General Science Fact An observation that has been repeatedly confirmed Theory An explanation for broad patterns in nature that has been tested many times and is well substantiated Hypothesis Fact or Theory Law A description generalization about how some aspect of the natural world behaves under stated conditions Fact Theory or Law Hypothesis A possible explanation for some natural phenomenon Theory Hypothesis or Fact What are three key aspects to designing an experiment control group s constant conditions replication Gause Paramecium growing in the same petri dish Species with identical niches cannot coexist Connell Barnacle species Chthamalus vs Semibalanus competing Semibalanus is competitively excluding the Chthamalus from growing in low intertidal zones Krebs Hare and Lynx experiment enclosure vs extra food Keep out lynx had most effect Population keeping out lynx and extra food had the greatest survival Redi s experiment Meat in the jar Hypothesis Maggots come from flies Conclusion Maggots come from flies hypothesis is supported Pasteur Boiled nutrient broths v non boiled broths Hypothesis spontaneous generation and all cells from cells Results straight neck flask had microbes and swan neck flask was clear Conclusion Hypothesis supported that cells come from existing cells Testing Ideas is central to the process of science Evolution is a property of Populations not individuals Ecology 3 domains of organisms Eukaryota Bacteria Archaea What are the 3 factors that affect where a species is found 1 Dispersal ability 2 Evolutionary history 3 Biotic and Abiotic factors Ecologists strive to understand the factors that determine the Distribution and abundance of organisms Community A group of species living and interacting in an area Constitutive Defenses Always there Inducible Defenses Temporarily increase as protection Rhizobium bacteria mutualism live in plant nodules and fix soil nitrogen Mycorrhizal fungi mutualism Live on plant roots and expand root surface area Parisitoidism When a parasite lays eggs in a host and the offspring consume the host Omnivory Consuming more than one trophic level Keystone Species Even if there aren t many of them its super valuable in the composition of the community structure Foundation Dominant Species Species that have a big effect on community species BECAUSE they are the most abundant species in that community Ecosystem Engineers Dramatic effect on the habitats in which species live They physically change the environment Mullerian Mimicry Both species look like each other and they re both chemically defended Batesian Mimicry A harmless species mimics a dangerous specie Resource Partitioning Interspecific between species Character displacement Intraspecific Within a species Intraspecific competition is stronger than interspecific Mitosis Cell Replication How many copies of each gene exist in a cell at G1 and G2 of interphase G1 2 and G2 4 Correct sequence of steps in the eukaryotic cell cycle G1 S phase G2 mitosis cytokinesis ALL cells must replicate their DNA before they divide Sister chromatids are formed in the S phase when chromosomes undergo Replication Eukaryotes Mitosis somatic cells Bacteria and Archaea Binary Fission Binary Fission two identical cells Mitosis 2 identical daughter cells only in somatic cells Chromosomes Chromosomes in Eukaryotes contain DNA histone proteins Chromosomes include Two identical double stranded DNA It is one long molecule of DNA per each chromosome Bacterial Achaea Cell Replication 1 DNA replication 2 Cell must double in size cytoplasm lipids everything for a new daughter cell 3 Once the cell has copied the constriction starts pinching in until the cell has gone through cytokinesis Key role in Mitosis in Eukaryotes Growth Development repair Asexual Reproduction Steps in Mitotic Cell Division G1 S G2 Mitosis Cytokinesis Interphase M phase S phase is where DNA replication occurs Composed of two sister chromatids combined together During Interphase DNA strands are unspooled and analyzed Mitosis Steps Prophase chromosomes condense and the duplicated centrosomes radiate to opposite sides Pro metaphase Spindle fibers mictrotubules attach to the chromosomes preparing for a pull Metaphase The spindle fibers attach to the chromosomes and the chromosomes align down the center of the cell Anaphase Sister chromatids are separated they are now considered separate chromosomes Telophase Nuclear Envelope forms around the new chromosomes and cytokinesis occurs Population Calculations Lambda New population Old Population rmax is at optimal conditions When birth rates are at the highest possible and death rates are at the lowest possible Exponential growth It is density independent and occurs when the r value does not change over time Carry Capacity density dependent logistic growth model Population Regulation negative biotic factors predation parasitism disease NOT COMPETITION