Grade 9

• Natural selection


  If a variation helps an organism survive in a particular environment, that organism will be more likely to reproduce and pass on the variation
• Variations


  Visible differences in physical traits or behaviour observed between organisms
• Adaptations


  Variations that help an organism survive
• Adaptations


  • May be structural (differences in physical traits) or behavioural (differences in how an organism acts)
• Structural adaptation


  • Colour of feathers
• Behavioural adaptation


  • Bears hibernating
• Resource partitioning


  Allows closely related species to co-exist in the same region by using different resources, reducing interspecies competition
• Characteristics of generalists vs specialists

  • Generalists: broad niche, survive in variety of environments, less at risk of extinction
  • Specialists: narrow niche, thrive in a single environment, more at risk of extinction
• Symbiotic relationships


  Organisms in the same ecosystem form relationships where one or both benefit
• Types of symbiotic relationships

  • Mutualism: both organisms benefit
  • Parasitism: one organism benefits, the other is harmed
  • Commensalism: one organism benefits, the other is unaffected
• Niche


  The role an organism plays in its environment, including where it lives, what it eats, its predators, and its method of reproduction
• Binomial nomenclature


  The system of naming species using a 2-part scientific name (genus + species)
• Species


  A group of organisms that can interbreed and produce fertile offspring
• Biological diversity


  The great variation of life on Earth
• Biotic factors


  Living components of an ecosystem
• Abiotic factors


  Non-living components of an ecosystem
• When a sperm and egg meet during fertilization, they form a zygote with 46 chromosomes
• Genetic engineering


  The ability to turn genes on or off, or transfer genes from one species to another to produce a desirable trait
• Mitosis


  • Cell division that produces daughter cells with the exact same DNA as the parent cell
  • Serves functions of growth, maintenance, and repair
• Meiosis


  • Cell division that produces daughter cells with half the number of chromosomes as the parent cell
  • Produces gametes (sperm and eggs)
• DNA


  The molecule passed on from parents to offspring which controls cell function, stored in chromosomes
• Heritable traits


  Traits determined solely by genetics
• Acquired traits


  Traits determined by the environment
• Mutations


  Alterations to the genetic information encoded in DNA
• Genotype


  The genetic makeup of an organism
• Phenotype


  The observable physical or biochemical characteristics of an organism
• Dominant allele


  An allele that is expressed over a recessive allele
• Recessive allele


  An allele that is only expressed when two copies are present
• Internal fertilization


  Fertilization of the egg inside the body of the organism
• Advantages and disadvantages of internal fertilization

  • Advantages: egg less likely to be fertilized or eaten by predators, greatest chance of fertilization
  • Disadvantages: mate must be found, giving birth is painful and energy-intensive
• Zygospores


  Spores produced by the fusion of two different organisms of the same species
• Bacterial conjugation


  Direct transfer of genetic material between bacterial cells, allowing for variation in inherited traits
• Gymnosperms


  Plants that produce "naked seeds" not enclosed in fruit
• Angiosperms


  Flowering plants that produce seeds enclosed in fruit
• External fertilization


  Fertilization of the egg outside the body of the organism
• Binary fission


  Asexual reproduction in single-celled organisms by duplicating DNA and splitting into two genetically identical cells
• Asexual spores


  Genetic information copied and released to spread and grow into exact copies of the parent organism
• Budding


  Asexual reproduction where a new organism grows out from the parent organism and then detaches
• Vegetative reproduction in plants

  Asexual reproduction using rapidly reproducing cells in plant roots and stems to create genetically identical copies
• Advantages and disadvantages of asexual reproduction

  • Advantages: faster, less energy-intensive, produces genetically identical offspring
  • Disadvantages: less genetic diversity, more susceptible to disease