Component 2

• Classification is the process of naming and organizing organisms into groups based on their characteristics and evolutionary history
• The classification of an organism can change as new information becomes available
• The seven groups in the hierarchy of taxons, from largest to smallest, are: Kingdom, Phylum, Class, Order, Family, Genus, Species
• The five kingdom classification system categorizes organisms into Animalia, Fungi, Plantae, Prokaryotae, and Protoctista
• The three domain classification system categorizes organisms into Archaea, Bacteria, and Eukarya
• The three domain system of classification was developed by analyzing molecular differences between organisms to determine their evolutionary relationships
• Organisms in the same domain share a distinctive pattern of ribosomal RNA
• Bacteria is one of the three domains, consisting of 'true' bacteria, also known as Eubacteria
• Archaea is one of the three domains, made up of primitive bacteria existing in extreme environments, also known as Archaebacteria
• Eukarya is one of the three domains, consisting of all eukaryotic organisms
• The kingdom Prokaryotae features:

  • Unicellular prokaryotes
  • Lack a true nucleus and membrane-bound organelles
  • Rigid cell wall
• The kingdom Plantae features:

  • Multicellular eukaryotes
  • Photoautotrophs
  • Cellulose cell walls
• The kingdom Animalia features:

  • Multicellular eukaryotes
  • No cell wall
  • Heterotrophic
  • Nervous coordination
• The kingdom Fungi features:

  • Eukaryotes
  • Heterotrophic
  • Chitin cell walls
  • Grow by producing branching filaments, hyphae
  • Asexual reproduction via spores
• The kingdom Protoctista features mainly unicellular eukaryotes with no differentiation into tissues
• Different types of evidence used in classification include observations (e.g., fossils) and biochemical methods (e.g., DNA genetic fingerprinting)
• DNA profiling is a method of determining the characteristics of an individual's DNA, using shared DNA or proteins between species to estimate relatedness
• The advantage of using biochemical methods of classification is reducing mistakes made from observing physical features alone due to morphological convergence
• Homologous features are similar due to shared ancestry, while analogous features are similar due to convergent evolution
• Homologous features have evolved from the same structure for different functions and indicate a common ancestor
• Analogous features are structures that have evolved independently for the same function
• Example of a homologous feature: Pentadactyl limb (found in mammals, birds, and reptiles)
• Example of an analogous feature: The wings of birds and insects
• Species: A group of organisms that can interbreed to produce fertile offspring
• Two components of a binomial name:

  • Generic name: the Genus to which the organism belongs
  • Specific name: the species the organism belongs to
• Advantage of the binomial naming system: It is universal; an organism’s binomial name is the same everywhere in the world
• Biodiversity: The number and variety of living organisms in a given region, affected by environmental, genetic, and human factors
• Mechanism that has generated biodiversity: Natural selection
• When measuring biodiversity of a habitat, ecologists must consider species richness and species evenness
• Species richness: The number of different species found within an area
• Species evenness: The number of individuals of each species living together in a community
• Biodiversity in a habitat can be assessed using Simpson’s Diversity Index
• Simpson’s Diversity Index:

  • A measurement of diversity considering both species richness and evenness
  • Value between 0 and 1, where greater value indicates greater biodiversity
• Genetic diversity within a species can be calculated using the proportion of polymorphic gene loci
• Polymorphism: The presence of different phenotypes among members of a single species
• Biodiversity can be assessed at the molecular level using DNA fingerprinting and sequencing
• DNA sequencing: Determining the entire DNA nucleotide base sequence of an organism
• DNA sequencing is used to measure biodiversity by identifying variation in base sequences among members of the same species
• Adaptation: A feature of an organism that increases its chance of survival in its environment
• Types of adaptation:

  • Anatomical: changes to physical features
  • Physiological: changes to bodily processes
  • Behavioural: changes to actions