Taxonomic Systems

• Plants and animals are so numerous that knowing all kinds is difficult, even for trained experts.
• Approximately 1.5 million animal species have been described, with more being discovered.
• Around 380,000 plant species have been described, and this number also continues to grow.
• Plants and animals exhibit diversity in form, with some closely resembling each other, while others are very different.
• Some plant and animal species are abundant and widespread, while others are rare and localized.
• Naturalists (biologists, zoologists, botanists, and microbiologists) seek systems for accurately naming and grouping all plant and animal species.
• This process of naming and grouping organisms is called Systematics.

Taxonomic Systems

• Systems of classification have been developed based on the understanding that plants and animals are related through common descent.
• These classification schemes express the phylogenetic relationships and diversity between groups of organisms.
• Systematics is the scientific study of the diversity of organisms and their relationships, focusing on classification, nomenclature, and identification.

Aims of Systematics

• Discover and describe new species.
• Classify organisms into hierarchical taxa.
• Reconstruct evolutionary relationships.
• Understand the processes that shape biodiversity.

Branches of Systematics

• Taxonomy: Naming and classifying organisms.
• Phylogenetics: Reconstructing evolutionary relationships between organisms.
• Phylogeography: Studying the geographic distribution of species and populations.

Taxonomic Ranks/Categories

• Taxonomic ranks are hierarchical categories used to classify living organisms.

• These ranks are used to classify animals into groups and subgroups for easier study and understanding.

• To facilitate easier study, a system of nomenclature (method of naming animals) has been developed.

• Phyla is the largest groups in the animal kingdom.

• Each phylum is divided into a number of classes.

• Each class is divided into a number of orders.

• Each order is divided into a number of families.

• Each family is divided into a number of genera (singular: genus).

• Each genus is divided into a number of species.

• The classification of Anopheles gambiae (the malaria mosquito) is an example of taxonomic classification.

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Diptera
  • Family: Culicidae
  • Genus: Anopheles
  • Species: Anopheles gambiae

• Another example is the classification of Plasmodium falciparum.

  • Phylum: Apicomplexa
  • Class: Aconoidasida
  • Order: Haemosporidea
  • Family: Plasmodiidae
  • Genus: Plasmodium
  • Species: Plasmodium falciparum

• Additional taxonomic ranks/categories may be added for easier management of large groups.

  • Subphylum (below Phylum)
  • Subclass (below Class)
  • Suborder (below Order)
  • Subfamily (below Family)
  • Subgenus (Below Genus)
  • Subspecies (below Species)

Important Terms

• Species: A group of interbreeding organisms.
• Phylogeny: The study of the evolutionary history of organisms.
• Taxa (singular: Taxon): Units representing groups of organisms with shared characteristics.

Taxa Characteristics

• Monophyletic: Descended from a common ancestor (e.g., birds and reptiles).
• Paraphyletic: Descended from a common ancestor, excluding some descendants (e.g., reptiles excluding birds).
• Polyphyletic: Descended from a common ancestor, including animals with similar characteristics (e.g., body shape) but different ancestry.
• Species: Individuals that are similar in body shape and structure, produce fertile offspring, and are reproductively isolated from other groups.
• Species is the real category in the system of classification.
• All other categories are based on the species category and are considered abstractions.

Zoological Nomenclature:

• International Committee on Zoological Nomenclature establishes rules for guidance of taxonomists to standardize procedures.
• Linnaeus in 1758, devised Binomial system of nomenclature in the book Systema Natura.
• Assigning two names to every species of Animal or Plant.
• Specific name distinguishes the species,
• While generic is the other name that is usually kept at the beginning before the specific one.

Nomenclature Construction:

• Both the specific and generic should be constructed in latinized forms, either printed in italics or underlined if handwritten.
• Generic names must always start in capital letter while specific starts in small letters - Anopheles gambiae, for example.
• The addition or abbreviation of scientist helps specifies is to avoid semantics problem, and to show who first specified to the part.

Scientific Name Changes:

• The indication of bracketing scientific name indicates the scientific name change.
• This further indicated the changing of the name.
• The absence of formal way implies one can differ and bring in all version, so it's important to know and indicate the different versions for specification.
• Problems of semantics occur due to different governing factors and in result there often is versioning of results.
• Always use the safest name to prevent problems of semantics.

Homology:

• Homology is the existence of shared characteristics or structures because multiple species went threw shared evolutionary history.
• Examples of shared features include,
  • forelimbs in vertebrates i.g. Whales and humans.
  • Eye parts of multiple organisms, i.g. Flies

Analogy Homology:

• Possess similarity in their dna structure, i.g Possession of similar protein sequences.
• They help encode simular structure with Haemoglobin in Humans.
• They help conserve DNA regions and promoters.
• Developmental Homology helps display certain stages threw genetics to identify their evolutionary history.
• Conservation shows the conservation to the genes.

Homology Types:

• Homology's are of three types, including.
  • Orthology - Existence of homologers genomes or protein, helps identify multiple genomes and similarities as it's been passed on.
  • Parology- Existence of protein with the same genetics, it's similar to humans and helps with identification of genetics, i.e: Haemoglobin. Analogy - has structure which share similar form, they help with study but aren't derived from birds and insects.

Classification:

• It comes with taxonomic categories.
• In relation to the unit of classification, it helps classify with related data for identifying.

Subdivided Classification:

• Begin with the species and use what data is related to identity evolution and categories to indicate related species.

Insect Classification

• The process involves organizing organisms, each known as classification that make is related towards specific categories.
• Relatability and organization is important for what level and classifications are made.
• Five main types for categories of the insect classification that are mainly for classification.
  • Speciles- helps group into general.
  • General- help group into families
  • Order- grouping species in families.
  • Classification- helps order classes into what's phyla.