B2 - Classifying and Naming Organisms

B2 - Classifying and Naming Organisms

• Ecologists use taxonomy to consistently classify species and their relatives, crucial for discussing population distribution and diversity.
• Taxonomy is the practice of classifying living things.

I Can...

• Explain fundamental principles of taxonomy and binomial nomenclature.

Classifying Organisms

• All living organisms are classified into three domains: Archaea, Bacteria, and Eukarya.
• Archaea: Ancient bacteria, often living in extreme environments.
• Bacteria: Bacteria not classified as Archaea, found in various environments.
• Eukarya: Eukaryotic organisms (with nuclei), encompassing a broader range of life forms, including plants, animals, and fungi.

Domains of Life

• Archaea: Prokaryotic cells (no nucleus), single-celled organisms, live in extreme environments (e.g., heat, pH, salinity). Can be autotrophs or heterotrophs. Examples include halophiles and methanophiles.
• Bacteria: Prokaryotic cells (no nucleus), single-celled organisms, live in less extreme environments. Can be autotrophs or heterotrophs. Examples include cyanobacteria and E. coli.
• Eukarya: Eukaryotic cells (with nucleus), single-celled or multicellular organisms, live in less extreme environments. Can be autotrophs or heterotrophs. Examples include plants, animals, protists, and fungi.

Classifying Organisms (Levels of Classification)

• A system of eight levels classifying organisms from general to specific.
• 1. Domain
• 2. Kingdom
• 3. Phylum
• 4. Class
• 5. Order
• 6. Family
• 7. Genus
• 8. Species.
• This system, excluding domain, was developed by Carolus Linnaeus.

Example: Bobcats

• Showing the classification of bobcats to highlight their relationships with other organisms.
• Bobcats are classified within the domain Eukarya, kingdom Animalia, and so on.

Naming Systems

• Most organisms are classified using binomial nomenclature.
• Binomial nomenclature is a two-part naming system using genus and species names.
• Examples include Homo sapiens (humans), Rana tigrina (a type of frog), and Pisum sativum (peas).
• Scientific names are italicized and use Latin or Greek words.

Binomial Nomenclature (Special Rules)

• Genus: Includes several species, capitalized first letter, can be written alone.
• Species: Never written alone; lowercased.

Binomial Nomenclature

• Organisms with similar anatomy, embryology, and evolutionary history are more closely related.
• For example, grizzly, Alaskan brown, and polar bears all belong to genus Ursus, suggesting a relationship.

Changing Names

• DNA sequencing allows scientists to verify organism classification.
• Skunks, for example, have been reclassified, suggesting newer knowledge based on DNA analysis.

Dichotomous Keys

• Dichotomous keys guide identification of organisms using a series of paired descriptors.
• An easy method of sorting organisms based on their visual characteristics.
• Used in taxonomy to make classification more efficient.
• Examples of dichotomous keys to identify flowers and leaves.

Test your knowledge on key concepts in biological classification with this quiz. Explore the characteristics of the genus, species statements, and the role of dichotomous keys in ecology. Additionally, discover recent discoveries affecting classification systems.