Taxonomy and Classification

Taxonomy and Classification

• Taxonomy involves naming and categorizing living organisms.
• Carl Linnaeus created the classification system over 250 years prior.
• The classification system is based on shared physical and structural features.
• Binomial Nomenclature identifies organisms using a two-part name.
  • The two parts are the genus and the species.
  • Acer rubrum (Red Maple) exemplifies Binomial Nomenclature.
  • The genus is Acer (maple trees).
  • The species is rubrum (a specific type of maple).
  • Binomial names are italicized, with the genus underlined if handwritten.
• The seven levels of classification include Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Kingdoms of Life

• Eubacteria are unicellular, prokaryotic, and microscopic.
  • Some Eubacteria have Flagella are whiplike structures that enable some unicellular organisms, particularly Eubacteria, to move in their environment..
  • Their cell walls are composed of peptidoglycan.
  • Examples include Escherichia coli, Cyanobacteria, Borrelia burgdorferi, and Staphylococcus aureus.
  • Eubacteria are gram-positive or gram-negative.
• Archaebacteria are unicellular, prokaryotic, and reproduce asexually, and some produce methane
  • They inhabit extreme environments like hot springs, salty lakes, and deep-sea vents.
  • Examples include Euryarchaeota, Bathyarchaeota, and Lokiarchaeota.
• Protista are plant-like, animal-like, or fungi-like, mostly aquatic, and contain membrane-bound organelles
  • They can be autotrophic or heterotrophic.
  • Examples include red algae, Amoeba, Euglena, and Plasmodium.
• Fungi are eukaryotic heterotrophs with cell walls and act as decomposers.
  • They are filamentous, composed of hyphae, reproduce sexually or asexually.
  • Examples include pennybun, wood ear, corn smut, and liberty cap.
• Plantae are multicellular, non-motile, and photosynthetic, and contain photosynthetic pigments
  • They reproduce sexually and asexually.
  • Examples include cacti, roses, tomatoes, peace lilies, and orchids.
• Animalia are multicellular, heterotrophic, and motile (can move).
  • They lack cell walls, possess sensory and excretory organs, and reproduce sexually.
  • Examples include dogs, cats, horses, lions, and tigers.

Classification Keys

• Dichotomous Keys identify organisms using a series of choices.
• An example of a dichotomous key:
  • Does the specimen come from a maple tree?
    • Yes → proceed to the next question.
    • No → it is not a maple leaf.
  • Do the lobes form a V or U shape?
    • V → it is a silver maple leaf.
    • U → it is a sugar maple leaf.

Symbiotic Relationships

• Symbiosis encompasses close associations between two species.
  • Mutualism benefits both organisms. An example is lichens and algae.
  • Commensalism benefits one organism, with no effect on the other. An example is clownfish and sea anemones.
  • Parasitism benefits one organism while harming the other. An example is tapeworms and humans.

Plant Biology

• Plants consist of two main types: vascular and non-vascular.
  • Non-vascular plants lack vascular tissue (e.g., mosses, liverworts).
  • Vascular plants possess specialized tissues for transport (e.g., ferns, trees, flowers).
• Plant parts include roots, stems, leaves, and flowers.
  • Roots absorb water and nutrients.
  • Stems support the plant and transport substances.
  • Leaves conduct photosynthesis.
  • Flowers facilitate reproduction.
• Transport occurs via xylem and phloem.
  • Xylem transports water and minerals from roots to leaves.
  • Phloem transports sugars and nutrients from leaves to the rest of the plant.
• Stomata are tiny openings on leaves.
  • Stomata control gas exchange and water loss.
• Adaptation refers to traits that aid survival in an environment.
  • Desert plants possess thick stems for water storage and reduced leaves to minimize water loss.
  • Aquatic plants have large air spaces for flotation and stems that are flexible.
  • Cold environment plants have needle-like leaves to minimize water loss.
• Invasive species are non-native organisms thriving and harming ecosystems.
  • Examples include zebra mussels and purple loosestrife.
• Exotic species are non-native species introduced to a new area, and may compete with native species for resources.
• Plant biodiversity is important.
  • It provides oxygen, food, medicine, and habitat.
  • It maintains ecosystem stability and resilience.
  • It protects against climate change and habitat destruction.