Zoology Lecture Prelims PDF

PRELIMINARY 24-25 Chapter 1: Life: Biological Principles and the Science of Zoology Lesson Objectives: Uses of Principles in Zoology Zoology is the scientific study of animal life. Studying animals through scientific principles allows for a deep understanding of life’s pro...

PRELIMINARY 24-25 Chapter 1: Life: Biological Principles and the Science of Zoology Lesson Objectives: Uses of Principles in Zoology Zoology is the scientific study of animal life. Studying animals through scientific principles allows for a deep understanding of life’s processes. These principles include laws from physics, chemistry, and the scientific method. — life shares a common evolutionary origin, knowledge gained from studying one species may provide insights into others. Fundamental Properties of Life 1. Chemical Uniqueness Living systems are composed of macromolecules which are uniquely organized, unlike non-living matter. Macromolecules: Nucleic acids Proteins Carbohydrates Lipids 2. Complexity and Hierarchical Organization Life exhibits a complex structure, from macromolecules to species, where new characteristics emerge at each level, a phenomenon called emergence— driven by evolution Hierarchical Levels of Biological Complexity PRELIMINARY 24-25 Time of Fields of Study Methods of Study Emergent Properties Level Reproduction Cell Hours (e.g., Cell biology, Microscopy Chromosomal mammalian cell molecular (light and replication ~16 hours) biology electron), (mitosis/meiosis) biochemistry , macromolecule synthesis (DNA, RNA, proteins, lipids) Organism Hours to days Organismal Dissection, Structure and (unicellular); anatomy, genetic crosses, coordination of physiology, clinical studies, tissues, organs, days to years genetics physiological and systems (multicellular) experimentation (blood pressure, body temperature, sensory perception, feeding) Population Up to Population Statistical Social structures, thousands of biology, analysis of mating systems, years population variation, age distribution, genetics, abundance, variation levels, ecology geographical natural selection distribution effects Species Thousands to Systematics, Study of Formation of millions of evolutionary reproductive new species, years biology, barriers, reproductive community phylogeny, isolation, ecology paleontology, adaptive ecological evolution interactions Levels of Structural Organization 1. Chemical: Atoms and molecules. 2. Cellular: Cells, the basic unit of life. 3. Tissue: Groups of similar cells. 4. Organ: Structures made of tissues. 5. System: Groups of organs working together. 6. Organismal: Individual living entities. PRELIMINARY 24-25 3. Reproduction Living organisms reproduce at various levels: the molecular, cellular, organismal, species level. Genes — replicate Cells— divide Organism— reproduce (sexually / asexually) Population — fragments Species — split 4. Possession of a Genetic Program Organisms inherit traits through Nucleic acids, DNA, which store genetic information and guide protein synthesis through a universal genetic code. Nucleic Acids: Encode proteins for development and function. DNA: Long, linear chain of nucleotides storing genetic information. (Jasmes Watson and Federick Crick) Genetic Code: Links DNA base sequences to amino acid sequences in proteins. 5. Metabolism Living organisms acquire nutrients and perform metabolic processes (digestion, respiration, synthesis) to maintain themselves. 6. Development Organisms undergo a characteristic life cycle with developmental changes from origin to adulthood. 7. Environmental Interaction Organisms constantly interact with their environments, a study known as ecology, and respond to stimuli, a property called irritability. PRELIMINARY 24-25 8. Movement Life is characterized by controlled movements, from cellular processes to the migration of populations. Branches of Zoology Entomology: Study of insects. Herpetology: Study of reptiles and amphibians. Ichthyology: Study of fishes. Mammalogy: Study of mammals. Ornithology: Study of birds. Parasitology: Study of parasites. Protozoology: Study of protozoans. Taxonomy: Study of the classification of organisms. Scientific Method The scientific method involves: 1. Observation. 2. Question formation. 3. Hypothesis (educated guess). 4. Empirical testing through experiments, involving control and test groups. 5. Conclusions based on data analysis. 6. Publication and repetition to validate findings. PRELIMINARY 24-25 Key terms: Independent variable (IV): The factor that is changed. Dependent variable (DV): The observed outcome. Controlled variables: Factors kept constant during the experiment. Example: Problem: Does aspirin lower blood pressure? Hypothesis: If aspirin is taken daily, blood pressure will decrease. ○ IV: aspirin intake ○ DV: Blood pressure ○ CV: age, gender, dosage of aspirin, duration of the experiment, and dietary and activity levels of participants. PRELIMINARY 24-25 Chapter 2: Chemistry of Life Molecules and Compounds Molecule: Two or more identical atoms chemically combined. Compound: Two or more different atoms chemically combined. Chemical Reactions Synthesis Reaction: A+B→AB ○ Description: Atoms or molecules combine. ○ Energy: Absorbed for bond formation. Decomposition Reaction: AB→A+B ○ Description: Molecule is broken down. ○ Energy: Released. Inorganic vs. Organic Compounds Inorganic Compounds ○ Characteristics: Lack carbon, simpler. ○ Examples: Water (H₂O), salts, acids, bases. Organic Compounds ○ Characteristics: Contain carbon, usually covalently bonded. ○ Examples: Carbohydrates, lipids, proteins, nucleic acids. Organic Compounds: Biomolecules 1. Carbohydrates are one of the primary types of biomolecules, composed of carbon, hydrogen, and oxygen, typically in a ratio of 1:2:1 (CH₂O). They serve as a key source of energy and structural materials in both plants and animals. PRELIMINARY 24-25 ❖ Types of Carbohydrates: Monosaccharides (Simple Sugars): Basic units of carbohydrates. Examples: ◆ Glucose: Primary energy source in cells. ◆ Fructose: Found in fruits. ◆ Galactose: Found in dairy products. Disaccharides (Double Sugars): Formed by the bonding of two monosaccharides through a dehydration reaction. Examples: ◆ Sucrose: Common table sugar, composed of glucose and fructose. ◆ Lactose: Milk sugar, made of glucose and galactose. ◆ Maltose: Formed from two glucose molecules. Polysaccharides (Complex Carbohydrates): Long chains of monosaccharides (usually glucose) linked together. Examples: ◆ Glycogen: Stored in animal cells (liver and muscles) as a form of energy. ◆ Cellulose: Provides structural support in plant cell walls; humans cannot digest cellulose, but it is an important source of dietary fiber. ◆ Starch: The main form of stored energy in plants, found in foods like potatoes and grains. ◆ Chitin: A structural component found in the exoskeletons of insects and arthropods. Monosaccharides and Sugar Classifications: Tetroses: Monosaccharides with 4 carbon atoms. Pentoses: Monosaccharides with 5 carbon atoms (e.g., ribose, a component of RNA). Hexoses: Monosaccharides with 6 carbon atoms (e.g., glucose, fructose, galactose). PRELIMINARY 24-25 2. Lipids ○ Elements: Carbon, hydrogen, oxygen. ○ Characteristics: Carbon and hydrogen outnumber oxygen, insoluble in water. ○ Types: Neutral Fats (Triglycerides): Stored energy. Saturated: Solid at room temperature (animal fats). Unsaturated: Liquid at room temperature (plant fats). Phospholipids: Cell membranes. Steroids: Cholesterol, hormones. 3. Proteins ○ Components: Amino acids linked by peptide bonds. ○ Elements: Carbon, hydrogen, oxygen, nitrogen, sometimes sulfur. ○ Functions: Enzymatic: Accelerate reactions. Structural: Support (e.g., collagen). Storage: Store amino acids. Transport: Move substances (e.g., hemoglobin). Hormonal: Coordinate activities (e.g., insulin). Contractile: Movement (e.g., actin, myosin). Defensive: Protection (e.g., antibodies). ○ Levels of Organization: Primary: Sequence of amino acids. Secondary: Coiling or folding. Tertiary: 3D shape from R-group interactions. Quaternary: Association of multiple polypeptide chains. 4. Nucleic Acids ○ Function: Blueprint of life. ○ Components: Nucleotides (nitrogenous base, sugar, phosphate group). ○ Types: DNA: Deoxyribonucleic acid; stores genetic information. RNA: Ribonucleic acid; transfers information from DNA. PRELIMINARY 24-25 Differences: ○ DNA: Deoxyribose sugar, double-stranded, thymine (T) base. ○ RNA: Ribose sugar, single-stranded, uracil (U) base. ○ ATP: Adenosine triphosphate; energy carrier, replenished by food oxidation. Chapter 3: Cells as Basic Units of Life CELLS 1. Cell Theory: ○ Introduced by Robert Hooke, Mathias Schleiden, and Theodor Schwann. ○ Core principles: 1. All organisms are composed of cells. 2. Cells are the smallest living things. 3. Cells arise from pre-existing cells. 2. Prokaryotic vs. Eukaryotic Cells: ○ Prokaryotes (archaea, bacteria) lack a membrane-bound nucleus. ○ Eukaryotes have a nucleus and complex organelles, including a cytoskeleton. 3. Cell Anatomy: ○ Cells consist of three main regions: plasma membrane, cytoplasm, and nucleus. ○ The plasma membrane operates as a barrier and is composed of a double phospholipid layer with embedded proteins, cholesterol, and glycoproteins. PRELIMINARY 24-25 ○ Specializations include microvilli and membrane junctions for cellular functions like absorption and communication. 4. Organelles: ○ The cytoplasm houses organelles, including ribosomes (protein synthesis), endoplasmic reticulum (RER and SER), Golgi apparatus (modification and packaging), and lysosomes (digestive enzymes). ○ The mitochondria are crucial for energy production through ATP synthesis. 5. Cytoskeleton and Nucleus: ○ The cytoskeleton (microfilaments, intermediate filaments, microtubules) provides structural support. ○ The nucleus contains genetic material (DNA) and is the control center for cellular activity. 6. Cell Division: ○ Mitosis: Produces two identical daughter cells for growth and repair in somatic cells. ○ Meiosis: Produces four haploid gametes, contributing to genetic diversity through processes like crossing over and independent assortment. 7. Transport Mechanisms: ○ Passive Transport (diffusion, osmosis) allows movement without energy. ○ Active Transport requires energy, including processes like solute pumping and bulk transport (endocytosis, exocytosis). TISSUES Animal Tissues: The lecture begins by outlining the four primary types of tissues: ○ Epithelial: Covers and lines body surfaces. ○ Connective: Binds and supports body parts. ○ Muscle: Responsible for movement. ○ Nervous: Sends signals and supports communication. Epithelial Tissue: Found on body surfaces and linings, its functions include protection, absorption, filtration, and secretion. Characteristics: PRELIMINARY 24-25 ○ Cells are tightly packed, avascular, and regenerate easily. Classification: ○ Based on layers: simple (one layer) or stratified (multiple layers). ○ Based on shape: squamous (flat), cuboidal (cube-shaped), or columnar (tall). Examples: ○ Simple squamous epithelium lines the lungs and capillaries. ○ Stratified squamous epithelium provides protection in areas like the skin and mouth. Connective Tissue: The most abundant tissue type, performing functions like binding, supporting, and protecting body tissues. Characteristics: ○ Variations in blood supply (vascularized or avascular). ○ Composed of living cells surrounded by an extracellular matrix. Types of Connective Tissue: ○ Loose connective tissues like areolar and adipose tissue provide cushioning and energy storage. ○ Dense connective tissue forms tendons and ligaments. ○ Cartilage (hyaline, elastic, fibrocartilage) provides structure and cushioning. ○ Bone serves as a rigid framework for support and protection. ○ Blood is a fluid connective tissue responsible for transport. Muscle Tissue: Specialized for contraction and movement. Types: ○ Skeletal muscle: Voluntary, striated muscle that moves bones. ○ Cardiac muscle: Involuntary, striated muscle found in the heart. ○ Smooth muscle: Involuntary, non-striated muscle found in hollow organs. Nervous Tissue: Composed of neurons and supporting neuroglia. Responsible for transmitting electrical signals across the body, enabling communication between different parts of the body. Found in the brain, spinal cord, and nerves. PRELIMINARY 24-25 Body Membranes: The lecture concludes by discussing various body membranes, which serve as protective coverings: ○ Epithelial membranes: Include cutaneous (skin), mucous, and serous membranes. ○ Connective tissue membranes: Primarily consist of synovial membranes found around joints.