Classification and evolution

• Classification is the process of naming and organizing organisms into groups based on their characteristics
• The eight groups in the classification hierarchy, from largest to smallest, are Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
• An organism can be classified into Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species, from largest to smallest
• A binomial name consists of two components:

  • Generic name: the genus the organism belongs to. Two closely related species will share the same genus.
  • Specific name: the species the organism belongs to
• The advantage of the binomial naming system is that it is universal; an organism’s binomial name is the same everywhere in the world
• The five kingdoms are Prokaryote, Protoctista, Fungi, Plantae, Animalia. The three domains are Bacteria, Archaea, Eukaryota
• Organisms are classified into a kingdom based on similarities in observable characteristics
• The domain system of classification was developed by analyzing molecular differences between organisms to determine their evolutionary relationships (phylogeny)
• Classification is simply sorting organisms into groups, while phylogeny investigates the evolutionary relationships between organisms
• Natural selection results in evolution through random mutations creating new alleles, some of which provide advantages against selection pressures, leading to the evolution of new characteristics in individuals and their offspring
• Darwin and Wallace contributed to the theory of evolution by observing that birds with beak shapes most suited to the food they eat are more likely to survive and pass this trait to their offspring
• Evidence for the theory of evolution includes fossils for comparing extinct organisms to current ones, genomic DNA sequencing showing relationships to primates, and molecular evidence of shared proteins among organisms
• Variation is caused by genetic factors like mutations and environmental factors such as climate and diet
• Intraspecific variation is within the same species, while interspecific variation is between different species
• Continuous variation exists as gradual changes over a range (e.g., height), while discontinuous variation exists as distinct categories (e.g., blood group)
• Spearman’s rank correlation coefficient is calculated to measure the correlation between two variables, showing how changing one variable affects the other
• Spearman’s rank results closer to 1 indicate a more positive correlation, closer to -1 a more negative correlation, and around 0 no correlation
• Three types of adaptation are anatomical (changes to body structure), physiological (changes to bodily processes), and behavioral (changes to actions)
• Organisms from different taxonomic groups may show similar features because they adapted to similar environments, like marsupial moles and placental moles living in different continents but sharing similar anatomical features
• Implications of evolution for humans include bacterial antibiotic resistance making infections harder to treat and pesticide resistance potentially leading to the destruction of entire crops
• Divergent evolution is when interbreeding species evolve into different species with different adaptations
• Convergent evolution is when species evolve in similar ways due to similar environmental pressures
• Phylogenetic tree: A diagram that shows the evolutionary relationships between organisms.
• Geographical allopatric speciation is when a population splits into two or more species due to geographical isolation
• Taxonomy: the branch of science concerned with classification, especially of organisms.
• Classification: A system of organizing organisms into groups based on shared characteristics.
• Phylogeny: the branch of biology that deals with the evolutionary relationships among organisms
• Why do we classify organisms?

  • For convenience of study
  • identifying new species
  • To see evolutionary links
  • Predict characteristics
  • mating/crossing strains
• Cladograms: Diagrams that show the evolutionary relationships between organisms.
• Things common in Animalia:

  • Eukaryotic
  • Multicellular
  • heterotrophs
  • movement
  • sexual reproduction (usually)
• Heterotrophes: organisms that obtain energy from other organisms
• Things common in plants:

  • Eukaryotic
  • multicellular
  • CELLULOSE cell wall
  • Autotrophes - chlorophyll system
• autotrophes: organisms that make their own food from inorganic molecules
• Things common in Fungi:

  • Eukaryotic
  • multicellular but coenocytic, some are unicellular
  • Hyphal with CHITIN cell wall
  • Complex sex - spores asexually and mating strains
  • Saprophytic
  • Heterotrophic decomposers and parasites
• Coenocytic: A cell that has two nuclei, one in each nucleolus.
• Saprophytic: A type of fungus that feeds on dead organic matter.
• Hyphal: A long, thin, branched structure that is produced by a fungus.
• Things common in protoctists:

  • Eukaryotic
  • unicellular (colonial cells)
  • Autotrophic or heterotrophic
  • Animal and plant features
  • some fungal spores behave just like protoctisits
• Things common in Prokaryotic:

  • No nucleus - naked loop of DNA
  • no membrane bound organelles
  • Eubacteria or Archeabacteria
  • Different ribosomes and genetic mechanisms from eukaryotic
  • do not contain plastids
• plastids: organelles that contain chloroplasts and are found in plant cells