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
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