maggots appeared where flies had landed, they turned into pupas and then to flies.Experiment with open container with rotten meat (experimental) and closed container with rotten meat (control).

Spallanzanis ExperimentLazzaro Spallanzani (1729-1799)Designed an experiment using a microscope and broth to disprove spontaneous generation of microorganisms.Not everyone considered is experiment valid. They believed the heating was not the same for all samples.

imagePasteurs ExperimentLouis Pasteur (1822-1895)The Paris Academy of Science offered a prize to anyone who could end the spontaneous generation controversy.Pasteurs experiment wonCurve-necked flask was used. This allowed for air flow, but kept out solid particlesBroth was boiled and let stand No grow for up to a yearNeck was broken and growth occurred within a day.Spontaneous generation was disproved.

Earths HistoryEarth is approximately 4.6 billion years oldBased on studies of Earths surface and the use of radiometric dating.First Organic CompoundsSynthesized from the Earths early atmosphere along with a spark (lighting)Cell-Like StructuresMicrospheres-spherical in shape, composed of protein moleculesCoacervates-collection of droplets composed of lipids, amino acids and sugarsForm spontaneously in the laboratoryHave many of the same properties of life, expect for the hereditary characteristics.

The First CellsIt is believed that the first type of cells to evolve where anaerobic, heterotrophic prokaryotes (anaerobic live without oxygen, heterotrophic-consume to get food, prokaryotes single cell with no membrane bound organelles or nucleusFeed on the organic molecules from their surrounding environmentEventually these molecules would be gone and the first autotrophs evolved.

ChemosynthesisAutotroph that obtains energy from oxidizing inorganic compoundArchea unicellular organisms that strive in extremely harsh environmentsBelieved to be very similar to the first autrophs to evolve about 4 million years ago.Methanosarcina barkeriProduces methane during its metabolism

Photosynthetic AutotrophsAbout 3 million years ago the first photosynthetic organisms evolved.Similar to modern cyanobacteriaOxygen is a by product of photosynthesis and changed the make up of the Earths atmosphere The First EukaryotesFeatures of eukaryotes evolved from prokaryotesThe ER and nuclear envelope formed from the infolding of the plasma membrane of a prokaryoteLynn MargulisEndosymbiosis eukaryotic cells evolved from a mutually beneficial relationship between primitive eukaryote and the prokaryote it engulfed.Mitochondria and chloroplastsReplicate independently and contain some of their own genetic material similar to prokaryotes

Theory of EvolutionCharles Darwin (1823-1882) developed his theory while sailing around the world on the HMS BeagleGalapagos IslandsEvolution the development of new types of organisms from preexisting types of organisms over time; the change in the characteristics of a population over timeIdeas of Darwins TimeSpecies were permanent and unchangingJean Baptiste Lamarck (1744-1829)Inheritance of acquired characteristics individuals could acquire traits during their lifetime as a result of experience or behavior, then could pass on those traits to offspring.

Darwins IdeasOn the Origin of Species by Means of Natural Selection was published in 1859 a year after Darwin presented his research in LondonHis theory was supported by a large amount of evidenceHe used the phrase descent with modification to help explain evolutionSpecies descend by reproduction from preexisting speciesHe was the first to argue that all species originate this wayGalapagos Finches (Darwins Finches)-13 speciesNatural SelectionNatural Selection - Mechanisms of evolutionOverproduction of offspringMore offspring are produced than can surviveGenetic VariationIndividuals have different traitsStruggle to SurviveCompetition for resourcesDifferential ReproductionOrganisms with the best adaptation are most likely to survive and reproduce.Survival of the FittestEvidence to Support EvolutionThe Fossil RecordTypes and distribution of organisms on Earth have changed over time.Fossils of transitional species show evidence of descent with modification

Evidence to Support EvolutionBiogeographyDistribution of organisms, shows evidence of descent with modificationAnimals that are closely related, but adapted to different environments Animals that seem unrelated but have similar adaptations to similar environmentsEvidence to Support Evolution3. Anatomy Homologous structures- anatomical structures that occur in different species and that originated by heredity from a common ancestor Similar bone structure of forelimbs in humans, penguins, alligators, and bats

Evidence to Support Evolution3. AnatomyB. Analogous Structures-closely related functions by do not derive from the same ancestral structureWings of birds, bats, and mothsSimilar in function, but not in structure

Evidence to Support Evolution3. Anatomy C. Vestigial Structures-serve no function but that resemble structures with functional roles in related organismsHuman tailbone(coccyx)- four fused vertebrae that resemble the bones in an animals tailPelvic bones of modern whales and the human appendix

Evidence to Support Evolution4. EmbryologyStages of a vertebrate embryo development are very alikeIn early development this fades further into development

Evidence to Support Evolution5. Biological MoleculesModern scientists have shown that similarity in subunit sequences of RNA, DNA, and proteins indicates a common evolutionary history.Approximately 98% of our DNA is similar to the DNA of a chimpanzee.Evolution in ActionEvolution in ActionEvolution is a continuous process and can be observed, recorded and tested today. New species arise from environmental pressure and interactions with other species including humans.Convergent EvolutionConvergent evolution- process by which different species evolve similar traits.They live in similar ecosystems and have similar pressures.Similar but Separate while they may look similar their evolution occurred independently of one another.Bird and bat wings.

Divergent EvolutionDivergent Evolution- process by which descendants of a single ancestor diversify into species that fit different parts of the environment.Anole lizards twig-dwelling and trunk-dwelling

Sometimes, a new population in a new environment, such as an island, will undergo divergent evolution until the population fills many parts of the environment.This pattern is known as adaptive radiationDarwins finches.Artificial SelectionArtificial selection when a human breeder chooses individuals that will parent the next generation.DogsCoevolutionCoevolution when two or more species have evolved adaptation to each others influenceTogether, but DifferentAcacia tree and acacia antPopulation GeneticsGenetic EquilibriumPopulation biologists study many different traits in populations, such as size and color.Traits vary and can be mapped along a bell curve, which shows that most individuals have average traits, whereas a few individuals have extreme traits.Variation in genotype arise by mutation, recombination, and the random fusion of gametes.The total genetic information available in a population is called the gene poolGenetic EquilibriumAllele frequencies in the gene pool do not change unless acted upon by certain forces.The principle of Hardy-Weinberg genetic equilibrium is a theoretical model of population in which no evolution occurs and the gene pool of the population is stableGenotype frequencies in a population tend to remain the same from generation to generation unless acted on by outside influences.Disruption of Genetic EquilibriumEvolution can take place when a population is not in a state of genetic equilibrium. Thus, evolution may take place when populations are subject to genetic mutations, gene flow, genetic drift, nonrandom mating, or natural selection.Emigration and immigration cause gene flow between populations and can thus affect gene frequencies.Genetic drift is a change in allele frequencies due to random events. Genetic drift operates most strongly in small populations.Disruption of Genetic EquilibriumMating in nonrandom whenever individuals may choose partners. Sexual selection occurs when certain traits increase an individuals success at mating. Sexual selection explains the development of traits that improve reproductive success but may harm the individual.Natural selection can influence evolution in one of three general patterns.Stabilizing selection favors the formation of average traits.Disruptive selection favors the extreme traits rather than the average traits.Directional selection favors the formation of more-extreme traits.Formation of SpeciesAccording to the biological species concept, a species is a population of organisms that can successfully interbreed but cannot breed with other groups. (must produce fertile offspring)Geographic isolation results from the separation of population subgroups by geographic barriers. Geographic isolation may lead to allopatric speciation.Two closely related squirrels found on opposite sides of the Grand Canyon.Formation of SpeciesReproductive isolation results from the separation of population subgroups by barriers to successful breeding. Reproductive isolation may lead to sympatric speciation.Competing individuals within a population could gain an adaptive advantage by using slightly different niches. Which could lead to the groups becoming reproductively isolated.Darwins finches.

Formation of SpeciesIn the gradual model of speciation, species undergo small changes at a constant rate. In the punctuated equilibrium model, new species arise abruptly, differ greatly from their ancestors, and then change little over long periods.