biology

• How traits are inherited

  1. Sexual reproduction

  2. Asexual reproduction
• All organisms inherit traits through the same process
• Heredity

  Passing of traits from parents to offspring
• Genetics

  Study of how traits are passed from offspring
• Genes

  Determine everything from an organism’s shape to its life functions
• Scientists study genetics for

  • Development and disease
  • Gene controls limb development
  • Body segmentation
  • Formation of organs such as eyes and ears
  • To cure some diseases in general
• Scientists study genetics to cure some diseases in general
• Scientists study genetics for

  Common Ancestors
• Selective breeding

  Selection and breeding of organisms for desired traits
• Dominant trait

  Genetic factor that blocks another genetic factor
• Recessive trait

  Genetic factor that is blocked by the presence of a dominant factor
• Mendel’s principles of Inheritance

  • Genotype: alleles of all the genes on an organism's chromosomes
  • Phenotype: how the traits appear or are expressed
• Heterozygous

  Organism's genotype has two different alleles for a trait
• Homozygous

  Organism's genotype has two identical alleles for a trait
• Patterns of inheritance

  1. Incomplete Dominance: offspring’s phenotype is a combination of its parents' phenotype

  2. Codominance: both alleles can be independently observed in a phenotype
• Inheritance of Disease

  1. Pedigree: shows genetic traits inherited by family members

  2. Mutations: any permanent change in the sequence of DNA in a gene or a chromosome of a cell
• Genetic engineering

  The genetic material of an organism is modified by inserting DNA from another organism
• Variations

  Slight differences in inherited traits among individuals in a population
• Natural Selection

  Process by which individuals with variations that help them survive in their environment live longer, compete better, and reproduce more than those without these variations
• How natural selection occurs

  Individuals in a population have variations. They pass these variations to their offspring. When conditions change, organisms compete for resources. Individuals with certain variations are better able to survive
• Importance of natural selection to the survival of a species

  If a species were unable to adapt to a changing environment, it might become extinct
• Adaptations

  Inherited trait that increases an organism’s chance of surviving and reproducing in a particular environment. Can be structural, functional, or behavioral
• Evolution

  Change over time
• Why traits change over time

  Individuals with adaptive traits tend to produce more offspring than those without, leading to the disappearance of less useful traits over time
• Extinctions

  • Occurs when the last individual organisms of a species dies
• Causes of Extinction

  Sudden changes
• Conservation Biology

  Branch of biology that studies why many species are in trouble and what can be done to save them