Biological Classification

🌱 Biology: Biological Classification

Why classify?

• To relate & understand between many through DNA, cell, biomolecules, structural similarities.

• Taxonomy → a classification program.

Classification

• Puts organisms into groups (cladogram = tree).

• Classification lists → lists organisms in group based on traits (characteristics).

• Binomial Nomenclature → (scientific naming system).

• Taxonomy → study of classifying (how we group, based on traits, judging structures).

• Phylogeny → study of traits through evolutionary history.

🔹 Groups: Largest to Smallest

• Domain

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

👉 General to specific → to specific to general

🔹 3 Domains = based on cell type

1. Archaea

2. Bacteria

3. Eukarya

🔹 6 Kingdoms

1. Archaebacteria

   • unicellular prokaryote

   • auto/heterotroph

   • extreme environments

2. Eubacteria

   • unicellular prokaryote

   • auto/heterotroph

   • everywhere

3. Protista

   • unicellular eukaryote

   • auto/heterotroph

4. Fungi

   • multicellular eukaryote (mushrooms)

   • heterotroph (absorbs nutrients)

5. Plantae

   • multicellular eukaryote

   • autotroph (photosynthesis)

6. Animalia

   • multicellular eukaryote

   • heterotroph (ingest nutrients)

🔹 Final 7 Levels (Example: Humans)

1. Kingdom: Eukaryota – (Eukaryote cell)

2. Phylum: Animalia – (Animal cells, heterotroph)

3. Class: Mammalia – (All mammals)

4. Order: Primates – (All primates)

5. Family: Hominidae – (Bipedal primates)

6. Genus: Homo – (Humans + Neanderthals)

7. Species: Homo sapiens – (Humans only)

🔹 Species

• Smaller, most specific, most fertile.

• Same species → reproduce.

🔹 Binomial Nomenclature

• (Bi = two, Nomial = name).

• Last two classification groups (genus + species) are used to create unique name for each species.

• Ex: Ursus arctos (Grizzly Bear) + Ursus maritimus (Polar Bear).

• Latin is used = dead language.

• Genus is capitalized, species is not; both are italicized.