Biology Ecosystems and Interactions

Biology Study Notes

• Biosphere Components: Earth's biosphere includes four interconnected spheres: lithosphere (land), hydrosphere (water), atmosphere (air), and biosphere (all living organisms).

• Energy Flow: Ecosystems transfer energy. Photosynthesis converts carbon dioxide and water into glucose and oxygen. Cellular respiration reverses this, using glucose and oxygen to produce energy, carbon dioxide, and water. Only 10% of energy moves to the next trophic level.

• Matter Cycling: The nitrogen cycle involves bacteria fixing nitrogen, plants absorbing it, and decomposition returning it to the atmosphere. The carbon cycle includes photosynthesis (absorbing CO2) and respiration/combustion (releasing CO2).

• Ecological Interactions: Key interactions include predation (one organism hunting another), competition (organisms vying for resources), mutualism (both organisms benefit), commensalism (one benefits, the other is unaffected), and parasitism (one benefits, the other is harmed).

Chemistry Study Notes

• Matter Classification: Matter is classified as pure substances (elements or compounds), which are one type of atom or molecule, or mixtures (solutions or mechanical mixtures), which contain two or more substances.

• Periodic Table: The periodic table organizes elements. Groups (vertical columns) show similar properties, and periods (horizontal rows) indicate increasing energy levels.

• Atomic Structure: Atoms contain protons (+), neutrons (neutral), and electrons (-). Atomic mass equals the sum of protons and neutrons.

• Chemical Bonding: Ionic bonding occurs between a metal and non-metal through the transfer of electrons. Covalent bonding happens when non-metals share electrons.

Physics Study Notes

• Ohm's Law: Voltage (V) equals current (I) times resistance (R): V = IR.

• Circuits: Series circuits have the same current, and resistance adds up. Parallel circuits have the same voltage, and total current adds up.

• Static Electricity: Objects can become charged through friction, contact, or induction.

Astronomy Study Notes

• Earth-Moon System: The Earth-Moon system involves phases of the moon, eclipses, and tides.

• Life Cycle of Stars: Stars develop from nebulae, go through main sequence stages, expand into red giants, and eventually collapse into white dwarfs or black holes.

• HR Diagram: The Hertzsprung-Russell (HR) diagram plots stellar brightness against temperature to classify stars