Core Concepts in Biology, Geology, and Astronomy

Animal Classification

Vertebrates: Possess an endoskeleton and belong to the phylum Chordata. They are divided into 5 main groups:

• Mammalia (Mammals)
• Aves (Birds)
• Reptilia (Reptiles)
• Amphibia (Amphibians)
• Pisces (Fish)

Invertebrates: Often possess an exoskeleton or lack a backbone. Examples include:

• Cnidarians (e.g., jellyfish)
• Arthropods (e.g., insects, spiders)
• Molluscs (e.g., snails, clams)
• Worms (various phyla)

Kingdom Monera

Monera: Consists of prokaryotes (organisms lacking a true nucleus).

Plant Biology Basics

Vascularity refers to whether plants have specialized tissues (veins) for transporting water and nutrients.

• Xylem: Transports water and minerals upwards from the roots.
• Phloem: Carries glucose (food produced during photosynthesis) around the plant.

Cell Theory

1. All organisms are composed of one or more cells.
2. Cells are the basic unit of life, structure, and function in organisms.
3. New cells are created from pre-existing cells.

Microscopy

Microscope Adjustment Knobs:

• Coarse Adjustment Knob: Used for large focusing movements (big knob).
• Fine Adjustment Knob: Used for small, precise focusing adjustments (small knob).

Types of Microscopes:

• Compound Microscope: Provides high magnification (up to ~1500x) and produces a 2D image.
• Stereo Microscope (Dissecting Microscope): Used for viewing larger specimens at lower magnification (up to ~200x) and produces a 3D image.

Cell Types and Structure

Unicellular organisms consist of a single cell.

Multicellular organisms consist of multiple cells.

• Prokaryotes: Lack a nucleus and membrane-bound organelles.
• Eukaryotes: Possess a nucleus and membrane-bound organelles.

Key Eukaryotic Cell Organelles:

• Cytoplasm: The jelly-like substance filling the cell, containing organelles.
• Vacuoles: Membrane-bound sacs involved in storage (e.g., water, nutrients, waste) and maintaining structure.
• Ribosomes: The site of protein synthesis.
• Mitochondria: The "powerhouse" of the cell; site of cellular respiration, generating ATP.
• Chloroplasts (in plant cells and some protists): Site of photosynthesis; contain chlorophyll.

Cell Division

• Meiosis: Produces four genetically different haploid cells (gametes).
• Mitosis: Produces two genetically identical diploid cells (for growth and repair).

Transport and Gas Exchange

Osmosis: The movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration.

Stomata (pores on leaves): Facilitate gas exchange, including the release of oxygen and uptake of carbon dioxide.

Plant Reproduction

Asexual Reproduction Methods:

• Budding
• Grafting
• Cuttings

Flower Parts (Sexual Reproduction):

• Carpel (Pistil - female part): Consists of the Stigma (sticky top part that receives pollen), Style (stalk connecting stigma to ovary), and Ovary (contains ovules).
• Stamen (male part): Consists of the Anther (produces pollen) and Filament (stalk supporting the anther).

Human Biology Snippets

Skin Layers:

• Epidermis (outer layer)
• Dermis (middle layer)
• Subcutaneous fat layer (innermost layer)

Circulatory System Vessels:

• Arteries: Carry blood away from the heart; generally have thick, muscular walls.
• Veins: Carry blood back to the heart; often contain valves to prevent backflow.
• Capillaries: Tiny vessels connecting arteries and veins; walls are one cell thick, facilitating exchange of gases, nutrients, and waste.
• Pulmonary Vein: Notably carries oxygenated blood from the lungs back to the heart.

Microorganisms

• Bacteria: Kingdom Monera, prokaryotic, typically small. Have a cell wall (made of peptidoglycan, different from plants/fungi). May possess flagella for movement.
• Protozoa: Kingdom Protista, eukaryotic, generally larger than bacteria. Have an outer membrane, sometimes a pellicle for structure.
• Fungi: Eukaryotic, do not perform photosynthesis (no chloroplasts). Have a cell wall made of chitin.

Harmful Microorganisms/Effects: Include pathogens (disease-causing organisms) and microorganisms contributing to eutrophication (excess nutrient enrichment in water bodies, leading to oxygen depletion).

Geology: Rocks and Minerals

Rocks are naturally occurring solid masses composed of minerals or mineral-like matter.

Minerals are naturally occurring, inorganic crystalline solids with a definite chemical composition and a specific internal crystal structure (lattice). Note: All minerals form crystals, but not all crystals are minerals (e.g., sugar crystals).

Properties Used to Identify Minerals:

• Hardness (resistance to scratching)
• Lustre (how light reflects off the surface, e.g., shiny, dull)
• Streak (color of the mineral's powder)
• Crystal Form
• Cleavage/Fracture
• Color
• Specific Gravity (density)

Major Rock Types

• Igneous Rocks: Formed from the cooling and solidification of molten rock (magma or lava). Often characterized by interlocking crystals.
  • Extrusive Igneous Rocks: Formed from lava cooling quickly on the Earth's surface.
• Sedimentary Rocks: Formed by the accumulation, compaction, and cementation of sediments (pieces of other rocks, minerals, organic matter).
• Metamorphic Rocks: Formed when existing igneous, sedimentary, or other metamorphic rocks are transformed by heat, pressure, or chemical reactions without melting.

Astronomy Milestones

• Eratosthenes: Accurately calculated Earth's circumference, determined Earth's axial tilt, and contributed to the concept of the leap day.
• Moon Phases: The cycle of the Moon's appearance from Earth, progressing from waning (decreasing visible illumination) to waxing (increasing visible illumination), including phases like crescent and gibbous.
• Ptolemy Model: An ancient geocentric model, placing Earth at the center of the universe.
• Nicolaus Copernicus: Proposed the revolutionary heliocentric model, placing the Sun at the center. His work faced opposition and was banned by the Church until 1822.
• Galileo Galilei: Used telescope observations (e.g., phases of Venus, moons of Jupiter) to provide strong evidence supporting the heliocentric model.

Earth's Spheres

• Biosphere: Encompasses all the parts of Earth where life exists.
• Hydrosphere: Includes all of Earth's water (oceans, lakes, rivers, groundwater, ice).
• Atmosphere: The layer of gases surrounding the Earth.