Biology Chapter on Ecology and Photosynthesis

Photosynthesis and Cellular Respiration

• Photosynthesis is the process where plants, algae, and some bacteria convert light energy into chemical energy stored in glucose.
• The word equation for photosynthesis is: Carbon dioxide + Water + Light energy → Glucose + Oxygen
• The reactants in photosynthesis are carbon dioxide (CO2), water (H2O), and light energy.
• The products of photosynthesis are glucose (C6H12O6) and oxygen (O2).
• Cellular respiration is the process by which organisms break down glucose to generate energy (ATP).
• The word equation for cellular respiration is: Glucose + Oxygen → Carbon dioxide + Water + Energy (ATP)
• The reactants in cellular respiration are glucose (C6H12O6) and oxygen (O2).
• The products of cellular respiration are carbon dioxide (CO2), water (H2O), and ATP (energy).
• Photosynthesis and cellular respiration are interconnected; the products of one become the reactants of the other, sustaining life.

Trophic Levels

• Producers: create energy-rich compounds via photosynthesis (e.g., plants, algae).
• Primary Consumers: Herbivores that feed on producers (e.g., rabbits, deer).
• Secondary Consumers: Carnivores or omnivores that feed on primary consumers (e.g., snakes, foxes).

Types of Interactions

• Parasitism: One organism benefits, the other is harmed (e.g., ticks on deer).
• Mutualism: Both organisms benefit (e.g., bees and flowers).
• Competition: Organisms compete for resources (e.g., food, habitat).
• Predation: One organism preys on another (e.g., lions hunting zebras).
• Commensalism: One organism benefits, the other is unaffected (e.g., barnacles on whales).

Population Dynamics

• Exponential Growth: rapid population increase under ideal conditions (J-shaped curve).
• Carrying Capacity: the maximum population size an environment can support sustainably (S-shaped curve).

Invasive Species

• Definition: Non-native species that disrupt ecosystems.
• Examples: Zebra mussels, kudzu vine, cane toads

Biogeochemical Cycles

• Nitrogen Cycle: Conversion of nitrogen between atmospheric, soil, and biological forms.
• Phosphorus Cycle: Movement of phosphorus through rocks, soil, water, and organisms.

Carbon Cycle

• Exchange of carbon among the atmosphere, oceans, soil, and living organisms. Includes photosynthesis and respiration.

Water Cycle

• Movement of water through evaporation, condensation, precipitation, and infiltration.

Earth's Spheres

• Biosphere: All living organisms.
• Atmosphere: Gaseous layer around Earth.
• Hydrosphere: Water bodies.
• Lithosphere: Earth's crust and landforms.

Eutrophication

• Excess nutrients (nitrogen and phosphorus) in water cause algal blooms, reducing oxygen levels and harming aquatic life.

Bioaccumulation and Biomagnification

• Bioaccumulation: Build-up of toxins in an organism over time.
• Biomagnification: Increase in toxin concentration as it moves up the food chain.

Biodiversity and Climate Change

• Loss of species due to habitat destruction, pollution, and climate shifts.
• Impacts ecosystems, food security, and global health.

Conservation of Biodiversity

• Habitat preservation and restoration.
• Establishing protected areas (national parks).
• Reducing pollution, recycling, and sustainable practices.
• Controlling invasive species.

Renewable and Non-Renewable Energy Sources

• Renewable: Solar, wind, hydro, geothermal, biomass.
  • Advantages: Sustainable, less pollution.
  • Disadvantages: Intermittent availability, high initial costs.
• Non-renewable: Coal, oil, natural gas, nuclear.
  • Advantages: High energy output, reliable.
  • Disadvantages: Limited supply, environmental damage.

Electrostatic Series

• A list of materials arranged based on their tendency to gain or lose electrons.

Ohm's Law and Circuits

• V = I x R (Voltage = Current x Resistance)
  • V: Voltage (Volts, V)
  • I: Current (Amperes, A)
  • R: Resistance (Ohms, Ω\OmegaΩ)
• Series Circuits: Current (I) is the same throughout the circuit, and voltage (V) is divided across components.
• Parallel Circuits: Current (I) is divided across branches and voltage (V) is the same across each branch.
• Resistance (R) : total R = R1 + R2 + R3...

Factors Affecting Resistance

• Material: Conductors have lower resistance; insulators have higher resistance.
• Length: Longer wires have higher resistance.
• Thickness: Thicker wires have lower resistance.
• Temperature: Higher temperatures usually increase resistance.

Static vs. Current Electricity

• Static electricity: Accumulation of electric charge on a surface; charges do not flow.
• Current electricity: Continuous flow of electric charge through a conductor; requires a closed circuit.

Atomic Theory and Key Scientists

• John Dalton: Atoms are indivisible particles (incorrect), atoms of the same element are identical, atoms combine in whole-number ratios.
• J.J. Thomson: Discovered electrons using a cathode ray tube, proposed the 'Plum Pudding Model'.
• Ernest Rutherford: Conducted the gold foil experiment, discovered the nucleus.
• Niels Bohr: Proposed that electrons orbit the nucleus in specific energy levels.

Bohr-Rutherford Diagrams

• Represent the arrangement of subatomic particles (protons, neutrons, electrons) in an atom.
• Nucleus: Contains protons (+) and neutrons (neutral).
• Electron shells: Surround the nucleus, each holding a specific number of electrons.

Counting Atoms in a Compound

• Example: C6H12O6 (glucose).

Standard Atomic Notation

• Format: Z/AxX, where:
  • A: Mass number (protons + neutrons).
  • Z: Atomic number (protons).
  • X: Element symbol.

Determining Atomic Details

• Atomic Number: Number of protons.
• Mass Number: Protons + Neutrons.
• Number of Neutrons: Mass Number - Atomic Number.
• Number of Electrons: Equal to protons in a neutral atom.

Reactivity and Atomic Structure

• Reactivity increases down Group 1 (alkali metals), decreases down Group 17 (halogens).

Particle Theory of Matter

• Matter is made up of tiny particles that are in constant motion and are attracted to one another.

Physical and Chemical Properties

• Physical properties: Quantitative (measurable) and Qualitative (Observable).
• Chemical Properties: Describe a substance's ability to react.

Subatomic Particles

• Protons: Positively charged, found in the nucleus.
• Neutrons: No charge, found in the nucleus.
• Electrons: Negatively charged and orbit the nucleus.

Families of Elements

• Alkali Metals (Group 1): Highly reactive, 1 valence electron.
• Alkaline Earth Metals(Group 2): Reactive, 2 valence electrons.
• Halogens (Group 17): Very reactive nonmetals, 7 valence electrons.
• Noble Gases (Group 18): Inert, full outer shell

Ions

• Cations: Positively charged ions (lose electrons).
• Anions: Negatively charged ions (gain electrons).

Mixtures and Pure Substances

• Mixtures: Combination of substances retaining their properties.
  • Homogeneous: Uniform (e.g., saltwater).
  • Heterogeneous: Not uniform (e.g., sand and water).
• Pure Substances: Fixed composition.
  • Elements: Made of one type of atom.
  • Compounds: Made of two or more elements bonded.

Density

• Formula: Density = Mass/Volume
• Units: g/cm³ or kg/m³

Drawing Common Compounds

• Example: Water (H₂O): Two hydrogen atoms bonded to one oxygen atom.

Pure Substances vs. Mixtures/Elements vs. Compounds

• Pure Substance: Uniform properties throughout.
• Mixture: Combination of substances.
• Element: Single type of atom.
• Compound: Two or more elements chemically combined.

Importance of Earth's Tilt

• Causes seasons by changing the angle of sunlight throughout the year.

Inner vs. Outer Planets

• Inner (Terrestrial): Small, rocky, closer to the Sun, higher densities (Mercury, Venus, Earth, Mars).
• Outer (Gas Giants): Large, gaseous, farther from the Sun, lower densities (Jupiter, Saturn, Uranus, Neptune).

Canadian Contributions to Space Exploration

• Canadarm, Canadarm2, Chris Hadfield, RADARSAT.

Challenges and Hazards for Astronauts

• Microgravity: Muscle and bone loss.
• Radiation: Exposure to harmful cosmic rays.
• Psychological stress: Isolation, confinement.
• Health issues: Altered fluid distribution.

Definition of Celestial Objects

• Celestial Objects are natural objects found in space (e.g., stars, planets, moons, asteroids, comets, galaxies)

Earth's Rotation and Revolution

• Rotation: Earth spins on its axis, causing day and night.
• Revolution: Earth orbits the Sun, taking 365.25 days and causing seasons.

Astronomical Unit

• The average distance from Earth to the Sun. (approximately 149.6 million km).

Asteroid Belt

• Located between Mars and Jupiter.
• Contains rocky remnants from the early solar system.
• Largest object: Ceres.

Constellations

• Patterns of stars in the night sky (e.g., Orion, Ursa Major, Scorpius).

Why Ancient Cultures Studied the Skies

• Navigation
• Tracking time
• Religious and cultural significance

Lunar and Solar Eclipses

• Lunar Eclipse: Earth passes between the Sun and the Moon, casting a shadow on the Moon.
• Solar Eclipse: The Moon passes between the Sun and the Earth, blocking sunlight.

Big Bang Theory

• Explained the origin of the universe.
• Universe began as a singularity and has been expanding.

Solar Nebula Theory

• Explained the formation of a solar system.
• Solar system formed from a rotating cloud of gas and dust about 4.6 billion years ago.

Galaxies

• A massive system of stars, planets, gas, dust, and dark matter bound by gravity.
• Types of Galaxies include: Spiral, Elliptical, Irregular.