GENETIC CONCEPT

• Recessive gene


  A gene that is only expressed when two copies are present
• Punnett Square

  A diagram used to help predict the possible genotypes and phenotypes of offspring from a particular cross or breeding experiment
• Two types of breeding methods

  1. Monohybrid

  2. Dihybrid
• Monohybrid

  Breeding involving one trait
• Dihybrid

  Breeding involving two traits
• Punnett Square is a simple and handy diagram used to predict the possible genotypes and phenotypes of offspring
• Punnett Square was introduced by Reginald Punnett
• Heredity


  How some traits are passed from parents to their children
• Genes


  Small sections of DNA that are coded for specific traits
• Genes are found on chromosomes
• Humans have two sets of 23 chromosomes - one set from each parent
• Alleles

  Two forms of a gene (dominant & recessive)
• Dominant gene

  Stronger of two genes expressed in the hybrid; represented by a capital letter (R)
• Recessive gene

  Gene that shows up less often in a cross; represented by a lowercase letter (r)
• Homozygous genotype


  Gene combination involving 2 dominant or 2 recessive genes (e.g. RR or rr); also called pure
• Heterozygous genotype


  Gene combination of one dominant & one recessive allele (e.g. Rr); also called hybrid
• Punnett Square


  • Used to help solve genetics problems
• Monohybrid cross


  Cross happening in the F1 generation offspring of parents differing in one trait only
• Dihybrid cross


  Cross happening in the F1 generation offspring of parents differing in two traits
• Punnett Square was introduced by Reginald Punnett, a British geneticist
• Biological Species Concept

  Gives scientists a snapshot of the evolution of new species in many groups of plants and animals
• Biological species

  All of the populations of individuals that can actually or can potentially interbreed with each other in nature to produce fertile offspring
• Taxonomic classification system (Linnaean system)

  • Hierarchical model
  • Moves from general to more specific groups
  • Ends at the species level
• Binomial nomenclature

  System of giving living things a two-part name, which is Latinized
• Binomial nomenclature comprises the scientific name of the organism which includes the genus and species name
• Biodiversity

  Variety of living things
• Biodiversity

  • Keeps ecosystem stable
  • Provides medicinal potential of plants/animals
  • Benefits the earth and all its
• Low biodiversity

  Few prominent species and a low number of other species within the habitat
• High biodiversity

  Habitat or ecosystem that has a high number of different species
• How to conserve biodiversity

  • Reforestation
  • Establishment of sanctuaries
  • Sustainable use of forest resources
  • Combating exotic species
• Producers

  Bacteria and algae that can convert energy from the sun into chemical energy and store it as food
• Photosynthesis

  Uses water, carbon dioxide, and sunlight
• Plants make much more food each day than they need, excess glucose is converted into starch and stored
• Consumers

  Organisms that consume food for their energy supply
• Trophic level

  The position an organism holds in a food chain
• Trophic levels

  • Primary producers
  • Primary consumers
  • Secondary consumers
  • Tertiary consumers
  • Quaternary consumers
• Energy moves from one trophic level to another in an ecosystem
• Primary producers (autotrophs) are the base of every food chain
• Primary consumers are herbivores that eat primary producers
• Secondary consumers are carnivores and omnivores that eat primary consumers