Lecture 2. Evolutionary Principles of Animal Behaviour

Introduction to Animals

  • Definition Contexts: Animals can be defined in various contexts:
    • Textbook definitions
    • New Zealand legal definitions (NZ Animal Welfare Act 1999)
    • Animal ethics perspectives
    • Biological context (most life forms on Earth are not vertebrates)

Characteristics of Animals

  • Multicellular Organisms:

    • Animals are composed of more than one cell.

  • Heterotrophic:

    • Animals cannot produce their own food through carbon fixation and must derive nutrition from other organic sources (plants or other animals).

  • Eukaryotic Cells:

    • Animal cells are eukaryotic, meaning they contain a membrane-bound nucleus and lack cell walls that provide structural support.

  • Development from Embryonic Layers:

    • Tissues in animals develop from embryonic layers, which later form various adult body parts.

New Zealand Animal Welfare Act 1999

  • Definition of 'Animal' (according to the Act):
    • Includes live representatives from the animal kingdom such as:
    • Mammals
    • Birds
    • Reptiles
    • Amphibians
    • Fish (both bony and cartilaginous)
    • Mollusks like octopus and crab
    • Excludes humans.

Evolutionary Tree of Life

  • Major Groups of Animals:
    • Deuterostomia: Includes Chordata (vertebrates), Echinodermata, and others.
    • Protostomia: Includes Arthropoda, Mollusca, and many others.
    • Most animal species have diverged from common ancestors over approximately 700 million years.

Classification and Diversity

  • Around 3.7% of animal species are vertebrates.
  • Examples of animal groups with the number of species:
    • Arthropoda ~1,500,000 species
    • Mollusca ~8,500 species
    • Annelida ~12,000 species
    • Cnidaria ~9,000 species

Animal Behavior

  • Behavior Definition:

    • Actions taken by multicellular eukaryotes exhibited in response to stimuli, controlled by muscles and glands through the nervous system.

  • Types of Behaviour:

    • Individual actions (e.g., locomotion, grooming, communication).
    • Collective responses to both internal and external stimuli.

  • Lab Activities for Understanding Behaviour:

    • Analyzing the effect of temperature on movement.
    • Assessing the influence of an observer on behavior measurements.
    • Exploring genetics' contribution to behavior.
    • Observations on food choice and alternative methods for recording behaviour.