Introduction to Zoology

• Zoology is a science concerning the study of animals
• ZOOL1 Lecture 1 is an introduction to the Science of Zoology

Outline of Topics

• What is an animal?
• Zoology, including its scope and branches
• The Scientific Method
• Theories on the origin of animal life

What Defines a Living Organism/Being?

• Living systems have a unique and complex molecular organization composed of macromolecules: carbohydrates, lipids, proteins, and nucleic acids
• Metabolism consists of biochemical processes and reactions maintaining organisms through anabolism (synthesis) and catabolism (breakdown) of molecules
• Growth increases in size, while development involves progressive changes during an organism's life cycle
• Living organisms interact with their environment, assimilating nutrients and reacting to stimuli
• Genetic information coded in DNA ensures inheritance fidelity
• Reproduction allows organisms to perpetuate, potentially leading to new species
• Adaptation is the biological mechanism for adjusting to new or changing environments
• Organization involves ordered arrangements in living systems, where new characteristics can appear at any level
• Living organisms exhibit precise, controlled movements, unlike non-living things

Theories and Doctrines on the Origin of Life Related to Zoology

• Animals originated in the Precambrian seas over 600 million years ago.
• Big Bang Theory: The universe began from a hot, rotating gas explosion, leading to life through chemical evolution around 13 billion years ago (BYA)
• Earth formed about 4.5 BYA, and life emerged around 3.5 MYA
• Doctrine of Creation: Life was created by a Supreme Being
• Spontaneous Generation: Life originated from non-living things, supported by Aristotle's "On the Generation of Animals" in 350 BC
• Panspermia: Microscopic life forms were introduced from outer space
• Biogenesis: Life arose from other living organisms, supported by Louis Pasteur and Charles Darwin
• Abiogenesis: Life came from non-living or inorganic matter

Levels of Organization

• Atom: Basic unit of matter, consisting of protons, neutrons, and electrons
• Molecule: Smallest fundamental unit of compounds
• Cell: Basic unit of life
• Tissue: Group of similar cells performing a common function
• Organ: Functional unit of an animal body made of more than one tissue type
• Organ System: Association of organs performing an overall function
• Organism: A living creature with interdependent parts
• Population: A group of interbreeding individuals
• Community: Interacting group of various species in a common location
• Ecosystem: Complex of living organisms, physical environment, and their interrelationships in a unit of space
• Biosphere: Life-supporting stratum on Earth's surface

Classifications of Living Organisms

• Prokaryotic cells lack a nucleus (e.g., bacteria)
• Eukaryotic cells possess a nucleus (e.g., protists, fungi, plants, animals)
• Viruses are acellular genetic elements, with their living status debated
• Autotrophic organisms produce their own food (some bacteria, protists, and plants)
• Heterotrophic organisms consume others for food (some bacteria, protists, fungi, and animals)
• Unicellular organisms consist of a single cell (bacteria, protists, some fungi)
• Multicellular organisms are composed of many cells (some fungi, plants, and animals)

What is an Animal?

• Animals are eukaryotic, heterotrophic, and multicellular, lacking cell walls
• All animals share a common evolutionary history and are subject to similar selective forces
• Animals range from simple to complex organisms
  • Protoplasmic level: Functionality in unicellular organisms like protozoa
  • Cellular level: Functionally differentiated cellular aggregates
  • Tissue level: Aggregation of cells organized into definite patterns
  • Organ level: Organs formed for specialized functions
  • Organ system level: Organs working together in a system

Body Systems

• Integumentary (skin, hair, nails): Protects internal organs and absorbs substances
• Nervous (brain, spinal cord, nerves): Body's primary regulatory and controlling system
• Endocrine (various glands): Secondary controlling system through hormone release
• Skeletal (bones, ligaments, joints): Provides movement, support, and visceral organ protection
• Muscular: Facilitates body movement
• Circulatory/Cardiovascular (heart, blood vessels): Transports oxygen and lymph
• Immune (bone marrow, lymphoid organs): Defends against foreign bodies and pathogens
• Respiratory (lungs, airways, skin): Enables gas exchange
• Urinary/Excretory (kidneys, ureters, urethra): Regulates blood volume and removes excretory wastes
• Digestive (mouth, stomach, intestines): Breaks down food for absorption
• Reproductive (gonads, genitalia): Enables reproduction and early development

Zoology Defined

• Zoology studies animals, derived from "zoon" (animal) and "logos" (to study)
• Zoology addresses animal diversity, basic life processes, and habitation of various ecosystems
• Modern zoology is based on laws of physics, chemistry, and the scientific method
• Zoology investigates the origin, history, structure, function, classification, distribution, development, inheritance, significance, relationships, and interactions of living things in their environment

History of Zoology

• Aristotle classified organisms by growth and reproduction, separating animals from plants by movement and sensation, and distinguished humans by their capacity for deep thought
• Carl Linnaeus developed binomial nomenclature (Linnaean System of classification), assigning unique two-part Latin names to animals and establishing a similarity-based hierarchical classification system

Fields of Zoology According to Aspect of Study:

• Molecular Biology: Focuses on the structure, function, and operation of nucleic acids, proteins, and molecular components of cells
• Cytology: Studies cells, including their structure and different types
• Histology: Study of animal tissues
• Organology: Studies specific body organs
• Anatomy: Involves the dissection and study of internal body structures and their functions
• Physiology: Studies the integrative biological functions and biochemical processes of animals
• Developmental Zoology: Studies the embryonic development of animals, and growth to death (embryology)
• Genetics: Examines heredity and variation in organisms
• Pathology: Investigates diseases and malfunctions affecting body organs
• Systematics: Deals with animal classification and evolutionary relationships
• Ecology: Focuses on interactions and relationships of organisms in their environments
• Paleontology: Studies fossils to understand prehistoric life
• Evolutionary Biology: Examines the processes that affect the survival, evolution, and adaptation of organisms

Fields of Zoology According to Type of Animal Species:

• Parasitology: The study of animal parasite species
• Protozoology: The study of protozoans
• Helminthology: The study of worms
• Carcinology: The study of crustaceans
• Malacology: The study of mollusks
• Entomology: The study of insects
• Arachnology: The study of arachnids
• Ichthyology: The study of fishes
• Herpetology: The study of amphibians and reptiles
• Ornithology: The study of birds
• Mammalogy: The study of mammals
• Poriferology: The study of sponges

Being a Zoologist

• Zoology is characterized by being guided by natural law, which must be explanatory, testable, and verifiable, with tentative conclusions
• The scientific method includes:
  • Identifying a problem through observation
  • Formulating a hypothesis as an intelligent guess
  • Experimentation or data collection to test the hypothesis
  • Analyzing and interpreting the gathered data
  • Concluding whether the hypothesis is correct
  • Publishing the findings for public use

The Research Process

• Experimental design involves the framework or scheme used to answer a scientific question
• Types of Hypothesis:
  • Null Hypothesis: States no relationship or effect exists among variables or phenomena
  • Alternative Hypothesis: Suggests a relationship or effect among factors
• Data collection - Qualitative (numerical) and quantitative (descriptive)
• Variables in experiments:
  • Dependent: Factors measured to show the effect of factors
  • Independent: Factors manipulated or tested
• Experimentation set-up involves experimental and control groups
  • Control Group: Expected to show desired results as a reference
  • Experimental Group: the group explored
• Data presentation is done by tables and graphs
• Replicable research lead to testable hypothesis
• Forms of testable approaches in zoology
  • Expiremental research
  • Descriptive research
  • Ethnobiological
  • Predictive/modeling
• Theory: Supported by many experiments and observations
• Paradigm: Guide extensive research, but can refuted by scientific revolution
• Law: What occurs in nature based on observation and experiments
• Principle: Natural which other laws can be based on
• Darwin's Theory of Evolution is guiding zoological research
• Chromosomal Theory of Inheritance is also key to zoological research