Biological Classification Notes

Omithischia and Saurischia

  • These are the two primary divisions of dinosaurs (DINOS).

Biological Classification

  • This is the classification of living things.

Diapsida and Anapsida

  • These are classifications within reptiles/sauropsids.

Sauropsida and Synapsida

  • These are major classifications of amniotes.

Amniota

  • A group of tetrapods (four-limbed vertebrates) whose embryos are protected by amniotic membranes.

Biodiversity Facts

  • There are 13 billion known species of organisms.
  • This represents only 5% of all organisms that have ever lived.
  • New organisms are still being found and identified.

Latin Scientific Names

  • Latin is used for scientific names because it was a language commonly known historically.
  • Example: Skunk
    • French: MOUFFETTE
    • German: SINKTIER
    • Mephitis mephitis: The scientific name using binomial nomenclature.

Systematics and Taxonomy

  • Systematics is the science of naming and grouping organisms.
  • Classification (Taxonomy) is the arrangement of organisms into orderly groups based on similarities.
  • Binomial Nomenclature: The system of giving each species a two-part name.
    • Example: Mountain lion, also known as puma, cougar, panther, or catamount, is Felis concolor.

Binomial Nomenclature Examples

  • Ursus maritimus: Genus Ursus, species maritimus.
  • Acer rubrum: Genus Acer, species rubrum.

Taxonomic Hierarchy

  • Mnemonic: Dumb King Phillip Called Out Fifty Good Soldiers
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

Example: Taxonomy of a Bactrian Camel

  • Species: Camelus bactrianus
  • Genus: Camelus
  • Family: Camelidae
  • Order: Artiodactyla
  • Class: Mammalia
  • Phylum: Chordata
  • Kingdom: Animalia

Example: Taxonomy of a Grizzly Bear

  • Domain:
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Carnivora
  • Family: Ursidae
  • Genus: Ursus
  • Species: Ursus arctos

Linnaean vs. Modern Classification

  • Linnaeus (Original Scientist):
    • Classification based on similarities and differences.
  • Phylogeny:
    • Classification based on evolutionary descent (tree of life).

Cladograms

  • Cladogram: A diagram of evolutionary relationships (phylogeny).
  • Clade: A group of organisms with similar characteristics.
  • Derived characteristics: A trait that arose in the most recent common ancestor of a particular group.

Domains and Kingdoms Classification

  • 3 Domains: Bacteria, Archaea, Eukaryota
  • 4 Eukaryotic Kingdoms: Protista, Fungi, Plantae, Animalia

Domain Bacteria

  • Unicellular and Prokaryotic.
  • Have a cell wall with peptidoglycan for protection.
  • Range from non-harmful organisms living in soil to deadly parasites.
  • Some photosynthesize, while others do not.
  • Some need oxygen, while others are killed by oxygen.

Domain Archaea

  • Prokaryotic and Unicellular.
  • Live in extreme environments such as volcanic hot springs, brine pools, and black mud devoid of oxygen.
  • Cell walls do not contain peptidoglycan.

Domain Eukaryota

  • All eukaryotic, contains 4 Kingdoms.
  • Kingdoms: Fungi, Animalia, Plantae, Protista

Kingdom Protista

  • Eukaryotes that are not members of the plant, animal, or fungi kingdoms.
  • Most are unicellular, but some are multicellular.
  • The largest protists are brown algae (kelp) containing millions of cells.
  • Used to be characterized by “plant-like”, “animal-like”, or “fungus-like” protists, but now have 6 different clades: Excavata, Chromalveolata, Cercozoa, Rhodophyta, Amoebozoa, Choanozoa.

Kingdom Fungi

  • Heterotrophic eukaryotes with cell walls that contain chitin.
  • Chitin is a polymer made of modified sugars that provides a hard structure and shape to cells.
  • Reproduce asexually, releasing spores that travel through air and water.
  • Many fungi feed by releasing digestive enzymes that break down leaves, fruit, and other organic material.
  • Help organisms maintain homeostasis by breaking down dead organisms and recycling essential nutrients.
  • Parasitic fungi can cause serious diseases in plants or animals.
  • Examples: Mushrooms, mold, & yeast.

Kingdom Plantae

  • The lives of plants depend on sunlight, gas exchange, water, and minerals.
  • All plants are eukaryotes, have cell walls containing cellulose, and carry out photosynthesis using chlorophyll.
  • Examples: Green algae, mosses and bryophytes, ferns, seed plants.

Kingdom Animalia

  • Multicellular, heterotrophic, eukaryotic organisms with cells that lack cell walls.
  • Maintain homeostasis by gathering and responding to information, obtaining and distributing oxygen and nutrients, and collecting and eliminating carbon dioxide and other wastes.
  • More than 95% of all animals are invertebrates (no backbone), while less than 5% are Chordates (have spinal chord) and vertebrates (have backbone).

Kingdom Organization Summary

  • Protista: Complex, single-celled, some multicellular; Absorb, photosynthesize, or ingest food; Protozoans, algae, water molds, and slime molds.
  • Fungi: Some unicellular, most multicellular, filamentous forms with specialized complex cells; Absorb food; Molds, yeast, and mushrooms.
  • Plantae: Multicellular form with specialized complex cells; Photosynthesize food; Mosses, ferns, and flowering plants.
  • Animalia: Multi-cellular form with specialized complex cells; Ingest food; Invertebrates, fishes, reptiles, amphibians, birds, and mammals.

Transition to Mammals

  • Early Therapsids -> Later Therapsids -> Morganucondon -> Monotremes -> Marsupials -> Placentals
  • Key Features:
    • Single skull hole behind eye is large.
    • Increase tooth and occlusal complexity.
    • Articular-quadrate used for both hearing and jaw joint. Articular-quadrate convert to ear bones, jaw joint moves
    • One bone in lower jaw
    • Mammary glands, hair, ear bones on skull
    • Develop in pouch - Marsupials
    • Develop in uterus with placenta
    • Live birth, advanced molar tooth shape

Primate Cladogram

  • Five digits on hand and foot, with opposable thumbs
  • Omnivorous
  • Large brain
  • Moveable head and front-facing eyes
  • Four kinds of teeth
  • Central eye area for more acute vision
  • Downward-pointing nose
  • Loss of tail
  • Loss of opposable thumb on foot

Circular Model of the Diversity of Life

  • Animals
  • Plants
  • Fungi
  • Bacteria
  • Archaea
  • Protists