Module2: Intro to Zoology

Zoology

• It encompasses various aspects, from the structure of organisms to the subcellular level.

• Basic Zoology

• Focuses on gaining knowledge of animals for its own sake.

• Applied Zoology

• Focuses on information that directly benefits humans and animals (e.g., medicine).

Aristotle

• He grouped animals based on their reproduction and habitat.

Carolus Linnaeus

• a Swedish botanist, developed the binomial system of genus and species, which is still used today.

• He also established taxonomy, the science of classification.

Aristotle

•  emphasized classifying animals based on:

• Way of living

• Actions

• Habits

• Body parts

• He observed insects, fishes, birds, and whales.

Aristotle

• He created insect orders such as Coleoptera and Diptera.

• Considered the "father of biological classification".

John Ray

•  is recognized for his early work in modern taxonomy.

• His book "Synopsis Methodica Animalium Quadrupedum et Serpentini Generis" (1693) divided animals into those with blood and those without.

John Ray

• He classified animals based on gills, lungs, claws, teeth, and other structures.

• Provided the first good definition of the species as a reproducing unit.

• Michael Adamson (1727-1806),

• a French botanist, stressed using multiple characters for classification.

  • His concept led to the development of numerical taxonomy.

• Lamarck (1744-1829)

• attempted to improve the Linnaean system.

  • Published "Histoire Naturelle des Animaux sans Vertebres" (seven volumes).

  • Arranged animals according to evolution, using a branching tree representation.

  • Marked the beginning of using phylogeny in systematics.

• Cuvier (1769-1832)

• insisted on including extinct fossil forms in classification.

• Divided animals into four branches:

  • Vertebrata: fishes to mammals

  • Mollusca: molluscs and barnacles

  • Articulata: annelids, crustaceans, insects, and spiders

  • Radiata: echinoderms, nematodes, and coelenterates

• Vertebrata

• Mollusca

• Articulata

• Radiata

4 branches of animals:

• Vertebrata

• fishes to mammals

• Mollusca

• molluscs and barnacles

• Articulata

• annelids, crustaceans, insects, and spiders

• Radiata

• echinoderms, nematodes, and coelenterates

• Charles Darwin

• in his 1859 book "Origin of Species", introduced the evolutionary concept.

• This concept was readily accepted by biologists.

• Taxonomy became an important evidence for evolution.

• Encouraged taxonomists to see Darwin's theory as a foundation for their work.

• E. Mayr (1942)

• defined species as "groups of interbreeding natural populations."

  • His book "New Systematics" became a landmark in taxonomy.

Taxonomy

systemetics

classification

• Three core scientific ideas are involved in grouping organisms:

• Taxonomy

• "The theory and practice of classifying organisms" (E. Mayr, 1966).

• Systematics

• Classification of living things based on their natural relationships.

• Classification

• The process of ordering animals into groups based on their relationships.

• Taxon

• A taxonomic group of any rank that is distinct enough to be assigned a definite category.

• Species

• Considered the most important taxon, representing a natural unit.

typological

nominalistic

biological

3 concepts of species

• Typological Species Concept:

• Based on essentialism, recognizing species by their morphological characteristics.

• Nominalistic Species Concept:

• Views species as man-made ideas, with nature producing individuals rather than species.

• Biological Species Concept:

• The most widely accepted concept, defines species as "groups of interbreeding natural populations that are reproductively isolated from other such groups."

phenetic or numerical

cytotaxonomy

chemotaxonomy

paleotaxonomy

nomenclature

5 Methods of taxonomy

• Phenetic Method or Numerical Taxonomy:

• Groups individuals based on overall similarity.

  • Operational Taxonomic Unit (OTU): The desired size of clusters or groupings.

  • Similarity/dissimilarity is measured on a scale of 0 to 1, with 1 representing perfect identity and -1 representing dissimilarity.

  • Involves extensive data collection and statistical analysis using computers.

• Operational Taxonomic Unit (OTU):

• The desired size of clusters or groupings.

• Cytotaxonomy:

• Characterization and identification of a cell's complete chromosome set (karyotyping).

  • Karyotypes within a species are generally consistent.

  • Chromosomal variations between species provide insights into evolutionary relationships.

• Chemotaxonomy:

• Utilizes information about small molecules produced by enzymes.

  • Tools include:

    • Protein fractions in electrophoresis

    • Amino acid identification in chromatography

    • Prevalence of isoenzymes in tissues

  • Presence of specific pheromones, color pigments, and toxins are also used for classification.

• Palaeotaxonomy:

• Relies on identification and dating of fossils.

  • Complete fossils provide better identification possibilities.

  • Fossils are studied along with their geological context and other accompanying fossils.

  • While assigning fossils to higher taxa is possible, determining species is not always feasible.

• Nomenclature Methods

• Nomenclature provides a system for naming and referencing organisms.

  • Essential part of taxonomy.

identification keys

• Essential for identifying animals.

• Includes printed materials, computer software packages, and comparisons with type specimens.