Lecture 5: Fundamentals of Biology

Species of the Day

• Common Name: Wandering albatross

• Scientific Classification:

  • Kingdom: Animalia

  • Phylum: Chordata

  • Class: Aves

  • Order: Procellariiformes

Role of Sunlight in Ecosystems

• Sunlight serves as the primary energy source / first step in ecosystems

Photosynthesis Overview

• Process Includes:

  • Solar Energy

  • Inputs: CO₂, H₂O

  • Output: Oxygen released into the environment

  • Produced: Glucose (C6H12O6)

  • Role of Enzymes: Involved in converting energy forms (ATP)

  • Example: Seaweed as a photosynthesizing organism

Building Blocks of Life

• Macromolecules: Large molecules important for life

• Four Major Classes:

  1. Carbohydrates

  2. Lipids

  3. Proteins

  4. Nucleic Acids

Carbohydrates

• Definitions:

  • Translation: “Carbon water”

  • Composition: Typically C, H, and O in a 1:2:1 ratio

  • Types:

    • Monosaccharides: Simple sugars (e.g., glucose)

    • Disaccharides: Two monosaccharides linked (e.g., sucrose)

    • Polysaccharides: Long chains of monosaccharides

• Examples of Polysaccharides:

  • Glycogen: Energy storage in animals

  • Starches: Energy storage in plants

  • Cellulose: Structural component of plant cell walls

  • Chitin: Structural component in invertebrate exoskeletons

Energy Flow in Ecosystems: Primary Production vs. Respiration

• Photosynthesis:

  • Participants: Autotrophs only

  • High-Energy Output: Glucose + O₂

• Respiration:

  • Participants: Autotrophs and heterotrophs

  • Low-Energy Stage: Chemical energy transfer

Lipids

• Definition: Includes fats, oils, and waxes

• Composition: Primarily C and H

• Types:

  • Triglycerides: Energy storage and insulation

  • Steroids: Chemical messengers

  • Waxes: Protective coatings

Proteins

• Definition: Polymers of amino acids

• Types:

  • Polypeptides: Chains of amino acids that fold into complex structures

• Functions:

  • Structural components of tissues

  • Enzymatic functions

  • Chemical transport (e.g., hemoglobin)

Nucleic Acids

• Definition: Polymers of nucleotides

• Types:

  • DNA: Deoxyribonucleic acid, double-stranded, contains genetic information

  • RNA: Ribonucleic acid, usually single-stranded, involved in protein synthesis

Protein Synthesis: Central Dogma

• Process:

  1. Transcription: DNA to mRNA in the nucleus

  2. Translation: mRNA to protein in the cytoplasm

Levels of Organization

• Cell: Basic unit of life

• Tissue: Groups of similar cells

• Organ: Structures composed of multiple tissue types

• Organ System: Groups of organs working together

• Multicelled Organism: Collection of different cell types

Classification of Biological Systems

• Levels: Biosphere, Ecosystem, Community, Population, Individual, Organ System, Organ, Tissue, Cell, Organelle, Molecule, Atom

Cell Diversity

• Types of Cells:

  • Prokaryotic Cells: Lack nucleus; unicellular

  • Eukaryotic Cells: Have a nucleus; can be unicellular or multicellular

Organelles in Eukaryotic Cells

• Nucleus: Contains DNA

• Mitochondria: Site of cellular respiration

• Golgi Complex: Processes and transports proteins

• Ribosomes: Protein synthesis sites

• Chloroplasts: Photosynthesis sites in plants

Osmosis in Cells

• Definition: Diffusion of water across a membrane from high to low concentration

• Types:

  • Hypotonic: Lower concentration of solute

  • Hypertonic: higher concentration of solute

Osmoregulation

• Freshwater species: Manage water through active transport and large urine volume

• Marine species: Consume sea water and produce small volumes of urine

Thermal Classification of Animals

• Ectotherms: Body temperature aligns with external conditions

• Endotherms: Maintain body temperature independently of the environment

• Examples:

  • Ectotherms: Most fish and invertebrates

  • Endotherms: Mammals and birds

Introduction to Ecology

• Definition: Study of interactions between organisms and their environment

Population Dynamics

• Population: Group of individuals of the same species

Types of Interactions Among Organisms

• Competition: Intraspecific and interspecific

• Predation: Predator-prey relationships

• Symbiosis: Includes mutualism, commensalism, and parasitism

Competition Types

• Intraspecific: Same species compete for resources

• Interspecific: Different species compete for resources

Symbiosis Types

• Mutualism: Both species benefit

• Commensalism: One benefits, the other is unaffected

• Parasitism: One benefits at the expense of the other