Biology: Biodiversity and Dynamics

• Biodiversity is the variety of all living things and includes diversity in genetics, species, and ecosystems
• Species

  A population or group of populations where the members have similar physical characteristics and the capacity to interbreed and produce fertile offspring
• Species


  • Emperor penguins (Aptenodytes forsteri)
• Species

  Genetically isolated from each other - reproductive isolation - they DO NOT interbreed under normal conditions to produce fertile offspring
• Phenotype


  The appearance of an organism, a direct expression of its genotype (genetic makeup) and the effects of the environment
• Species diversity


  • Different types of species found within the same area
• Population


  Members of one species that interbreed (live) together in a particular place and at a particular time
• Community


  Represents all of the living organisms (populations) found living together in a particular area or habitat
• Components of a community

  • Producers
  • Consumers
  • Decomposers
• Interactions between organisms in a community

  • Competition
  • Predation
  • Symbiosis
• Competition

  Organisms compete for the same resources like light, space, territory, water, mate, oxygen and food
• Predation

  One organism feeds on or eats another live organism
• Predation defence mechanisms

  • Physical (thorns, spikes, hairs, waxy secretions)
  • Chemical (toxic chemicals)
• Types of symbiotic relationships

  • Mutualism (both organisms benefit)
  • Commensalism (one organism benefits, the other is unharmed)
  • Parasitism (the prey is harmed or eaten)
• Types of nutrition


  • Autotrophic (make their own food)
  • Heterotrophic (feed on other organisms)
• A community has several trophic levels
• Ecosystem


  The sum of all of the organisms living in a particular area, along with the habitat and physical component of the environment that affects organisms
• Habitat


  • Provides organisms with the basic resources they need to survive including optimum temperature, oxygen, water, breeding sites, and shelter
• Genetic bottleneck


  Human activity and natural disasters cause a rapid decrease in the number of individuals in a population, reducing genetic diversity
• Genetic diversity


  Variety of genes and forms of the genes that occur within a particular species
• Genetic diversity plays an important role in the survival and adaptability of a species
• If a population has a diverse set of genes, it is more likely to survive changing environmental conditions
• A community that has greater biodiversity is more stable
• Communities with greater species diversity have more extensive food webs that are more interconnected
• Biological classification

  Allows scientist to identify, study, and share information about a biological species
• Artificial classification

  Organisms are organised into groups based on a limited number of similar characteristics
• Artificial classification

  • The dolphin, turtle, fish, platypus, crab, and duck are all aquatic organisms
  • The ladybug, hawk (bird), and duck are all capable of winged flight
  • The ladybug and crab both have exoskeletons
  • The hawk, ladybug, crab, turtle, platypus and duck lay fertilised eggs
• Using a dichotomous key

  Further statements are made using a different characteristic until all organisms have been placed into a subgroup
• Natural classification

  • Considers the degree of evolutionary relationship among organisms
  • Organises species into groups based on inherited characteristics from a common ancestor - homologous characteristics
• Homologous characteristics

  • Have an underlying similarity of structure and position regardless of function
• Basis of classification

  • Physical features
  • Reproductive strategies
• Molecular sequencing


  Basic similarities between different organisms can be linked to similarities in their DNA and proteins
• Hierarchical classification (Taxons)


  • Grouping of organisms that share some common features including molecular similarities
  • The groups are positioned in a hierarchical order called taxonomic ranks or taxa
• Domains

  • Archaea (prokaryotes)
  • Bacteria (prokaryotes)
  • Eukarya (eukaryotes)
• Kingdoms

  • rod shaped – unicellular, like bacteria
  • Spiral – live in harsh environments
  • round – amoeba
  • Euglena
  • flowering plants
  • yeasts
  • moulds
  • mammals
  • alga
  • mosses
  • mushrooms
  • birds
  • fish
• Classifying the common Koala

  1. Domain: Eukarya

  2. Kingdom: Animalia

  3. Phylum: Chordata – backbone - vertebrate

  4. Class: Mammalia – hair, fur, warm blooded, suckle young

  5. Order: Diprotodontia – 2nd and 3rd digits on rear feet fused

  6. Family: Phascolarctidae

  7. Genus: Phascolarctus

  8. Species: Phascolarctus cinereus
• Binomial nomenclature


  • System of taxonomy introduced by Carl Linnaeus in the 18th century
  • Each species has two Latin names (a binomen)
  • The first name identifies the genus, always written with a capital
  • The second name identifies the species within the genus, always written in lower case
• Binomial nomenclature

  • Eucalyptus globulus
  • Callistemon macropunctatus
• Scientific names vs common names

  • Scientific names identify the genus and species of an organism, written in Latin
  • Common names are easily recognizable but do not include any scientific information about the genus or species
• Scientific name vs common name

  • Domestic cat (common name) - Felis catus (scientific name)