1. Evolution is a central theme in biology2. Life Contains an order of structural levels with each level building on the levels beneath it3. Each level of biological organization has emergent properties4. Life has the ability to acquire material and energy5. Structure and function are related6. Living things reproduce and cells are the basic unit of structure and functionCells7. DNA is the basis of heritable information8. DNA also provides the instructional methods that guide the growth and development of multicellular organisms9. Organisms have the ability to maintain their structure and regulate their internal environment.Essential Elements of LifeSubatomic ParticlesAtomic NumbersElectron Distribution and Chemical PropertiesAtoms in living systems (and their Valence)Covalent BondsElectronegativityNon-polar Covalent BondsPolar Covalent BondsIonic BondsHydrogen BondsVan der Waals InteractionsVan der Waals ForcesMolecular Shape and FunctionWater and the Fitness of the EnvironmentDissociation of Water and the pH ScaleCarbon and the Molecular Diversity of LifeUnit 1 Notes- To date, about 1.8 million species have been identified and named- With so many different species there are many different unifying similarities.1. Evolution is a central theme in biology- The ability to evolve is built into organisms- Evolution is a change in the genetic makeup (DNA) of a population over time as a result of natural selection. A single individual cannot evolve, populations evolve.- Evolution can happen at different speeds for different types of organisms. - Natural selection is the driving force behind evolution. It means that evolution is not a level playing field—organisms are not equally suited to reproduce; certain individuals are more suited than others to reproduce- Evolution is based on two principles: variation and competition (individuals will struggle to survive)o If individuals are different, one has a better change of surviving than the other. Think of a race—one is more suited to run faster than the other.o Giraffe example—the ones who already had slightly longer necks were able to survive because they could reach their food. The giraffes with the shorter necks died out, thus leaving the longer giraffes to reproduce and create more giraffes with longer necks.- There are variations within every species (e.g., some are tall some are short)- Means some are “better” suited to survival (natural selection, aka survival of the fittest)- Variability comes from genes and genes are inherited.- Conclusion: more “good” genes survive and therefore the population changes. You cannot straighten your hair and expect your children to have straight hair because you are not altering your genetic makeup).2. Life Contains an order of structural levels with each level building on the levels beneath it- Hierarchy of biological organization—within a living thing, there are simple levels of organization that combine to make more and more complex levels of organization.1. Biosphere: all of the environments on Earth that are inhabited by life (land, water, and several layers of atmosphere). A biosphere is made up of several ecosystems.2. Ecosystems: all living things in a particular area, along with non-living environmental components with which life interacts (soil, water, air components, light) Example—in a classroom, the ecosystem is all the people, chairs, walls, air, etc.3. Community: the entire array of living organisms inhabiting a particular ecosystem. An ecosystem is made up of communities.4. Population: individuals of a species living within the bounds of a particular area.5. Organism: individual living things. A population is made up of organisms.6. Organ System and Organ: body part consisting of 2 or more tissues, which carries out a specific function within an organism (e.g., liver, kidney, etc.)7. Tissue: group of cells from similar embryonic origins that combine to form organs. Tissue is made up of cells.8. Cell: the fundamental unit of structure and function in life (e.g., neuron, hepatocyte). The smallest living thing on the planet is a single-cell organism. A virus is not a living thing (it is a nucleic acid) because it has no cells.9. Organelle: various functional components that make up cells (e.g., chloroplast, mitochondria)10. Molecule: chemical structure consisting of 2 or more atoms (e.g., chlorophyll in plants).11. Atom: basic unit of matter (e.g., hydrogen). Matter includes living and non-living things—everything is made up of atoms.12. Subatomic particle: all units of matter small than the atom (e.g., protons, neurons, electrons, and lots of others…)3. Each level of biological organization has emergent properties- Emergent property—a property that emerges as a result of interactions between components as complexity increases. Think of it as taking apart your house—the wiring, cement, cabinets, etc. are not interacting in a specificway if you pile all the materials together. They are not creating the organism (your house) until they are put together.- If you mix all of the components of a chloroplast together in a test tube, photosynthesis will not occur.o The molecules must interact in a specific way- With each step up in biological hierarchy new emergent properties are seen. For example, if you take sodium and chlorine, you have table salt. The table salt is the emergent property because it was not found in either of the individual substances.4. Life has the ability to acquire material and energy- All living things must obtain energy- The material and energy are often transformed- Energy—the ability to do work.- All levels of biological organization are thermodynamically “open systems”o Exchanging energy (heat and work) and matter with their environment.- The sun is necessary to provide the energy for the producers in our ecosystem. If there were a nuclear explosion, there would be so much dust and dirt lingering in the air that sunlight wouldn’t be able to penetrate the dust and reach the earth. If something were able to survive the explosion, it would either die of starvation or because of the drop in temperature.- There must be an exchange of energy between an organism and its environment.- See figure 1.5 about energy flow and transformation in the ecosystemo The sun gives energy to the producers (plants and other photosynthetic organisms). The energy is lost in heat and chemical energy. The chemical energy affects the organisms on earth
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